brown rice research paper

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Phytochemical Profile of Brown Rice and Its Nutrigenomic Implications

Keneswary ravichanthiran.

1 Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, Kota Kinabalu 2073, Sabah, Malaysia; moc.oohay@yrawsenekr

Zheng Feei Ma

2 Department of Public Health, Xi’an Jiaotong-Liverpool University, Suzhou 215123, China; [email protected]

3 School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu 15200, Kelantan, Malaysia

Hongxia Zhang

4 Department of Food Science, University of Otago, Dunedin 9016, New Zealand; moc.liamtoh@623aixgnohgnahz

5 Department of Health Promotion, Pudong Maternal and Child Health Care Institution, Shanghai 201399, China; moc.361@gnayoacave

Chee Woon Wang

6 Department of Biochemistry, Faculty of Medicine, MAHSA University, Bandar Saujana Putra 42610, Jenjarom, Selangor, Malaysia; [email protected]

Shahzad Muhammad

7 Institute of Basic Medical Sciences, Khyber Medical University, Peshawar 25100, Pakistan; [email protected]

Elom K. Aglago

8 Joint Unit of Research in Nutrition and Food Science, Ibn Tofail University, Kenitra 14000, Morocco; moc.liamg@moleogalga

9 Division of Medicine, School of Life and Medical Sciences, University College London, London WC1E6BT, UK; [email protected]

10 Department of Clinical Nutrition, The First People’s Hospital of Wujiang District, Suzhou 215200, China; moc.621@20118891uynibnap

Whole grain foods have been promoted to be included as one of the important components of a healthy diet because of the relationship between the regular consumption of whole-grain foods and reduced risk of chronic diseases. Rice is a staple food, which has been widely consumed for centuries by many Asian countries. Studies have suggested that brown rice is associated with a wide spectrum of nutrigenomic implications such as anti-diabetic, anti-cholesterol, cardioprotective and antioxidant. This is because of the presence of various phytochemicals that are mainly located in bran layers of brown rice. Therefore, this paper is a review of publications that focuses on the bioactive compounds and nutrigenomic implications of brown rice. Although current evidence supports the fact that the consumption of brown rice is beneficial for health, these studies are heterogeneous in terms of their brown rice samples used and population groups, which cause the evaluation to be difficult. Future clinical studies should focus on the screening of individual bioactive compounds in brown rice with reference to their nutrigenomic implications.

1. Introduction

For centuries, rice ( Oryza sativa L.), one of the most well-known cereal foods, has been a primary food for many people around the world and is known to feed half of the population [ 1 ]. Therefore, the role of rice as a staple food in providing nutrition to populations has been acknowledged. In 2015, the global rice paddy production was 739.1 million tonnes, yielding 490.5 million tonnes of white rice after milling. The rice paddy production in Asia was 668.4 million tonnes, accounting for 90% of the global production, indicating that rice consumption occurs mostly in Asian countries. The environmental flexibility of culturing rice paddies at various temperatures, humidities and soil conditions allows rice to become a globally-viable crop [ 2 ]. However, the health benefits of rice were never considered because rice is considered as a staple food based on the palatability and availability. The major producers of rice are China, India and Indonesia [ 3 ].

There are more than 8000 varieties of rice, which have different types of quality and nutritional content. After the post-harvest process, all the varieties of rice can be categorised as either white or brown rice [ 4 ]. The aromatic rice varieties, known collectively as “Basmati rice”, have been sourced by people from Asian and European countries, because aroma has been considered as the highest preferred characteristic of cereal grain. Basmati rice possesses unique cereal quality features, such as long, supreme grains, characteristic aroma, swelling on cooking and tenderness of cooked rice. Basmati rice with a high amylose to amylopectin ratio and a medium glycaemic index is suitable for staple diets of diabetics [ 5 ].

Rough rice can be separated into husk and brown rice through a threshing process. The components in brown rice that was hulled from rough rice are bran layers (6–7%), an embryo (2–3%) and an endosperm (about 90%) [ 6 ]. Brown rice can be further separated into polished rice, commonly called white rice, which is obtained by removing the bran. Minor differences may exist in the degree of milling. Brown rice has a nutty flavour, chewier than white rice, but more easily goes rancid, as well [ 7 ]. The difference between brown rice and white rice can be obtained through milling [ 7 ]. White rice contains mainly the starchy endosperm. The removal of rice bran leads to a loss of nutrients. During milling, about 85% of the fat, 15% of protein, 75% of phosphorus, 90% of calcium and 70% of B vitamins (including B 1 , B 2 and B 3 ) are removed [ 7 ].

As the degree of milling increases, the loss of phytochemical compounds beneficial to health occurs, and cellular antioxidant activity decreases. Furthermore, the contents of phenolic compounds have also been shown to decrease by increasing the degree of milling. Thus, by carefully controlling the degree of milling during rice processing, both the sensory quality and nutritional composition could be optimized. Thus, brown rice with a low degree of milling (<2.7%) exhibits a more ideal balance between sensory quality and retention of beneficial phytochemicals [ 8 ]. Brown rice is a rich source of various bioactive compounds, such as γ-oryzanol, tocopherol, tocotrienol, amino acids, dietary fibres and minerals. It is less consumed than white rice because its cooking is more difficult than white rice due to its slow water absorption, and the palatability quality of brown rice is inferior to white rice [ 9 ].

There are two types of brown rice, which are germinated and non-germinated. Germinated brown rice is obtained by immersing the brown rice grain in water to initiate germination [ 10 ]. The benefits of germinated brown rice are that the nutrients found in brown rice are more easily digested and the texture of brown rice is better [ 10 ]. Germination has been employed to improve the texture of cooked brown rice. It also initiates numerous changes in the composition and chemical structure of the bioactive components. Germination could induce the formation of new bioactive compounds, such as gamma-aminobutyric acid (GABA). The consumption of germinated brown rice is increasing in many Asian countries because of its improved palatability quality and potential health-promoting functions [ 11 ].

Advances in the human genome era have shown that diet plays an important factor in the health and the causation chronic diseases such as type 2 diabetes. This is because the diet-genome interactions can result in changes especially in the proteome, transcriptome and metabolome. For example, current healthcare practitioners recommend brown rice to be consumed rather than white rice. This is due to the fact that brown rice is more nutritious. One common trait between white rice and brown rice is that they are both gluten free and contain no trans fat or cholesterol [ 7 ]. Encouraging people to eat brown rice more is a difficult challenge due to its taste, which is less likeable compared to the taste of white rice [ 7 ]. In the United States, more than 70% of rice consumed is white rice, and rice consumption has reached 9.3 kg per capita since the 1930s [ 1 ]. In addition, the consumption of brown rice is beneficial for postprandial blood glucose control because brown rice has a lower glycaemic index than white rice (55 vs. 64) [ 12 ].

Rice is the main staple food for more than half of the world’s population. The cereal was also utilised as a popular remedy since ancient times for several therapeutic purposes. Rice or rice-based products were also well documented in the traditional medicines of different Asian countries. The well-known popular uses are anti-diabetic, anti-inflammatory for the airway, ailment of gastrointestinal disorders and diarrhoea, diuretic, source of vitamins and skin preparations [ 13 , 14 ]. One of the rice varieties, red rice Rakthashali, is a staple food in India and has been described by Ayurveda practitioners as a functional food for a number of medications [ 15 ]. The medicinal rice Kullakar has high thiamine content, while the Karikalaveya variety is high in riboflavin and niacin [ 16 ].

Therefore, the aim of our work is to review the phytochemical constituents and nutrigenomic implications of brown rice in relation to animal and human studies. In addition, our work has also contributed significantly to the current understandings of brown rice with reference to the nutrigenomic implications of brown rice shown in human intervention studies. Therefore, this mini-review will provide a valuable reference resource for future studies in such areas.

Search Strategy

An electronic literature search was conducted using PubMed, Medline (OvidSP) Cochrane CENTRAL and Web of Science until December 2017. Additional articles were identified from references in the retrieved articles. Search terms included combinations of the following: rice, brown rice, phytochemicals, nutrigenomics and bioactives. The search was restricted to articles in English that addressed the phytochemical constituents and nutrigenomic implications of brown rice.

2. Phytochemical Compounds in Brown Rice

The advantages for health with the consumption of brown rice mainly come from the phytochemicals found in its bran layers [ 17 ]. Figure 1 shows the various parts of the rice grain. The phytochemical composition of brown rice cannot be dissociated from the scientific work of the Dutch Nobel prize scientist Christiaan Eijkman who initially reported the potential of brown rice and the story behind beriberi in humans in the previous centuries. Table 1 show the major phytochemical composition of brown rice. In addition to B vitamins, phytochemicals found in brown rice include dietary fibre, functional lipids, essential amino-acids, phytosterols, phenolic acids, flavonoids, anthocyanins, proanthocyanins, tocopherols, tocotrienols, minerals, gamma aminobutyric acid (GABA) and γ-oryzanol [ 11 , 17 ]. Brown rice also contains high levels of phytic acid [ 18 ].

The various parts of the rice grain.

Summary of the major phytochemical composition of brown rice.

Amongst these nutritional factors, phenolic acids are the most common substances found in brown rice [ 19 ]. Phenolics are classified under phytochemicals having one or more aromatic rings with one or more hydroxyl groups [ 20 ]. Phenolic compounds are associated with diverse human health benefits including anti-inflammatory, hypoglycaemic, anticarcinogenic, antiallergenic and antiatherosclerotic properties [ 20 ]. Examples of phenolics are phenolic acids, flavonoids, tannins, coumarins and stilbenes [ 21 ]. In rice, phenolics are found in three distinct forms, which are free, soluble-conjugated and bound forms, and the bound form is the main form among the three [ 22 ]. High levels of phenolics exist in the germ and bran layers [ 23 ]. Since brown rice does not undergo any polishing or milling, these phenolics found in the germ and bran layers are easily preserved. Free phenolics are the most readily available for absorption in the small intestine, while bound phenolics tend to be preserved throughout the intestinal tract and released in the bowel, where they interact with the microbiome to favour the Firmicutes/Bacteroidetes ratio [ 24 ]. The two main groups of phenolic acids are p-hydroxybenzoic acid and p-hydroxycinnamic acid derivatives [ 21 ]. The primary phenolic compound found in brown rice is trans -ferulic acid (range: 161.42–374.81 μg/g), a hydroxycinnamic acid that exists in the bound form [ 19 ]. The second major phenolic acid found in brown rice is trans - p -coumaric acid (range: 35.49–81.52 μg/g), which is a hydroxycinnamic acid derivative with its bound form making up about 98% [ 19 ]. Another component that is widely found is cis -ferulic acid (range: 20.76–83.02 μg/g), an isomer of trans -ferulic acid, which is found abundantly in the bound form [ 19 ].

Soluble phenolic compounds consist of free phenolic acids and hydroxycinnamate sucrose esters [ 25 ]. The main soluble phenolic compounds in brown rice are feruloylsucrose, sinapoyl sucrose and ferulic acid [ 25 ]. The components that are notable in brown rice in bound forms are 8- O -4′ diferulic acid (DFA) (range: 13.88–22.61 μg/g), 8-5′ benzofuran DFA (range: 9.28–14.79 μg/g), 5-5′ DFA (range: 7.29–13.86 μg/g) and 8-5′ DFA (range: 3.26–8.79 μg/g) [ 19 ]. The three other hydroxycinnamic acid derivatives that were found in brown rice in small amounts are caffeic acid (range: 0.00–1.44 μg/g), sinapic acid (range: 1.19–1.25 μg/g) and chlorogenic acid (0.63 μg/g) [ 19 ]. Two examples of hydroxybenzoic acid derivatives that were found are vanillic acid (range: 2.65–4.74 μg/g) and syringic acid (range: 0.47–2.52 μg/g) [ 19 ]. In brown rice, catechin (range: 4.06–8.92 μg/g), quercetin (range: 3.27–6.53 μg/g) and kaempferol (range: 1.30–3.04 μg/g) are the three main flavonoids that are usually found in the free form [ 19 ].

In contrast to white rice, brown rice is still constituted by the germ and the bran layers, which contain diverse nutritional compounds, including anti-oxidants [ 26 ]. Therefore, despite its high nutritional value, brown rice is consumed less than white rice mainly due to its appearance, longer cooking time, cost, limited availability and bioavailability and poor appreciation of its nutritional value [ 27 ]. Apart from cooking, several approaches, including germination, have been emphasized to improve the palatability and the bioavailability of the nutrients present in brown rice. Germination improves the texture and the bioavailability of the nutrients and the phytochemicals [ 25 , 28 ].

In germinated (sprouted) brown rice, about a 70% drop is found in feruloylsucrose (from 1.09–0.27 mg/100 g of flour) and sinapoyl sucrose (from 0.41–0.13 mg/100 g of flour), whereas free ferulic acid content increased (0.48 mg/100 g of flour) when compared to brown rice [ 25 ]. However, in general germinated brown rice contains less soluble phenolic compounds when compared to brown rice (1.45 vs. 2.17 mg/100 g of flour) [ 25 ]. Apart from that, the sinapinic acid level also increases ten-fold in germinated brown rice (0.21 mg/100 g of flour) compared to brown rice (0.02 mg/100 g of flour) [ 25 ]. Germination also increases the levels of the GABA in brown rice [ 28 ]. Inositol hexaphosphate is a naturally-occurring molecule found in brown rice [ 18 ]. This compound has demonstrated anti-cancer properties [ 18 ]. Selenium is a trace mineral, which is found abundantly in brown rice [ 29 ]. The function of selenium is to induce DNA repair and combine in damaged cells to promote apoptosis, which is the self-destruction of the cells in the body to remove damaged and worn out cells [ 29 ]. Selenium also functions as a cofactor of glutathione peroxidase, which is an enzyme used in the liver to detoxify many possible harmful molecules [ 29 ]. Plant lignans are one type of phytonutrient that is found widely in brown rice, which are then converted to mammalian lignan, called enterolactone [ 30 ]. Brown rice also serves as a rich source of magnesium. Magnesium plays an important role in our body, as it works as a cofactor of more than 300 enzymes [ 31 ]. About 21% of the daily value of magnesium can be obtained by consuming a cup of brown rice [ 31 ].

Brown rice contains a high amount of dietary fibre, which has been shown to protect against colorectal cancer [ 32 ] and breast cancer [ 33 ]. In an animal study, rice bran from brown rice was shown to be beneficial against the development of polyps in the bowel [ 34 ]. Due to its high content in fibre, brown rice has a lower glycaemic index, compared to white rice [ 12 ]. Consumption of brown rice compared to white rice results in improved endothelial function, without changes in HbA1c levels, possibly through reducing glucose excursions [ 35 ]. Vitamin E is also found in brown rice, mainly in two types of structure, which are tocopherols (α, β, γ and δ forms) and tocotrienols (α, β, γ and δ forms) [ 17 ]. The function of vitamin E is antioxidant activity, maintenance of membrane integrity, DNA repair, immune support and metabolic processes [ 21 ].

Regarding insoluble phenolic compounds, germinated brown rice has at least twice the total content value of insoluble phenolic compounds than brown rice [ 25 ]. Ferulic acid and p -coumaric acid are found in the highest quantity in white rice, brown rice and germinated brown rice [ 25 ]. Generally, in germinated brown rice (24.78 mg/100 g of flour), insoluble phenolic compounds are 1–2-times more when compared to brown rice (18.47 mg/100 g of flour) [ 25 ]. The high levels of phenolic compounds in germinated brown rice are due to the increase in the free forms with alkaline hydrolysis, and this is because of the dismantling of the cell wall during germination [ 25 ]. The high levels of insoluble phenolic compounds can enhance the availability of hydrolyzable insoluble phenolic compounds during the germination of brown rice [ 25 ].

Amongst other antioxidants that constitute brown rice are the flavonoids. The chemical structure of flavonoids is constituted of a 15-carbon skeleton, which itself is constituted of two aromatic rings interlinked by a heterocyclic ring. The antioxidant activity of the flavonoids stems from the phenolic hydroxyls. Flavones are the most common flavonoids found in brown rice, and tricin is the major flavonoid, accounting for more than 75% of the flavonoids in brown rice [ 36 ]. Other flavonoids such as luteolin, apigenin, quercetin, isorhamnetin, kaempferol and myricetin are at relatively low concentrations, as well as isovitexin, naringenin, hesperidin, rutin, luteolin-7- O -glucoside, apigenin-7- O -glucoside and quercetin-3- O -glucoside, amongst others that have been reported [ 36 ].

Brown rice also contains sterols present in the bran. The most common sterol is γ-oryzanol, a ferulic acid ester of major phytosterols: campesterol, stigmasterol and β-sitosterol or triterpene alcohols [ 36 ]. The γ-oryzanol exhibits several physiological properties including effects on the anthropometry and muscles, cholesterol levels and potential anti-cancer properties [ 37 ]. Several analytical methods have been used for the determination of the phytochemical compounds in rice [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ] ( Table 2 ).

Summary of analytical methods used to identify the phytochemical compounds in rice.

Microbial Profiling in Brown Rice

Since the bran and embryo of brown rice are rich in vitamins and fibre, brown rice has the capacity to harbour more microbial association than white rice [ 48 ]. During germination, the quality of rice will be improved because the high molecular weight polymers undergo hydrolysis to produce GABA, amino acids, fibres and other bioactive compounds [ 9 ]. The germination usually takes place in a warm and humid condition, which favours the growth of microorganisms [ 49 ]. The germination of brown rice is initiated when soaking of brown rice occurs. This process involves fermentation because the microbial flora of the environment act upon it after the brown rice is soaked in the water for a certain period of time [ 50 ]. Some of these microorganisms can be either harmful or beneficial for consumers [ 51 , 52 , 53 , 54 , 55 ]. For example, some lactic acid bacteria including Lactobacillus fermentum, Pediococcus pentosaceus and Weissella confuse are detected in germinated brown rice [ 56 ]. Table 3 shows the types of microbial association in rice.

Summary of major microbial association in rice.

3. Nutrigenomic Implications of Brown Rice

Similar to other plants [ 57 , 58 , 59 , 60 ], although the review of the literature has reported on the health benefits of brown rice, these studies often cannot provide the direct causal relationship between a bioactive compound of brown rice and the observed health benefits. Therefore, it is important to note that these studies should not be over-interpreted because this might be the simplification of the complicated mechanisms in the body that lead to such observed health benefits related to the consumption of brown rice. For example, the review of the literature has shown that brown rice is associated with a wide range of pharmacological properties such as anti-diabetic, anti-cholesterol, anti-hyperlipidemic, cardioprotective and antioxidant [ 61 , 62 , 63 , 64 , 65 , 66 , 67 ]. Table 4 shows the summary of some important nutrigenomic mechanisms involved in brown rice

Summary of some important nutrigenomic mechanisms involved in brown rice.

3.1. Anti-Diabetic Effect

Type 2 diabetes is a worldwide epidemic affecting millions of people across the world and associated with significant morbidity and mortality. Diet and life style factors play an important role in the pathogenicity of type 2 diabetes. Therapeutic management of the disease is only partially effective, costly and associated with adverse side effects. Therefore, scientists and healthcare professionals are looking for alternative management approaches that are safe, affordable and easily accessible to people, especially those residing in the low and middle income countries. In recent years, a considerable increase in scientific research has been observed regarding the use of brown rice for effective management of diabetes mellitus since it is the main staple food in many parts of the world, especially developing countries of Asia and Africa.

Several population-based studies have shown increased risk of type 2 diabetes associated with the intake of white rice, while higher dietary intake or substitution of white rice with brown rice in the diet may decrease the risk [ 1 , 27 ]. In the same context, results of clinical studies are also encouraging. Recently, a research group in Japan has reported a significant decrease in postprandial glucose level in diabetic patients following consumption of glutinous brown rice for one day [ 68 ]. The same group has also reported improved glycaemic control in diabetic patients even after eight weeks of ingestion of glutinous brown rice [ 69 ]. Using an open-labelled, randomized cross-over study design, they observed a significant decrease in postprandial plasma glucose, haemoglobin A1c (HbA1c) and glycoalbumin levels in patients who ate glutinous brown rice twice a day compared to those on white rice. Another study of similar duration and dietary intervention on Japanese diabetic patients has also reported decreased levels of postprandial plasma glucose levels and improved endothelial function. However, no significant changes were observed in the HbA1c level [ 35 ]. Similarly, a randomized controlled trial on Korean type 2 diabetic patients who followed a brown rice-based vegan diet for 12 weeks have also shown improved glycaemic control (larger reductions in HbA1c level) compared to those who followed the conventional diabetic diet [ 70 ].

Several other clinical studies have also reported a decreased glycaemic index and better glycaemic and insulin responses in healthy, diabetic and overweight subjects following consumption of brown rice [ 71 , 72 , 73 , 74 ]. All these beneficial effects are mainly attributed to several bioactive compounds present in brown rice. Brown rice has been shown to prevent type 2 diabetes in several studies [ 68 , 69 , 75 ]. Brown rice has a crucial role in lowering postprandial blood glucose levels in humans [ 75 ]. Apart from that, it also helped in weight management and ameliorated glucose and lipid dysmetabolism in individuals with metabolic syndrome. Brown rice contains high amounts of dietary fibre and other polysaccharides such as arabinoxylan and β-glucan. These fibres and polysaccharides help in regulating glucose absorption in the intestine, thus lowering the glycaemic index [ 76 , 77 ]. It also acts as growth substrates for these components to help in the growth of beneficial bacteria in the gut such as Lactobacillus and Bifidobacterium [ 78 ], thus modulating the gut microbial composition and helping in the prevention of diabetes and obesity [ 75 , 79 ]. It is found that in a recent study, there was a significant relationship between the composition of the intestinal microbiota, obesity and type 2 diabetes [ 75 ]. Brown rice is proven to have an important effect on the gut microbial composition in humans. This further supports that there is a relationship between the profile and activity of the intestinal microbiota with the anti-obesity and anti-diabetic effects of brown rice [ 75 ].

The rice bran in brown rice is rich in γ-oryzanol, which is responsible for many pharmacological properties, such as cholesterol lowering, anti-inflammatory, anti-cancer, anti-diabetic and antioxidant activities. Brown rice ameliorated glucose tolerance and insulin resistance. A lower glycaemic index was observed in healthy (12.1% lower) and diabetic subjects (35.6% lower) due to consumption of brown rice, and this could help to avoid type 2 diabetes and control glycemia, respectively [ 74 ]. These effects are due to the rich bioactive content found in brown rice [ 63 ]. A study by Sun et al. [ 1 ] has proven that consumption of white rice increased the chances of type 2 diabetes, while substituting one third of the daily serving with brown rice lowered the risk of type 2 diabetes in 200,000 subjects. Brown rice that undergoes germination also has differences in its properties, whereby it is less chewy and richer in bioactive compounds [ 63 ]. In germinated brown rice, the high content of dietary fibre helps to decrease the glycaemic index by regulating the absorption of glucose in the intestines [ 76 ]. Hypoadiponectinemia, which is implicated in reduced insulin sensitivity in diabetes, can be stopped by γ-oryzanol that is found in brown rice [ 80 ]. It also acts on pancreatic islets and increases glucose-stimulated insulin secretion [ 75 ]. In addition, GABA, another important bioactive present in brown rice, also has shown a similar effect against hypoadiponectinemia [ 81 ].

Similarly, acylated steryl glycoside (ASG), a component found in brown rice, regenerates sodium potassium adenosine triphosphatase and homocysteine thiolactonase enzymes with potential to reverse diabetic neuropathy and oxidative changes on biomolecules [ 82 ]. It also enhanced the overall metabolic condition in diabetes as a result of the induction of insulin-like growth factor-1 and reduced oxidative stress, which is a problem in type 2 diabetes [ 83 ]. The molecular targets of all these bioactive compounds discussed above are not known. However, it is believed that dysregulation of peroxisome proliferator-activated receptors gamma (PPARγ) is linked to the development of metabolic conditions including type 2 diabetes. Thus, PPARs can be a potential target for bioactive compounds, including those present in germinated brown rice. Indeed, a study by Imam et al. has already reported upregulation of PPARγ following treatment of HEP-G2 cells with germinated brown rice bioactive compounds. Upregulation of PPARγ has therapeutic potential in the management of diabetes.

3.2. Anti-Dyslipoproteinemia

Dyslipoproteinemia is a group of heterogeneous disorders characterized by elevated plasma cholesterol, triglycerides and lipoproteins level. Dyslipoproteinemia is an important risk factor for an array of clinical conditions including atherosclerosis, cardiovascular diseases and acute pancreatitis [ 84 ]. Diet plays an important role in inducing dyslipoproteinemia as evident by the rise in the incidence of the disease due to the intake of modern diets high in fats, sugars and refined grain products. Many studies have demonstrated that brown rice also has anti-dyslipoproteinemia and cholesterol lowering effects in animal models. A study by Shen et al. [ 85 ] reported an improved lipid profile (significantly decreased level of triglycerides, total cholesterol, high density lipoprotein and non-high density lipoprotein) in mice fed with pre-germinated brown rice-containing high fat diet for 16 weeks. The authors reported that feeding mice with a high fat diet induced dyslipidemia, which can be successfully averted when the mice were fed a high fat diet supplemented with pre-germinated brown rice [ 85 ]. The exact mechanisms are not known; however, this might be achieved by decreasing lipid absorption and synthesis and increasing lipid metabolism. The germinated brown rice extract administration in high fat diet-induced obese mice resulted in a significant reduction in serum triglycerides and total cholesterol levels by suppressing lipogenesis via downregulation of genes involved in lipid synthesis [ 86 ].

Another pre-clinical study by Miura et al. [ 87 ] reported that feeding hepatoma-bearing rats with white rice resulted in hypercholesteremia, which could be successfully suppressed when the rats were fed with a diet containing germinated brown rice. They probably do so by upregulating cholesterol catabolism. Other studies have also reported anti-dyslipoproteinemia and cholesterol lowering effects of germinated brown rice [ 88 , 89 ]. Human clinical studies evaluating the effects of germinated brown rice on dyslipoproteinemia are limited. In a clinical study involving sixty Vietnamese women (aged 45–65 years) with impaired glucose tolerance, the impact of germinated brown rice and white rice intake on blood glucose and lipid profile was evaluated. Following four months of intervention, Bui et al. [ 90 ] observed an improvement in blood glucose and lipid level in the pre-germinated brown rice diet group compared to the white rice group.

Similarly, a randomized control trial on 11 diabetic patients also reported a significant reduction in serum total cholesterol and triglyceride level following consumption of pre-germinated brown rice for 14 weeks compared to white rice group [ 91 ]. However, no such improvement in serum lipid profile and other metabolic parameters was observed in healthy volunteers who followed either a white rice diet or a white rice plus germinated brown rice diet (1:1, w / w ) for 11–13 months [ 92 ]. However, this may be due to the presence of white rice in the diet, which diminishes the beneficial effects of germinated brown rice [ 72 ]. Hypercholesterolemia induced by hepatoma growth can be suppressed by means of upregulating cholesterol metabolism. Germinated brown rice also has a greater effect on the restorative effects on cholesterol levels compared to brown rice. This proves that germinated brown rice has a greater impact on high blood cholesterol [ 88 ]. All these beneficial activities of brown rice are mainly attributed to the presence of the high concentration of various biologically-active components such as GABA, dietary fibre, γ-oryzanol and other antioxidants in brown rice that help in preventing hyperlipidaemia. The risk of atherogenesis and coronary artery disease through its protection against LDL oxidation can be reduced by the antioxidant contents in brown rice and germinated brown rice [ 10 , 93 ].

3.3. Anti-Cancer Effect

Recent studies have reported the chemo-preventive and anticancer potential of some biologically-active molecules present in germinated brown rice. These molecules can prevent or suppress cancer development. Chemopreventive activities of germinated rough rice have been demonstrated in a recent study [ 94 ]. Using azoxymethane, colon cancer was induced in six-week-old male Sprague-Dawley rats followed by oral administration of either control diet or different doses of germinated rough rice crude extract (2000, 1000 and 5000 mg/kg body weight) once daily for eight weeks. The study showed a dose-dependent reduction in the size and number of aberrant crypt foci formation and β-catenin expression in rats fed with germinated rough rice crude extract.

Similarly, a study by Latifah et al. [ 95 ] also showed a significant decrease in aberrant crypt foci formation and β-catenin and cox-2 expression when azoxymethane-induced colon cancer rats were fed with different doses of germinated brown rice (2.5, 5 and 10 g/kg body weight). From germinated brown rice, GABA-enhanced parts were extracted, and they portrayed inhibitory action on the reproduction of some cancer cells and a stimulatory action on immune responses. GABA-enriched extracts from germinated brown rice had also been shown to inhibit effects on leukemic cells’ proliferation and to stimulate cancer cells in terms of apoptosis [ 96 ]. GABA may also play a role in protecting smokers from pulmonary adenocarcinoma due to the reported tumour suppression activity in small airway epithelia [ 97 ]. Besides GABA, other bioactive compounds such as tocopherols and tocotrienols present in brown rice may also exhibit anticancer potential [ 98 ]. All these studies suggest the potential role of germinated brown rice in cancer prevention. However, further epidemiological and clinical studies are required in order to utilize germinated brown rice as a staple food in cancer prevention activity and for its inhibitory effect. The leukaemia cells that were treated with germinated brown rice extract showed greater DNA fragmentation compared to leukaemia cells treated with brown rice [ 11 ]. Apart from that, immunoregulatory activities found in germinated brown rice enhance the cell proliferation of mesenteric lymph node cells in vitro and also increase murine splenic B, T-helper cell subpopulations and nitric oxide c- interferon production [ 96 ].

3.4. Lowering Cholesterol

GABA found in brown rice also helps to nourish blood vessels, regulate insulin secretion, avoid increasing blood cholesterol, reduce emotional unrest, improvement from stroke, better the kidney and liver function and prevent chronic alcohol disease [ 11 ]. The rice bran oil (RBO) found in brown rice can help to reduce the atherogenic level and increase HDL cholesterol. The cholesterol-reducing activity induced by RBO was due to the decreased absorption-reabsorption of cholesterol and the interference of the plant sterols in cholesterol metabolism. When the unsaponifiable matters of rice bran were fed to hamsters in a study, the faecal fat and neutral sterol excretion was greater. This shows that there is a decrease in fat digestibility [ 11 ].

3.5. Cardio-Protective Effect

Cardiovascular disease (CVD) includes diseases of the heart and circulatory system including angina, hypertension, heart attack, congenital heart disease and stroke. On a global scale, CVD is the most common cause of death with an estimated 17.7 million people dying because of CVD in 2015 [ 99 ]. To reduce the risk and increase protection against CVD, effective nutritional intervention has always been a focus of public health strategies. In this regard, brown rice and its bioactive compounds have been reported to possess anti-hyperlipidemic, anti-hypercholesteraemic and antihypertensive potential and thus have a role in preventing CVD.

Recently, a randomized cross-over clinical trial was conducted to evaluate the effect of brown rice consumption on inflammatory markers and cardiovascular risk factors [ 100 ]. Forty non-menopausal overweight or obese women (BMI > 25) were recruited and divided into two groups. Participants in both groups were asked to consume 150 g cooked brown rice or white rice for six weeks, followed by a two-week wash out period and switching over to an alternate diet for six weeks. Results of the study revealed that consumption of brown rice can significantly reduce inflammatory markers (CRP) and other risk factors (weight, BMI, waist, diastolic blood pressure) associated with CVD.

Another clinical study on healthy female university students revealed that ingestion of brown rice as a staple food for 10 weeks improved general health and prevented hyperlipidaemia, thus protecting against CVD [ 101 ]. Several pre-clinical studies have also reported anti-hypertensive effects of germinated brown rice in spontaneously hypertensive rats [ 102 , 103 ]. Mechanistic studies revealed that the antihypertensive effects may be due to the presence of several bioactive compounds in brown rice such as GABA, dietary fibres and ferulic acids [ 104 , 105 ]. On this basis, germinated brown rice can be a good choice as a staple diet or functional food to prevent CVD.

3.6. Antioxidant Effect

Brown rice contains many types of phenolic acids, which are well known for their antioxidant activities and one of the most common antioxidants in our diet. They can protect cells against oxidative damage, thereby reducing the risk of diseases associated with oxidative damage. Prevention of diseases such as cardiovascular disease, type 2 diabetes, obesity and cancer is possible due to the high antioxidant levels found in brown rice. The phenolic acids from brown rice also are assumed to contain chemopreventive properties for breast and colon cancer [ 106 ]. Based on the sensory attributes, the whole rice grain is harder to chew and has less taste qualities. Thus, pre-germinated rice is favoured. Brown rice is first soaked in water to initiate germination and contains a higher nutritional value. It is also shown that pre-germinated brown rice increases mental health and immunity. It also helps to prevent diabetic decline [ 107 ]. Hepatic fibrosis is one of the most prevalent health problems, and it can be prevented by consuming brown rice. Ferulic acid, p -coumaric acid, γ-oryzanol, γ-tocotrienol, GABA and other components in pre-germinated brown rice can decrease liver inflammation and fibrosis and hence reduce the risk of liver cirrhosis and cancer [ 108 ].

4. Conclusions and Future Research

Our review has highlighted that brown rice contains certain bioactive phytochemical compounds that might be associated with some important nutrigenomic implications. Therefore, brown rice has received increasing attention from consumers who are health-conscious. In addition, our review also suggests that there are several opportunities for the food industry to develop a wide range of food products using brown rice as the main ingredient. Similar to other plants [ 59 , 60 , 109 ], future research should be designed to screen for the individual bioactive components that might be associated with the nutrigenomic implications of brown rice.

Acknowledgments

Zheng Feei Ma would like to thank Siew Poh Tan, Peng Keong Ma and Zheng Xiong Ma for their active encouragement and support of this work. The authors received no specific funding for this work.

Author Contributions

The project idea was developed by Z.F.M., K.R. and Z.F.M. wrote the first draft of the manuscript. K.R., Z.F.M., H.Z., Y.C., C.W.W., S.M., E.K.A., Y.Z., Y.J. and B.P. conducted the literature review and revised the manuscript.

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

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Brown Rice Versus White Rice: Nutritional Quality, Potential Health Benefits, Development of Food Products, and Preservation Technologies

Affiliations.

• 1 College of Grain Science and Technology, Shenyang Normal Univ., Shenyang, 110034, Liaoning, China.
• 2 Dept. of Food Science and Technology, Faculty of Agriculture, Assiut Univ., Assiut, 71526, Egypt.
• PMID: 33336992
• DOI: 10.1111/1541-4337.12449

Obesity and chronic diet-related diseases such as type 2 diabetes, hypertension, cardiovascular disease, cancers, and celiac are increasing worldwide. The increasing prevalence of these diseases has led nutritionists and food scientists to pay more attention to the relationship between diet and different disease risks. Among different foods, rice has received increasing attention because it is a major component of billions of peoples' diets throughout the world. Rice is commonly consumed after polishing or whitening and the polished grain is known a high glycemic food because of its high starch content. In addition, the removal of the outer bran layer during rice milling results in a loss of nutrients, dietary fiber, and bioactive components. Therefore, many studies were performed to investigate the potential health benefits for the consumption of whole brown rice (BR) grain in comparison to the milled or white rice (WR). The objective of this work was to review the recent advances in research performed for purposes of evaluation of nutritional value and potential health benefits of the whole BR grain. Studies carried out for purposes of developing BR-based food products are reviewed. BR safety and preservation treatments are also explored. In addition, economic and environmental benefits for the consumption of whole BR instead of the polished or WR are presented. Furthermore, challenges facing the commercialization of BR and future perspectives to promote its utilization as food are discussed.

Keywords: brown rice; chronic diseases; dietary fiber; health benefits; nutritional quality; white rice.

© 2019 Institute of Food Technologists®.

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Brown Rice: Nutritional composition and Health Benefits

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• Published: 30 March 2024

Untargeted metabolomics-based network pharmacology reveals fermented brown rice towards anti-obesity efficacy

• Kaliyan Barathikannan   ORCID: orcid.org/0000-0003-2316-5249 1 , 2 ,
• Ramachandran Chelliah 3 , 4 ,
• Annadurai Vinothkanna 5 , 6 ,
• Ragothaman Prathiviraj 7 ,
• Akanksha Tyagi 3 ,
• Selvakumar Vijayalakshmi 3 ,
• Min-Jin Lim 3 ,
• Ai-Qun Jia   ORCID: orcid.org/0000-0002-8089-6200 6 &
• Deog- Hwan Oh   ORCID: orcid.org/0000-0002-7472-0436 3  

npj Science of Food volume  8 , Article number:  20 ( 2024 ) Cite this article

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There is a substantial rise in the global incidence of obesity. Brown rice contains metabolic substances that can help minimize the prevalence of obesity. This study evaluated nine brown rice varieties using probiotic fermentation using Pediococcus acidilacti MNL5 to enhance bioactive metabolites and their efficacy. Among the nine varieties, FBR-1741 had the highest pancreatic lipase inhibitory efficacy (87.6 ± 1.51%), DPPH assay (358.5 ± 2.80 mg Trolox equiv./100 g, DW), and ABTS assay (362.5 ± 2.32 mg Trolox equiv./100 g, DW). Compared to other fermented brown rice and FBR-1741 varieties, UHPLC-Q-TOF-MS/MS demonstrated significant untargeted metabolite alterations. The 17 most abundant polyphenolic metabolites in the FBR-1741 variety and 132 putative targets were assessed for obesity-related target proteins, and protein interaction networks were constructed using the Cystoscope software. Network pharmacology analysis validated FBR-1741 with active metabolites in the C. elegans obesity-induced model. Administration of FBR-1741 with ferulic acid improved lifespan decreased triglycerides, and suppressed the expression of fat-related genes. The enhanced anti-obesity properties of FBR-1741 suggest its implementation in obesity-functional food.

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Introduction.

Obesity is a chronic disease due to significant fat accumulation in the body. By 2025, 167 million people and children will be unhealthy due to obesity, according to the World Health Organization (WHO) 1 . International dietary guidelines encourage the consumption of whole grains, especially brown rice, to minimize the risk of obesity, cardiovascular diseases, and type 2 diabetes 2 . The development of bio-functional materials increases the concentrations of the following substances: bioactive substances, γ-aminobutyric acid (GABA) 3 , ferulic acid, tocotrienols, potassium, zinc, and amino acids. Brown rice (BR) is a nutrient-dense food abundant in antioxidants, minerals, and other beneficial compounds. Brown rice’s low glycemic index could be beneficial to overweight people. Brown rice decreases the risk of obesity, while eating the same white rice elevates blood sugar levels after meals.

Grains provide a good alternative to dairy because, in addition to other nutritional advantages, they benefit from probiotic organisms that survive and are impervious to bile. Numerous cutting-edge technologies, such as bioconversion via fermentation, have been implemented to enhance the qualities of BR. Probiotic fermentation is recognized for improving animal and plant products’ dietary, sensory, and functional qualities. Fermentation is the most common and cost-effective means of enhancing food bioactive compounds. Fermented rice products prevent harmful bacteria and enhance flavor, texture, and consistency. Bioconversion/biotransformation utilizing catalysts and whole microbial organisms have produced alcoholic beverages and food from earlier civilizations 4 . Cereal-based fermented foods are healthy because they include beneficial bacteria and vitamins. The fermented cereals make organic acids, bacteriocins, and volatile substances essential for food safety, shelf life, and flavor. This group of bacteria includes Streptococcus and Corynebacterium species, as well as Limosilactobacillus fermentum , Lactiplantibacillus plantarum , Lactococcus lactis , Levilactobacillus brevis , Pediococcus species, and Leuconostoc species 5 . Liquid fermentation accelerates the production of metabolites, which depend on microbe proliferation 6 . Compared to the enzymatic process, microbial fermentation is the preferred commercial methodology for synthesizing active molecules due to its low cost and minimal environmental impact 7 . Polyphenolic compounds found in fermented brown rice have several physiological effects, such as significantly reducing blood cholesterol levels 8 .

Metabolomics is an approach for analyzing and effectively detecting molecules in sophisticated biological or fermentation systems. In fermentation, secondary metabolites may alter bacterial growth and metabolism. The alterations in metabolites can be used to infer the function of metabolic networks. Recent research has used NMR and UHPLC-Triple-TOF-MS/MS to identify the metabolic profile and delve into the highly overlapped metabolites 9 . High-throughput metabolomics is a developing field of research that analyzes the spectrum of metabolites found in biological samples. The primary objective of the multiomics approach is to find biomarkers of disease and promising biological targets for highly efficient drug screenings. Multiomics analyses investigate the molecular linkages to disease using environmental factors like diets. Omics’ investigations in humans and animals provide information on multiple diseases. In recent research on metabolic disease, omics’ findings from human and animal models were compared to confirm their clinical significance 10 . Bioinformatics analysis has helped find genomic biomarkers accurately from a large number of candidates at a lower cost and in less time compared to wet-lab-based experimental approaches for disease evaluation, prediction, and interventions 11 . Network pharmacology is a novel and effective approach for investigating the pharmacological process and revealing the functions and behaviors of sophisticated biological systems. Differentially expressed genes (DEGs) and hub genes can be used to study disease-related signaling networks and processes to predict targeted drugs 12 . For almost three decades, molecular docking has been a significant method for drug discovery, leading to the identification and development of many new drugs. Docking studies investigating the atomic-level interactions between a small metabolite and a protein, characterize molecules at target protein-binding sites and support the understanding of human diseases at the cellular level 13 , 14 .

In biomedical and nutritional research, Caenorhabditis elegans is a very useful model organism because it has a short life cycle, a unique way of absorbing fatty acids, simple genetics that is similar to humans, and it is easy to make mutants with targeted deletions of long-chain fatty acid metabolizing genes. In clinical research, these are generally prohibited due to ethical considerations and are expensive and time-consuming 15 . The C. elegans , a multicellular model organism, is small, inexpensive, easy to cultivate, has short generation cycles, and is genetically customizable. In C. elegans , triggering 112 genes raises fat stores, while suppressing 305 genes diminishes fat 16 . The hypodermic and intestinal cells of C. elegans contain lipids, which are simple to stain. Lipid affinity dyes allow for the visualization of fat accumulation and the convenient identification of lipid droplets in C. elegans . Decreased fat levels are linked to silencing the genes sbp-1 , hosl-1 , fat-4 , fat-5 , fat-6 , and fat-7 , which code for delta-9 fatty acid desaturation enzymes 17 . Dietary restriction (DR) extends the lifespan of several animals. DAF-16 modulates the insulin/IGF-1 signaling pathway in C. elegans , promoting lifespan 18 . In C. elegans , several SFAs, MUFAs, and PUFAs, including ω-6 AA (20:4ω-6), ω-3 EPA (20:5ω-3), and monomethyl branched-chain fatty acids, are present, as in humans 19 .

In this work, we explore the possibility of using fermentation methods to enhance the bioactive components and antioxidants in brown rice in order to develop functional foods that prevent obesity. We investigated the in vitro lipase inhibition assay and antioxidant properties of FBR. In addition, a network pharmacology method was applied to the identification of obesity-related metabolites using the UHPLC Q-TOF MS/MS technique, which was used to discover FBR metabolites. Furthermore, a C. elegans obesity model could be employed to validate the effect of the metabolites and FBR-1741 components by observing changes in lipid metabolism and reducing an accumulation of fat.

Results and discussion

Effect of brown rice fermentation.

The nine brown rice varieties were evaluated for P. acetolactic MNL5. FBR-1741 exhibited the highest pancreatic lipase inhibitory activity among the nine brown rice varieties at the 48 h optimized incubation time. Furthermore, the strongest TPC, TFC, and antioxidant activities were also observed. In earlier investigations, fermenting diverse substrates increased the bioactive chemicals and anti-obesity potential in the MNL5 strain. Fermentation stimulates the biochemical processes of bacteria, which break down the cell wall structurally, producing various bioactive metabolites 16 .

Impact of FBR on lipase inhibition

The inhibitory activity of the pancreatic lipase enzyme and the associated compounds is shown in Fig. 1a , the fermentation process enhanced the lipase activity of brown rice compared to that of other rice varieties. Lipase inhibitory activity was highest in 1741 (87.6 ± 2.1%) > 1708 (79.2 ± 1.6%)>, while DM25 (62.5 ± 1.9%) and DM29 (59.5 ± 2.1%) showed enhancement. Lipase inhibition is an efficient technique for preventing the absorption of triacyl glycerides in people who suffer from hypercholesterolemia. Fermented materials suppress pancreatic lipase, although few reports have been published. Moreno et al. 20 observed 80% lipase inhibition with 1 mg/mL grape seed extract. In addition, Wang et al. 21 revealed that NTU 101-fermented green tea promotes lipase activity in adipocytes to limit lipid droplet formation and increase lipolysis.

a Anti-obesity in vitro pancreatic lipase inhibitory activity of fermented Brown rice extracts. b Total phenolic content (TPC). c Total flavonoid content (TFC). d Antioxidant activity. Each bar represents the mean ± SD of triplicate values. https://doi.org/10.6084/m9.Figureshare.24781476 .

Total phenolic and flavonoid content of FBR

Figure 1b, c shows the TPC and TFC of nine varieties of fermented brown rice. TPC and TFC increased in FBR-1741 compared to the other FBR varieties. After comparison, FBR-1741 had the highest total phenolic and flavonoid content (TPC-343.5 ± 3.89 mg GAE equiv./100 g, DW; TFC-220.5 ± 3.81 mg GAE equiv./100 g). The second improved TPC and TFC content was FBR 1708 (Fig. 1b, c ). The overall phenolic and flavonoid content is anticipated to benefit the antioxidant activity. Our findings suggest that more work is needed to boost the bioactivity of polyphenolics in FBRs and achieve antioxidant efficiency. Most cereals contain esterified connections to the matrix of the grain wall due to a lack of phenolic compounds 21 . Fermentation is a possible method for increasing the bioavailability of grain phenolics 22 . The above method may release insoluble or bonded phenolic substances. The current study compared nine varieties with fermentation using MNL5 and found that FBR-1741 enhanced polyphenols compared to other brown rice varieties from Korean resources.

The effect of DPPH, ABTS, and FRAP scavenging activity

The enhanced antioxidant properties of brown rice extracts have been attributed to reducing capacity, metal ion chelation, and radical scavenging, among other mechanisms 23 . Absorption spectroscopy is a popular method for measuring the antioxidant activity of natural materials. FBR-1741 (358.5 ± 2.8 mg Trolox equiv./100 g, DW) and FBR-1708 (338.5 ± 3.1 mg Trolox equiv./100 g, DW) had the highest DPPH values. With the lowest results (156.5 ± 2.5 mg Trolox equiv./100 g, DW), FBR-DM21 was tested. Therefore, ABTS is necessary to assess the radical scavenging ability of grain. While the FRAP test was primarily designed to measure antioxidant capacity in plasma, it is now routinely used to analyze antioxidant capacity in isolated chemicals and biological materials 24 . It recognizes changes in absorbance brought on by blue iron (II) derived from iron oxide (III). The highest ABTS activity was observed in FBR-1741 (362.5 ± 3.3 mg Trolox equiv./100 g, DW). In addition, FBR-DM21 has the lowest ABTS activity. Similar results with DPPH were obtained in this study’s ABTS and FRAP tests. MNL5 FBR-1741 contained the maximum levels of FRAP (295.53.3 mg Trolox equiv./100 g, DW), followed by 1708 and DM21 (Fig. 1d ). MNL5 FBR-1741 had the highest activity level out of the nine samples, according to the findings of the antioxidant assays. These results were greater than those reported previously by IIowefah et al. 25 for fermented brown rice flour. The bioavailability of phenolics and flavonoids, as well as antioxidant activity, can be measured using this method, revealing variations in the extracts’ antioxidant activity. In addition, their chemical composition strongly influences the quenching power of the phenolic compounds. Antioxidants help prevent aging, obesity, and diabetes, which have been shown to be associated with the action of free radicals, as well as the degradation of essential fatty acids 26 . In recent years, fermentation has been regarded as an efficient method for enhancing the antioxidant activity of grains. Landete et al. 27 reported the glycosidase activity of L. plantarum in relation to enhancing the bioaccessibility and bioavailability of dietary phenolic compounds and resulting in greater antioxidant activity. Our results show that FBR-1741, which was evaluated by DPPH, ABTS, and FRAP methods, has the strongest antioxidant activity.

UHPLC-Q-TOF-MS/MS to identify the polyphenols in fermented brown rice

Our study used METLIN and the Metabolomics Workbench to assist us in determining the classification of polyphenolics. Table 1 shows that 17 phenolic substances were found in the ethanolic extracts of FBR-1741. This study obtained high amounts of phenolic substances formed in optimized conditions within 48 h. In addition, after 48 h of fermentation, ferulic acid, cinnamic acid, p -coumaric acid, protocatechuic acid, ethyl 4-hydroxybenzoate, caffeic acid, homovanillic acid, butylparaben, gallic acid, quercetin, isorhamnetin, sophoricoside, phenprobamate, daphnetin, cantharidin, genipin, and irisflorentin were identified. UHPLC-Q-TOF-MS/MS analysis identified 17 components in FBR, including 11 phonic compounds, four flavonoids, and two organic acids (Supplementary Fig. 1a–d ). All of the top 17 active metabolites, especially ferulic acid, quercetin, isorhamnetin, irisflorentin, and protocatechuic acid, have a role in maintaining lipid metabolic stability. However, the FBR-1741 type exhibited the greatest level of phenolic compounds found. Based on our study, UHPLC-Q-TOF-MS/MS reveals the enhanced polyphenolic metabolites for FBR-1741 for anti-obesity functionality. In addition, 1708 shows 14 phenolic substances were found in the ethanolic extracts (Supplementary Table 1 ). Kuppusamy et al. 28 observed that FA was imperative for antiadipogenic and lipogenic effects by regulating key adipocyte factors and enzymes and accelerating lipolysis via the HSL/perilipin mechanism. In addition, another investigation showed that ferulic acid reduced the risk of NAFLD and was developed as a functional food or beneficial substance 28 . In our prior study, fermented onion lowered cholesterol and enhanced quercetin to improve pancreatic lipase activity for synergistic anti-obesity benefits 16 . Isorhamnetin suppressed body fat and enhanced fat oxidation in the NHR-49-dependent pathway by lowering fat accumulation in a C. elegans study 29 . Jung et al. 30 found that caffeic acid may reduce hyperglycemia by stimulating insulin secretion and reducing insulin resistance in db/db mice. Quercetin also improved the insulin resistance index, antioxidant enzyme activity, and insulin signaling in high-fat-diet-fed animals, showing its free-radical scavenging properties 31 .

Network pharmacology relations for FBR-1741 metabolites

In the present study, 132 common target genes for obesity were acquired from available databases such as TCMSP, DisGeNET, and GeneCards (Supplementary Fig. 1a ). The obesity-associated target genes interaction with 17 active metabolites chosen from FBR is provided in Supplementary Table 2 . Drug screening criteria parameters, including OB, DL, and BBB, were selected for these 17 active compounds. The obesity-related target gene (132) interaction network was constructed using the STRING database with a high confidence score (0.700) (Supplementary Fig. 1b ). The major hub proteins are vital in controlling and expressing all interacting sub-proteins to carry out their biological and molecular functions at any time. Five top-ranked hub proteins (VEGFA, AKT1, JUN, IL-6, and MMP9) were associated with the target disease–gene interaction network (Supplementary Fig. 1c ). These selected hub proteins may be controlled/regulated by the biological and molecular functions of the remaining disease-associated target genes. According to the DisGeNET and GeneCards database analyses, five compounds showed the best drug-likeness networking properties against the five hub proteins. The bioactive FBR compounds (17) interacted with five hub proteins and the remaining disease-associated target genes. Among the 17 FBR compounds, ferulic acid, quercetin, isorhamnetin, protocatechuic acid, and irisflorentin had significant interactions with the top five hub proteins (Fig. 2 ). These results indicated that these FBR compounds might regulate or influence the genes related to obesity. Authenticating the hypothesis that VEGF-A concentration in serum is strongly associated with body mass index, elevated levels of VEGF-A were detected in humans as well as animal models that have become overweight or obese 32 . Adipose-VEGF stimulation reverses a cascade of events—adipocyte death, hypoxia, inflammatory processes, abnormal fat accumulation, and lipotoxicity—in chronically confronted animals and maintains glucose balance. According to Robciuc et al. 33 , inhibiting VEGFR-2 (KDR gene-encoded protein) activation might lower obesity by inhibiting angiogenesis and reducing fat mass. Shearin et al. 34 showed that AKT1 signaling downstream of insulin and IGF-1 receptors regulates fat formation and regulation. IL-6 is an inflammatory factor that may predict insulin resistance and cardiovascular disease and contribute to their development. It is connected to abdominal adipose tissue and may influence TNF-α and other inflammatory factors. IL-6 and TNF-α are known to be produced by adipose tissue and may contribute to body mass augmentation 35 . According to Wang et al. 36 , network pharmacology-guided baicalin may reduce obesity by upregulating SLC2A1 and downregulating TNF, NFKB1, SREBF1, PPRGA, and CASP3. The current work focuses on the strong connections that VEGFA, AKT1, JUN, IL-6, and MMP9 hub genes for obesity-related functions have with the FBR-1741 metabolites.

The blue table nodes represent the 17 components, the red diamond represents the hub-gene, and the green circle nodes represent the corresponding 132 target genes of the ingredients. https://doi.org/10.6084/m9.Figureshare.24781479 .

Performance of molecular docking

The five active FBR compounds were subjected to molecular docking with the top hub proteins. These compounds demonstrate the highest interaction with hub proteins. The binding scores, amino acid residues, and hydrogen bond distances are represented in Supplementary Table 3 . Quercetin demonstrated the highest binding scores against the AKT1 (−6.8), IL6 (−7.2), and MMP9 (−8.0) hub proteins. Three amino acid residues, A: ARG169, A: MET68, and A: GLU173, with hydrogen bond distances of 2.544, 2.304, and 2.758 Å, respectively, were found against IL6. Isorhamnetin shows better interaction scores against the VEGFA (−8.5) and JUN (−5.3) hub genes than the other FBR compounds. Four hydrogen bond interactions with a strong h-bond distance were found against VEGFA (C: TYR357–2.243 Å; C: HIS415–2.059 Å; B: TYR299–2.918 Å and B: ILE418–2.406 Å). Irisflorentin had a better docking score against VEGFA (−7.4) and three amino acid residues with a strong hydrogen bond distance (Supplementary Table 3 ). Furthermore, ferulic acid demonstrated moderate docking scores against all the hub proteins. The two best hydrogen interactions were found with each hub protein except the IL6 gene. Among these, VEGFA showed a better binding score of −6.9 with the two hydrogen bond interactions and a better bond length (B: ASP323–2.315 Å and B: ILE418–2.970 Å) (Supplementary Fig. 3 , Supplementary Table 2 ). Protocatechuic acid docked with MMP9 showed a better binding score of −7.1 and five different amino acid residues with hydrogen bond distances (Table 2 ). The docking results demonstrated that quercetin, isorhamnetin, Irisflorentin, ferulic acid, and protocatechuic acid are potential regulators of obesity-associated hub genes. The mechanisms through which ferulic acid inhibits α-amylase and α-glucosidase were investigated by Li et al. 37 . These five compounds revealed the highest docking scores and hydrogen bonding interactions out of 17 FBR bioactive metabolites.

Quantification of network pharmacology and molecular docking-guided metabolites

In silico-determined metabolites were detected in the RBR and FBR (1708 and 1741) samples to assess the efficacy of fermentation on polyphenolic content (Fig. 3 ). Since ferulic acid has been shown to improve metabolic health in several ways, it was considered in this investigation. After 48 h of FBR-1741, ferulic acid was significantly higher than in the initial sample and other varieties (RBR-1741: 175.2 µg/g; FBR-1741: 570.2 µg/g). Doses for future investigations based on quantification and metabolites.

Heat map represent the levels of ultra high-performance liquid chromatography (UHPLC) polyphenolic metabolites in raw brown rice compared to fermented brown rice (FBR) varieties, FBR-1708 and FBR-1741; raw brown rice (BR) BR-1708 and BR-1741 at a concentration of 1 mg/mL.

In vivo C. elegans correlation of lifespan and lipid reduction mechanism by FBR extracts with metabolites

High-glucose diets may shorten the lifespan of C. elegans . The mean and maximum longevity (34.5 ± 1.5%) of the FBR-1741 groups were significantly longer than those of the other brown rice groups and those of the negative control groups (30.2 ± 1%). Based on network analysis, we evaluated the lifespan for the FBR-guided top five metabolites from network pharmacology, such as ferulic acid (31.5 ± 1.4), quercetin (28.5 ± 1), isorhamnetin (11.5 ± 09), irisflorentin (22.5 ± 0.8), and protocatechuic acid (6.5 ± 1). The lifespan was prolonged in the ferulic acid-supplemented diet group compared to the other metabolite groups. Ferulic acid, directly associated with a longer lifespan, was also elevated by FBR1741 (Fig. 4a ). Obesity-induced N2 C. elegans consumed OP50 and glucose (PC) groups and died on the 13th day. Our results confirmed those of a previous investigation that suggested that FBR (mixed variety) might increase longevity following a high glucose diet 16 . Many fermented materials demonstrate that lipid metabolism regulates C. elegans longevity by connecting apoptosis, embryonic stem cells, and chromosomal factors. According to Hou et al. 38 , zymolytic grain extract increased longevity dose-dependently compared to the controls. This research shows that extracts from MNL5 FBR-1741 protect against the shorter lifespan caused by hyperglycemia by reducing fat accumulation.

a Lifespan analysis. b C. elegans lipid droplets visualized by Nile-red staining and Oil Red. c mean of fluorescence intensity measured by Image J software; NC-OP50, PC-OP50 + Glucose, DC-OP50 + Glucose + Orlistat, FBR1741-OP50 + Glucose + FBR1741 (1 mg/mL), FA-OP50 + Glucose + FA, QU-OP50 + Glucose + QU, IF-OP50 + Glucose + IF, IH-OP50 + Glucose+IH, PA-OP50 + Glucose + PA. The data are shown as means SEM, with p  < 0.05 indicating statistical significance. https://doi.org/10.6084/m9.Figureshare.24781494 .

The effects of FBR extract on fat accumulation on C. elegans TG and FFA levels

Nile red fluorescence, TG, and FFA assays were used to determine the nematode fat deposition. Nile red fluorescent probe for intracellular lipids and proteins with hydrophobic domains (excitation/emission maxima ∼ 552/636 nm). Figure 4a shows that the worms in the treatment containing more fat ate more glucose than those in the NC treatment, implying that the worms’ diet was a major contributor to their increased fat content. Compared to the FBR-1741 and FA groups, less fat was found (Fig. 4a, b ). Figure 4c demonstrates that FBR and FA inhibited TG in a dose-dependent manner, and the inhibitory effect was comparable to the Nile red and ORO staining findings. The genetic basis of fat metabolism has been extensively investigated using the C. elegans in vivo model. The metabolism, nutrient absorption, and reduction and deposition of fat were all carried out by the intestinal cells of C. elegans . TG enhancement is usually assessed as an endpoint when assessing food intake and energy expenditure. When administered to obese worms, FBR-1741 and FA increased their levels of free fatty acids. Normal, obese, FBR-174, FA, and orlistat worm groups had 3.86, 4.15, 9.23, and 6.59 nmol/mg free fatty acids, respectively (Fig. 5a ). TG content increased in the obese model, then C. elegans treated with 10% glucose and FBR-1741 and FA decreased strongly (Fig. 5b ). There are numerous possible explanations for this observation. The primary sources of free fatty acids are the breakdown of fat stores and dietary sources. Because of this, it is possible that an enhanced flux of free fatty acids in the worms is attributable to an abundance of these metabolites in the FBRs. Plant extract may also stimulate adipose enzymatic metabolism of endogenous fat, increasing plasma-free fatty acids. Compounds in plant extracts, in particular hormone-sensitive lipase, may catalyze the breakdown of adipose tissue triglycerides into fatty acids and glycerol. According to Rodrigues et al. 39 , specific phenolic compounds can promote lipolysis or the breakdown of triglycerides into glycerol and free fatty acids while inhibiting adipose growth and triglyceride production at the cellular level. Following Li et al. 37 , FA was analyzed with Oil Red O to investigate the significance of FA in suppressing fat accumulation. Furthermore, phenolic compounds can impact signaling pathways involved in adipogenesis. FBR-1741 can suppress lipid accumulation in C. elegans and extend its lifespan, according to moderate-to-strong connections between target lipid metabolism genes.

a Fatty acid levels. b Triglyceride level. The data are shown as means SEM, with p  < 0.05 indicating statistical significance. https://doi.org/10.6084/m9.Figureshare.24781503 .

Impact of FBR extracts on gene expression levels of C. elegans

There are many intricately controlled pathways involved in lipid metabolism in C. elegans . This study explored the levels of sterol regulatory element binding protein ( sbp-1 ) and other important transcription factors that stimulate lipid production. In addition, we examined nuclear hormone receptor 49 (nhr-49), a transcription factor that promotes both fatty acid desaturation and β-oxidation, as a functional homolog of human peroxisome proliferator-activated receptors (PPARs) 40 . De novo lipogenesis-involved fatty acid desaturases ( fat-4, fat-5, fat-6 , and fat-7 ) are also positively regulated by nhr-49 41 . In addition, in C. elegans , Daf-16 is a key gene transcription factor that controls the insulin/IGF-1 regulatory system and promotes survival. Daf-16 is a gene primarily responsible for lifespan expansion, while it might also have an impact on fat accumulation in C. elegans 18 . Furthermore, hosl-1 specifies the C. elegans homolog of hormone-sensitive lipase 42 , which triggers the primary rate-limiting process in triglyceride breakdown (Supplementary Fig. 4 ).

Using qPCR, the FBR-1741 and metabolite samples were examined to determine how the fat-controlling genes in C. elegans had changed. As depicted in Figs. 6 and 7 , with the consumption of FBR-1741, the downregulation of sbp-1 , fat-4 , fat-5 , fat-6 , and fat-7 genes and upregulation of hosl-1 and daf-16 by N2 model-related lipid accumulation, lipolysis, and lifespan were observed (Fig. 6a–c ). In our study, Daf-16 activity in neurons enhanced life expectancy by above 20%. In this study, we discovered that C. elegans , like mammals, accumulate fat when they consume excess calories from sugar. The mechanism for fat accumulation in C. elegans is nearly identical to that of mammals, suggesting that this nematode could be a time-saving and cost-effective alternative for investigating fat metabolism.

a Expression levels of genes involved in fat synthesis (FAT-4, FAT-6, FAT-7, and SBP-1). b Expression levels of genes involved in lipolysis (HOSL1). c Expression levels of genes involved in lifespan (Daf-16). d Heat map for the fatty acid metabolite profile. e Fat synthesis is responsible for fatty acid metabolites. The data are shown as means SEM, with p  < 0.05 indicating statistical significance. https://doi.org/10.6084/m9.Figureshare.24781509 .

This study provides an in-depth analysis of untargeted metabolomics and network pharmacology, highlighting the potential of fermented brown rice in enhancing anti-obesity efficacy. Through comprehensive research, we explore the complex interactions and biochemical pathways influenced by fermented brown rice, offering new insights into its therapeutic potential.

Effect of FBR extracts on fatty acid profiles of C. elegans

Human health is significantly affected by fatty acids, which consist of both saturated and unsaturated fatty acids. Saturated fatty acids are found primarily in palmitic, stearic, and arachidic acids; an excess of such acids can lead to atherosclerotic and cardiovascular disease 43 . The synthesis of unsaturated fatty acids depends on the genes that encode stearoyl-CoA desaturase (SCDs), such as fat-4, fat-5, fat-6, and fat-7. According to research, preventing the expression of fat-6 and fat-7, which encode the stearoyl CoA desaturating enzyme responsible for desaturating octadecyl saturated fatty acid, may minimize nematode fat accumulation 44 . Changes in metabolite levels occur in nearly all metabolic diseases. Several digestive enzymes that convert acetyl CoA to malonyl CoA and C16 palmitate regulate fat synthesis in C. elegans . This fluctuation may be restored to normal with the adoption of a nutritious daily diet (Supplementary Fig. 5a–c ). Thus, this approach was used to show how metabolic alterations caused by obesity can be reversed by eating FBR-1741. Figure 6d shows that obese-induced FBR-1741 and FA treatment dramatically increased saturated fatty acid components, including palmitic acid (C16:0), stearic acid (C18:0), oleic acid (18:1), arachidic acid (20:4), eicosadienoic acid (20:5), and α-linoleic acid (PUFA) (Fig. 6d , Supplementary Fig. 5d, e ). In addition, Qi et al. 45 demonstrated that the ω-3 fatty acid α-linolenic acid (ALA) is able to increase the lifespan of C. elegans . Other treatments, such as positive control and metabolite diet groups, resulted in a significant decrease in saturated fatty acids. Serine, arginine, histidine, threonine, methionine, and glycolic acids also increased in FBR-1741- and FA-treated groups. According to Edwards et al. 46 , the levels of amino acids such as leucine, histidine, methionine, and tryptophan could significantly influence the lifespan of C. elegans . This finding provided further confirmation of our prior results, showing an increase in free fatty acid in worms after supplementation with FBR-1741, including metabolites for C. elegans . Results from both gene expression analysis and metabolomics assessment validate our prior finding that administering FBR-1741 and an FA-supplemented diet denoted that worm dramatically increased their lifespan (Supplementary Fig. 5f ) and decreased lipid accumulation.

In this research, nine different types of brown rice were fermented with P. acidilactici MNL5 KCTC15156BP. Among the nine varieties, FBR-1741 had the strongest lipase inhibition, antioxidant activity, and phenolic phytochemical identification. In our previous investigation, we evaluated the biological activities of raw brown rice. In this study, we integrated omics data following systems biology principles to discover novel obesity therapeutic targets. However, FBR-1741 refers to specified phenolic compounds with potent lipase inhibition and antioxidant activity. Based on pathway enrichment studies, enhanced polyphenols may interfere with many pathways, including those implicated in obesity and obesity-related disorders, which may explain the possible anti-obesity impacts of FBR1741. The network-based pharmacological investigation of FBR-1741 found 17 compounds and 132 obesity-related target genes. Our results in the C. elegans N2 obese-induced paradigm reveal that FBR-1741 with ferulic acid has a higher survival rate and is a valuable indicator for assessing lipid reduction beyond dietary efforts. Ferulic acid was increased by FBR-1741, which may have a causal relationship with increased longevity and decreased lipid levels. In addition, FBR-1741 prolonged C. elegans lifespan and reduced fat accumulation, validating gene expression for fatty acid metabolites. However, additional research is needed to explain the fermented material for the in vivo C. elegans metabolomic study. This research provides a better comprehension of the synergistic effects of microorganisms. In addition, the findings of this study will be useful for future research using obesity models in mice to investigate the effect of FBR-1741 on gut microbiota and obesity correlation studies. In addition, we can use these considerations to develop a fermented brown rice product to combat obesity.

Procurement of chemicals and plant materials

Experimental medium and chemicals were purchased from Daejung Chemicals and Metals Co., Ltd, Korea. A PicoSens TM Triglyceride and Free Fatty Acid Assay Kit was purchased from BIOMAX in Seoul, Korea. Our study used METLIN and the Metabolomics Workbench to assist us in determining the classification of polyphenolics. Brown rice was collected from the Rural Development Administration (RDA) of the Republic of Korea. After the samples were powdered with an electric grinder, the materials were filtered using a sieve size of 40 mm to eliminate dust and debris 47 .

Bacterial growth and optimization of brown rice fermentation

The brown rice fermentation medium was mixed on sterilized rice powder with distilled water (1:6 ratio). The fermentation of brown rice was autoclaved for 15 min at 121 °C before lactic acid bacteria were inoculated. The P. acidilactici MNL5 (KCTC15156BP) strain (2 × 10 7  CFU/mL) was transferred and grown for 48 h at 37 °C with agitation at 200 rpm. The samples were freeze-dried and kept at −20 °C for further investigation.

Solvent extraction method

Our study used METLIN and the Metabolomics Workbench to assist us in determining the classification of polyphenolics. A total of 50 g of fermented rice powder was placed in an electric shaker and mixed with 100 mL of 70% ethanol (1:20 w/v) at ~50 °C for ~4 h. The extracts were centrifuged at 4000× g for 10–15 min (Hanil Science Industrial, Incheon, Korea). This process was repeated three times. The supernatant’s ethanol content was evaporated at 50–55 °C and freeze-dried. Then, the samples were stored at −20 °C. The samples were prepared into a standard liquid sample with 1 mg/mL of concentration 47 .

In vitro anti-obesity efficacy by using pancreatic lipase inhibition assay

The lipase inhibition assay of the FBR samples was performed in a 36-well plate with minor modifications 16 . The percentage of inhibition of lipase was used to express the results. Lipase inhibition with and without substrate was determined using fluorescence readings. The results are provided as a percentage of inhibition of 1 mg/mL of the samples.

Total phenolic content (TPC) and total flavonoid content (TFC)

The FBR samples were evaluated for TPC and TFC utilizing a 36-well plate, following the methodology described by Glorybai et al. 48 . For the TPC, 200 µL Folin–Ciocalteu reagent was added to 100 µL sample extracts, standard, or 95% (v/v) methanol as blank. Following vertexing, the mixture was incubated at an ambient temperature for 2 h. After adding 800 µL of 700 mM sodium carbonate to each mixture, absorbance was measured at 765 nm.

For the TFC, 250 µL sample extracts were pipetted into microplate wells, followed by 75 µL N a NO 2 (50 g L −1 ) and 1 mL distilled water. After 5 min of settling, 75 µL AlCl 3 (100 g L −1 ) was added. A total of 500 µL of 1 M NaOH and 600 µL distilled water were added and incubated for 6 min after letting the reaction mixture settle. After 30 s of shaking, a Spectra-Max i3 plate reader (Molecular Devices Korea, LLC, Seoul, Korea) measured absorbance at 510 nm. TPC and TFC results were reported in gallic acid and catechin equivalent per 100 g (mg/100 g, DW).

DPPH, ABTS, and FRAP radical scavenging effects

The FBR sample was examined with DPPH, ABTS, and FRAP on a 36-well plate using the previously described process with minimal changes 49 .

In brief, 100 μL of sample extract, standard (Trolox), or blank (methanol) was mixed with a freshly prepared 500 μM DPPH solution in a 24-well microplate. Then, this was incubated at room temperature for 30 min. Absorbance was measured at 515 nm. The baseline curve was the Trolox concentration plot with DPPH radical scavenging activity.

ABTS stock solution was prepared by mixing 2.45 mmol/L potassium persulfate with 7 mmol/L ABTS solution (1:1, v/v) in the dark for 12–16 h at room temperature. The ABTS + reagent was diluted with methanol until it achieved 0.700 ± 0.020 absorbance at 734 nm wavelength. After diluting 100 μL of extracts or standards with 1 mL of ABTS + solution, absorbance was measured at 734 nm.

To prepare the FRAP reagent, 0.1 mL of extract was diluted with 3.9 mL of acetate buffer (50 mL, 0.3 M, pH 3.6), TPTZ solution (10 mM in 40 mM HCl), and FeCl 3 ·6H 2 O (5 mL, 20 mM) for 10 min at 37 °C. Absorbance was measured at 593 nm wavelength. The absorbance was measured with the SpectraMax i3 plate reader (Molecular Devices Korea, LLC). DPPH, ABTS, and FRAP values were expressed as mg Trolox equivalent per 100 g of sample (mg Trolox equiv./100 g, DW) using the following formula:

where Ae represents the extract or standard absorbance; Ac represents the blank sample absorbance.

Identification and evaluation of untargeted metabolites in FBR varieties using UHPLC-Q-TOF-MS/MS

Characterizing untargeted metabolites using the UHPLC-Q-TOF-MS/MS method: The filtered samples were added to an autosampler vial for analysis using 0.22 mm Micropore injection filters from Merck KGaA, Darmstadt, Germany, following our prior studies 16 . After setting the Q-TOF-MS/MS to the negative mode, the mass range was set to 100–1000, and the precision was set to 5000. For full mass spectra, 1.45 kV and 30 V capillary and cone voltages were utilized. N 2 flowed at 900 L/h, while helium (the cone gas) flowed at 45 L/h. MS/MS spectra were obtained at 15, 20, and 30 V collision energies with N 2 at 250 °C and the ion source at 120 °C. Untargeted metabolites were found through a comparison of retention time (RT) along with spectral profile spectral databases, such as XCMS Online (METLIN; https://metlin.scripps.edu ) and the Metabolomics Workbench ( https://www.metabolomic-micsworkbench.org ).

Correlation and identification of bioactive metabolites by network pharmacology in fermented brown rice (FBR) for anti-obesity

The bioactive components in FBR were identified by employing UHPLC-Q-TOF-MS/MS. The resultant metabolites were subsequently assessed by the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database for assimilatory characteristics according to drug-selection criteria such as oral bioavailability (OB) and drug-likeness (DL). Oral bioavailability summarizes medicines’ attributes of absorption, distribution, metabolism, and excretion (ADME) and their consumption in the blood flow 50 . The chemical data for each ingredient, including their chemical structures, molecular formula, and biological information, were acquired using the Pub Chem and Drug Bank databases.

Obesity-related gene target screening

Obesity-related gene target data were obtained from TCMSP, DisGeNET, and GeneCards 50 . In addition, the aforementioned electronic databases were explored using the search term “obesity” to find the disease of interest and its associated genes.

Functional-enrichment analysis

The network of protein‒protein interactions (PPI) was constructed using STRING 11.0 and was estimated toward a high confidence level of 70% identity (0.700). The enrichment analyses, Gene Ontology (GO), and KEGG Pathway were performed to develop the biological process (BP), molecular function (MF), and cellular components (CC) of disease target proteins 50 , 51 . Moreover, networks of hub-gene-associated targets, pathway interactions, and target‒gene interactions with potential compounds were constructed using the Cystoscope tool 50 .

In silico molecular docking

The tertiary molecular structures of the top-hit hub genes and secondary metabolic products were obtained from the Drug Bank (a pharmaceutical database) and Data Bank ( https://www.rcsb.org ). Eliminating hydrogen from the receptor and omitting water molecules generated protein molecular structures. Flexible docking was used to evaluate molecular interactions between top-hit hub proteins and ligands using AUTODOCK VINA, and binding pockets were autonomously identified. The Discovery Studio software was used to determine the molecular binding from a two-and three-dimensional viewpoint. The docking scores, bond lengths, and all interactions were recorded 50 .

Impact of the FBR-supplemented C. elegans model on the lipid reduction mechanism

Caenorhabditis elegans (N 2 wild type) and Escherichia coli OP50 were acquired from the Caenorhabditis Genetics Center (CGC), University of Minnesota, Minneapolis. The growth, synchronization, and maintenance of C. elegans took place at 20 °C. Nematode growth medium (NGM) plates contain 5-fluorodeoxyuridine (FUDR, 140 mM) and were inoculated at 37 °C with 10% glucose with FBR-1741 (1 mg/plate) and a different metabolite diet. After 4 h, worms were moved to a fresh NGM 90 mm Petri dish with a targeted metabolite diet 52 . The dosage was used guided by UHPLC quantification of FBR-1741 (1 mg/ml): quercetin (0.19 µg/plate), isorhamnetin (0.18 µg/plate), irisflorentin (0.18 µg/plate), ferulic acid (0.57 µg/plate), and protocatechuic acid (0.19 µg/plate).

Impact of FBR and bioactive metabolites on the C. elegans lifespan

FBR-1741 samples were evaluated by our previous procedure, and C. elegans longevity was evaluated 16 . The nematode was maintained, developed, and synchronized with bleached gravid hermaphrodites (1:1 ratio of NaOH and sodium hypochlorite). In the bleach solution added, vortexed with eggs, and centrifuged at 1500 rpm for 2 min. After adding an equivalent buffer volume, M9 buffer was used to wash the egg pellet (3 g KH 2 PO 4 , 6 g Na 2 HPO 4 , 5 g NaCl, 1 mL 1 M MgSO 4 , H 2 O to 1 L). The L1-stage worms were transferred to plates of nematode growth medium (NGM) containing E. coli OP50 to be fed to the worms at a temperature of 20 °C. This study incubated 50 μL of OP50 in LB broth on a 60 mm NGM Petri dish (FUdR) at 37 °C for 24 h. FBR, a diet with specific metabolites, and OP50 plates were given to 50 L4-stage C. elegans . Each plate was placed in an incubator at 20 °C, and every 24 h, dead worms were enumerated. Worms were moved to new NGM plates containing the specified diet every three days. To determine the effect of glucose on FBR, the average lifespan of OP50 nematodes was evaluated.

Lipid accumulation in C. elegans : a fluorescence microscopy study

Nile red and Oil Red dyes were used for the lipid reduction experiments. In this study, L4-stage worms were rinsed with M9 buffer. Furthermore, after adding a drop of Nile red (0.05 μg/mL) solution, the worms were incubated for 30 min and rinsed twice with 25% ethanol. In addition, 60% isopropanol was added for 5 min, and L4 worms were collected in 15 mL centrifuge tubes. The worm pellet was transferred confocal dish under the fluorescence microscope (Olympus CKX53, Tokyo, Japan) 52 . Furthermore, 0.05 μg/mL of Oil Red O solution was used in accordance with the above procedure. Individual worms were photographed using an Olympus SZ 61 zoom stereomicroscope and an HK3.1 CMOS camera on worm pellets to be treated with ORO and subsequently transferred and analyzed. Lipids stained were predominantly present in the intestine, and the anterior region was much brighter than the posterior region. The area used for integrating fluorescence density measurements was chosen from the intestinal anterior front to the vulva. Six L4 worms were randomized for analysis. For the image J analysis, the images were captured at ×20 magnification.

Determination of triglycerides and free fatty acids

Triglyceride (TG) and free fatty acids (FFA) analysis measures the effects on lipid levels of different FBRs with metabolites in mixed diets in C. elegans . TG and FFA levels were measured by measuring C. elegans at 50% of the lifespan for treatments. Triglycerides and FFA content were determined using a commercially available colorimetric assay kit (Biomax, Seoul, Korea), following the manufacturer’s guidelines.

Gene expression profile of the FBR-1741 and metabolite-supplemented C. elegans model

Worms were collected from a 90 mm Petri dish on the treatment plate at 20 °C on the 7th day of 50% lifespan. Each treatment collected 1000 worms, washed with M9 buffer, and centrifuged at 5000 rpm for 5 min. The worm pellet was added, together with TRIzol reagent (TRIzol® Thermo Fisher Scientific, Inc., Middletown, VA), followed by lysing in 2 mL tubes with Lysing Matrix Z beads (MP Biomedicals, Santa Ana, CA, USA) was used to extract total RNA from worm samples. Following the manufacturer’s instructions, a high-capacity cDNA reverse transcription kit (Thermo Fisher Scientific, Inc., Middletown, VA) and a standard thermal cycler (Bio-Rad Laboratories Inc., Hercules, CA) produced cDNA templates. The 260/280 absorbance ratio determined the RNA purity. StepOnePlus Real-Time PCR (Applied Biosystems, Foster City, CA) and GoTaq® qPCR Master Mix kit (Promega) were used to measure gene expression. Each reaction contained 10 μL of GoTaq® qPCR Master Mix kit (A600A), 2 μL of cDNA (10 ng μL −1 ), 0.4 μL of each primer (10 pg μL −1 ), and 7 μL of double-distilled water. The 2 − ∆∆ CT technique standardized gene expression levels to the act-1 primer (Supplementary Table 4 ).

Worm sample preparation for metabolomics analysis

Approximately 1000 worms were collected for each treatment, washed in M9 buffer, and centrifuged at 5000 rpm for 5 min. The worm pellet was added to a Lysing Matrix Z (MP Biomedicals, Bio-Connect, The Netherlands) vial containing 1 mL of 70% methanol, and the mixture was homogenized. The previously mentioned metabolomic analysis technique was carried out on the supernatant collected following centrifuging the samples for 10 min at 10,000 rpm and filtering through a 0.45 m membrane filter.

Statistical analysis

All evaluations were carried out at least three times, and the results are expressed as the mean ± SD. Microsoft Excel 365 enabled the acquisition of pertinent graphs. The tertiary structures of the top hit hub proteins and derived chemical compounds were retrieved from the protein data bank ( https://www.rcsb.org/ ) and DrugBank (a familiarity foot of the pharmaceutical repository) ( https://go.drugbank.com/ ). The protein structures were prepared based on the addition of hydrogen molecules and the removal of water molecules in the receptor. The molecular docking studies were performed with the selected top-hit hub proteins and ligands using the AutoDock Vina 4.2.6. The empirical formula was applied to find chemicals from PubChem (accessed on March 12, 2022) and ChemSpider (accessed on March 20, 2022). Heatmaps were generated by the ClustVis programs ( https://biit.cs.ut.ee/clustvis/accessed on May 16, 2023) 16 .

Reporting summary

Further information on research design is available in the Nature Research Reporting Summary linked to this article.

Data availability

We declare that all data related to this study are included in this paper and its supplementary information.

Organization, W. H. World Obesity Day 2022—Accelerating Action to Stop Obesity (World Health Organization, Geneva, Switzerland, 2022).

Mohan, V. et al. Hurdles in brown rice consumption. Brown Rice 255–269 (2017). https://doi.org/10.1007/978-3-319-59011-0_15 .

Tyagi, A. et al. Limosilactobacillus reuteri fermented brown rice: a product with enhanced bioactive compounds and antioxidant potential. Antioxidants 10 , 1077 (2021).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Obafemi, Y. D. et al. African fermented foods: overview, emerging benefits, and novel approaches to microbiome profiling. npj Sci. Food 6 , 15 (2022).

Article   PubMed   PubMed Central   Google Scholar  

Zhang, J. et al. Effects of L. plantarum dy-1 fermentation time on the characteristic structure and antioxidant activity of barley β-glucan in vitro. Curr. Res. Food Sci. 5 , 125–130 (2022).

Yang, J. et al. Mathematical model of Chlorella minutissima UTEX2341 growth and lipid production under photoheterotrophic fermentation conditions. Bioresour. Technol. 102 , 3077–3082 (2011).

Article   CAS   PubMed   Google Scholar  

Jemil, I. et al. A peptidomic approach for the identification of antioxidant and ACE-inhibitory peptides in sardinelle protein hydrolysates fermented by Bacillus subtilis A26 and Bacillus amyloliquefaciens An6. Food Res. Int. 89 , 347–358 (2016).

Wilson, T. A., Nicolosi, R. J., Woolfrey, B. & Kritchevsky, D. Rice bran oil and oryzanol reduce plasma lipid and lipoprotein cholesterol concentrations and aortic cholesterol ester accumulation to a greater extent than ferulic acid in hypercholesterolemic hamsters. J. Nutr. Biochem. 18 , 105–112 (2007).

Gao, Y. et al. Similarities and differences among the responses to three chlorinated organophosphate esters in earthworm: evidences from biomarkers, transcriptomics and metabolomics. Sci. Total Environ. 815 , 152853 (2022).

Hasin, Y., Seldin, M. & Lusis, A. Multi-omics approaches to disease. Genome Biol. 18 , 1–15 (2017).

Article   Google Scholar  

Reza, M. S. et al. Bioinformatics screening of potential biomarkers from mRNA expression profiles to discover drug targets and agents for cervical cancer. Int. J. Mol. Sci. 23 , 3968 (2022).

Tai, Y. et al. Identification of hub genes and candidate herbal treatment in obesity through integrated bioinformatic analysis and reverse network pharmacology. Sci. Rep. 12 , 17113 (2022).

Anand Mariadoss, A. V., Krishnan Dhanabalan, A., Munusamy, H., Gunasekaran, K. & David, E. In silico studies towards enhancing the anticancer activity of phytochemical phloretin against cancer drug targets. Curr. Drug Ther. 13 , 174–188 (2018).

Article   CAS   Google Scholar  

Velusamy, S., Husain, S. A. M., Alarifi, S., Arokia, V. A. M. & Muthusamy, J. Screening potential inhibitor from actinomycetes for dihydrofolate reductase of Staphylococcus aureus –In vitro and in silico studies. J. King Saud. Univ.-Sci. 35 , 102762 (2023).

Bouyanfif, A., Jayarathne, S., Koboziev, I. & Moustaid-Moussa, N. The nematode Caenorhabditis elegans as a model organism to study metabolic effects of ω-3 polyunsaturated fatty acids in obesity. Adv. Nutr. 10 , 165–178 (2019).

Barathikannan, K. et al. Untargeted metabolomics of fermented onion ( Allium cepa L.) using UHPLC Q-TOF MS/MS reveals anti-obesity metabolites and in vivo efficacy in Caenorhabditis elegans. Food Chem. 404 , 134710 (2023).

Yue, H. et al. Effects of α-linolenic acid intake on blood lipid profiles: a systematic review and meta-analysis of randomized controlled trials. Crit. Rev. Food Sci. Nutr. 61 , 2894–2910 (2021).

Huayta, J., Crapster, J. P. & San-Miguel, A. Endogenous DAF-16 spatiotemporal activity quantitatively predicts lifespan extension induced by dietary restriction. Commun. Biol. 6 , 203 (2023).

Kniazeva, M., Crawford, Q. T., Seiber, M., Wang, C. Y. & Han, M. Monomethyl branched-chain fatty acids play an essential role in Caenorhabditis elegans development. PLoS Biol. 2 , 257 (2004).

Moreno, D. A., Ilic, N., Poulev, A. & Raskin, I. Effects of Arachis hypogaea nutshell extract on lipid metabolic enzymes and obesity parameters. Life Sci. 78 , 2797–2803 (2006).

Wang, Z., Ge, S., Li, S., Lin, H. & Lin, S. Anti-obesity effect of trans-cinnamic acid on HepG2 cells and HFD-fed mice. Food Chem. Toxicol. 137 , 111148 (2020).

Dai, T. et al. Protein–polyphenol interactions enhance the antioxidant capacity of phenolics: analysis of rice glutelin–procyanidin dimer interactions. Food Funct. 10 , 765–774 (2019).

Janarny, G. & Gunathilake, K. Changes in rice bran bioactives, their bioactivity, bioaccessibility and bioavailability with solid-state fermentation by Rhizopus oryzae . Biocatal. Agric. Biotechnol. 23 , 101510 (2020).

Ghasemzadeh, A., Jaafar, H. Z., Juraimi, A. S. & Tayebi-Meigooni, A. Comparative evaluation of different extraction techniques and solvents for the assay of phytochemicals and antioxidant activity of Hashemi rice bran. Molecules 20 , 10822–10838 (2015).

Ilowefah, M., Bakar, J., Ghazali, H. M. & Muhammad, K. Enhancement of nutritional and antioxidant properties of brown rice flour through solid‐state yeast fermentation. Cereal Chem. 94 , 519–523 (2017).

Prior, R. L., Wu, X. & Schaich, K. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. J. Agric. Food Chem. 53 , 4290–4302 (2005).

Georgiev, V. G. et al. Antioxidant activity and phenolic content of betalain extracts from intact plants and hairy root cultures of the red beetroot Beta vulgaris cv. Detroit dark red. Plant Foods Hum. Nutr. 65 , 105–111 (2010).

Kuppusamy, P., Ilavenil, S., Hwang, I. H., Kim, D. & Choi, K. C. Ferulic acid stimulates adipocyte-specific secretory proteins to regulate adipose homeostasis in 3T3-L1 adipocytes. Molecules 26 , 1984 (2021).

Luo, Z. et al. Ferulic acid prevents nonalcoholic fatty liver disease by promoting fatty acid oxidation and energy expenditure in c57bl/6 mice fed a high-fat diet. Nutrients 14 , 2530 (2022).

Jung, U. J., Lee, M.-K., Park, Y. B., Jeon, S.-M. & Choi, M.-S. Antihyperglycemic and antioxidant properties of caffeic acid in db/db mice. J. Pharmacol. Exp. Ther. 318 , 476–483 (2006).

Lee, C. W. et al. 3-O-Glucosylation of quercetin enhances inhibitory effects on the adipocyte differentiation and lipogenesis. Biomed. Pharmacother. 95 , 589–598 (2017).

Loebig, M. et al. Evidence for a relationship between VEGF and BMI independent of insulin sensitivity by glucose clamp procedure in a homogenous group healthy young man. PLoS ONE 5 , e12610 (2010).

Robciuc, M. R. et al. VEGFB/VEGFR1-induced expansion of adipose vasculature counteracts obesity and related metabolic complications. Cell Metab. 23 , 712–724 (2016).

Shearin, A. L., Monks, B. R., Seale, P. & Birnbaum, M. J. Lack of AKT in adipocytes causes severe lipodystrophy. Mol. Metab. 5 , 472–479 (2016).

Popko, K. et al. Proinflammatory cytokines Il-6 and TNF-α and the development of inflammation in obese subjects. Eur. J. Med. Res. 15 , 1–3 (2010).

Wang, Z. Y. et al. The mechanisms of baicalin ameliorate obesity and hyperlipidemia through a network pharmacology approach. Eur. J. Pharmacol. 878 , 173103 (2020).

Li, H. et al. Ferulic acid supplementation increases lifespan and stress resistance via insulin/IGF-1 signaling pathway in C. elegans . Int. J. Mol. Sci. 22 , 4279 (2021).

Hou, L., Jiang, M., Guo, Q. & Shi, W. Zymolytic grain extract (ZGE) significantly extends the lifespan and enhances the environmental stress resistance of Caenorhabditis elegans . Int. J. Mol. Sci. 20 , 3489 (2019).

Rodrigues, C. F. et al. Salvia hispanica L. (chia) seeds oil extracts reduce lipid accumulation and produce stress resistance in Caenorhabditis elegans . Nutr. Metab. 15 , 83 (2018).

Gilst, M. R. V., Hadjivassiliou, H., Jolly, A. & Yamamoto, K. R. Nuclear hormone receptor NHR-49 controls fat consumption and fatty acid composition in C. elegans . PLoS Biol. 3 , e53 (2005).

Mack, H. I., Kremer, J., Albertini, E., Mack, E. K. & Jansen-Dürr, P. Regulation of fatty acid desaturase-and immunity gene-expression by mbk-1/DYRK1A in Caenorhabditis elegans . BMC Genom. 23 , 25 (2022).

Kumarasingha, R. et al. Transcriptional alterations in Caenorhabditis elegans following exposure to an anthelmintic fraction of the plant Picria fel-terrae Lour. Parasites Vectors 12 , 9 (2019).

Toth, P. P. Triglycerides and atherosclerosis: bringing the association into sharper focus ∗ . J. Am. Coll. Cardiol. 77 , 3042–3045 (2021).

Shen, P., Yue, Y., Zheng, J. & Park, Y. Caenorhabditis elegans : a convenient in vivo model for assessing the impact of food bioactive compounds on obesity, aging, and Alzheimer’s disease. Annu. Rev. Food Sci. Technol. 9 , 1–22 (2018).

Article   PubMed   Google Scholar  

Qi, W. et al. The ω‐3 fatty acid α‐linolenic acid extends Caenorhabditis elegans lifespan via NHR‐49/PPAR α and oxidation to oxylipins. Aging Cell 16 , 1125–1135 (2017).

Edwards, C. et al. Mechanisms of amino acid-mediated lifespan extension in Caenorhabditis elegans . BMC Genet. 16 , 1–24 (2015).

Tyagi, A. et al. Quantification of amino acids, phenolic compounds profiling from nine rice varieties and their antioxidant potential. Antioxidants 11 , 839 (2022).

Glorybai, L., Kannan K, B., Arasu, M. V., Al-Dhabi, N. A. & Agastian, P. Some biological activities of Epaltes divaricata L.—an in vitro study. Ann. Clin. Microbiol. Antimicrob. 14 , 11 (2015).

Tyagi, A. et al. Antioxidant activities of novel peptides from Limosilactobacillus reuteri fermented brown rice: a combined in vitro and in silico study. Food Chem. 404 , 134747 (2023).

Vinothkanna, A., Prathiviraj, R., Sivakumar, T. R., Ma, Y. & Sekar, S. GC–MS and network pharmacology analysis of the ayurvedic fermented medicine, Chandanasava, against chronic kidney and cardiovascular diseases. Appl. Biochem. Biotechnol. 195 , 2803–2828 (2023).

Sivakumar, T. R. et al. Network pharmacology based analysis of Astragalus propinquus components for the treatment of rheumatoid arthritis and diabetes. South Afr. J. Bot. 139 , 92–105 (2021).

Barathikannan, K. et al. Anti-obesity efficacy of Pediococcus acidilactici MNL5 in Canorhabditis elegans gut model. Int. J. Mol. Sci. 23 , 1276 (2022).

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Acknowledgements

This research was financially supported by the Ministry of SMEs and Startups (MSS), Korea, under the “Regional Specialized Industry Development Program (R&D, Grant number S3272987)” supervised by the Korea Technology and Information Promotion Agency for SMEs (TIPA).

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Ramachandran Chelliah, Akanksha Tyagi, Selvakumar Vijayalakshmi, Min-Jin Lim & Deog- Hwan Oh

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Barathikannan, K., Chelliah, R., Vinothkanna, A. et al. Untargeted metabolomics-based network pharmacology reveals fermented brown rice towards anti-obesity efficacy. npj Sci Food 8 , 20 (2024). https://doi.org/10.1038/s41538-024-00258-x

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Nutritional and functional properties of coloured rice varieties of South India: a review

• Rathna Priya T. S. 1 ,
• Ann Raeboline Lincy Eliazer Nelson 1 ,
• Kavitha Ravichandran 1 &
• Usha Antony 1  

Journal of Ethnic Foods volume  6 , Article number:  11 ( 2019 ) Cite this article

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Rice is a major cereal food crop and staple food in most of the developing countries. India stands second in the production of rice next to China. Though almost 40,000 varieties of rice are said to exist, at present, only a few varieties are cultivated extensively, milled and polished. Even if white rice is consumed by most people around the world, some specialty rice cultivars are also grown. These include the coloured and aromatic rice varieties. The nutritional profile of the specialty rice is high when compared to the white rice varieties. The coloured rice, which usually gets its colour due to the deposition of anthocyanin pigments in the bran layer of the grain, is rich in phytochemicals and antioxidants. Rice bran, a by-product of the rice milling industry is under-utilised, is rich in dietary fibre which finds application in the development of functional foods and various other value-added products. Thus, more focus on specialty rice and its by-products will not only save it from becoming extinct but also lead a step forward towards nutrition security of the country as they are abundant in vitamins, minerals and polyphenols.

Introduction

Rice is a major cereal crop consumed as a staple food by over half of the world’s population. Consumption of rice is very high in developing countries and nations in Asia. Almost 95% of the rice production is done in Asian countries and about half of the world’s population consumes it. The cultivation of rice ranks third in the production of agricultural commodity next to sugarcane and maize. It is the predominant dietary energy source of 17 countries in Asia and the Pacific, 9 countries in North and South America and 8 countries in Africa. India is one of the major centres for rice production. The area for rice cultivation in India comprises about 43,388,000 hectares of land [ 1 ] and rice contributes to 780 and 689 kcal/capita/day of the food supply in Asia and India, respectively. Furthermore, India is one of the largest countries in terms of energy consumption from agriculture and rice comprises a major part of it [ 2 ].

Rice is rich in genetic diversity, with thousands of varieties grown throughout the world and India is home to 6000 varieties, at present. Originally, India had more than 110,000 varieties of rice until 1970, which were lost during the Green Revolution with its emphasis on monoculture and hybrid crops [ 3 ]. Paddy comes in many different colours, including brown, red, purple and even black. The colourful varieties of rice are considered valuable for their health benefits. The unpolished rice with its bran has high nutrient content than milled or polished white rice. However, rice consumers prefer to consume polished white rice, despite the fact that brown rice contains valuable nutrient content [ 4 ]. A detailed analysis on the nutrient content of rice suggests that the nutrition value varies depending upon several factors such as the strain or variety (i.e. white , brown , red and black /purple), nutrient quality of the soil in which rice is cultivated, the degree of milling and the method of preparation before consumption.

Origin and spread of rice

Oryza sativa , the dominant rice species, is a member of the Poaceae family. Historically, rice was cultivated widely in the river valleys of South and Southeast Asia 10,000 years ago [ 5 ] and it is believed to have originated probably in India. Domestication of rice in India is mainly attributed to the Indus valley civilization c. 3000–1500 BC [ 6 ]; however, the evidence of rice cultivation in India has been pushed to 4000 years ahead with the discovery of rice grains and early pottery found in the site of Lahuradewa, Uttar Pradesh, situated in the middle Ganges plains dating to c. 6409 BC [ 7 , 8 ].

Rice is highly adaptable to its environment of growth and this is evident from the fact that it is grown in north-eastern parts of China at latitude 53°N, on the equator in central Sumatra, and at 35°S in New South Wales, Australia. In India, it is grown below sea level in Kerala; most rice-growing areas are present at or near sea level and also, at elevations above 2000 m in Kashmir. Today, rice is cultivated in all parts of the world except Antarctica [ 9 ].

Importance of rice in India

India ranks second in the production of rice in the world next to China, accounting for 22.5% of overall world rice production. Rice is India’s pre-eminent crop and is the staple food of the people of the eastern and southern parts of the country. Apart from being nutritionally rich, rice has greater significance in India and holds great spiritual and ritual importance. As per Indian tradition, rice is revered as a potent symbol of auspiciousness, prosperity and fertility because of its life-sustaining qualities. Several rituals involving rice are performed during different occasions and festivals. In Tamil Nadu, kolam , a kind of geometric pattern, is drawn using rice flour at the threshold of the houses by women before sunrise. Rice also plays a vital role in wedding ceremonies in India. Dhanpan is a ritual wherein the family of bridegroom sends paddy, betel and/or turmeric to the house of the bride [ 10 ]. Rice mixed with turmeric is thrown on the couples during the wedding ceremony as a symbol of prosperity, eternity, continuity and fertility. The father of the bride organises a feast called Bhat (means, boiled rice) for the family and relations of the bridegroom [ 10 ]. The brides throw five handfuls of rice before leaving their parents’ home after the wedding to wish prosperity and wealth and remain with the family members. The bride enters her new home by pushing a glass or a jar full of rice while, rice is the first food offered to the bridegroom by the bride after marriage. In Tamil Nadu, the groom is offered a special variety of rice named Maappillai Samba to improve fertility [ 11 ]. Rice also plays a vital role during the baby shower function, named godh bharai in North India, valaikaapu in Tamil Nadu and seemandham in Kerala; on the event of birth; at the time of giving first solid food to the baby that is 6 or 7 months old; and during puberty in Kerala and Tamil Nadu. Flattened rice made from a variety called Thavala Kannan is given as offering in Kerala.

Rice also plays a prominent role in cultural celebrations of India, such as the festivals are based on sowing of seeds in the paddy field, transplanting the saplings in the fields, removal of weeds from the fields, harvesting of paddy, thrashing of paddy and storage of paddy [ 10 ]. The harvest festivals include Thai Pongal celebrated in the Tamizhian calendar month of Thai (falls in the month of January) in Tamil Nadu; Onam celebrated in the Malayalam month of Chingam (falls in the month of August or September) and Sankranti in Andhra Pradesh and Telangana, Makar Sankranti in Karnataka, Na-Khuwa Bhooj in rural Assam, Nabanna in West Bengal, and Nua khia or Navanna in Odisha; and Bihu in Assam celebrates the harvest of paddy. Thus, rice has not only shaped the history, culture, diet and economy of people but also the growth stage of the rice crop marks the passage of time and season. In India, rice is considered the root of civilization [ 12 ].

Production and market demand for rice varieties

Rice is a fundamental food in many cultural cuisines around the world. According to Ricepedia, more than 90% of production and consumption of rice in the world occur in Asia and the current share in global rice consumption is around 87%. In African countries, per capita consumption continues to increase than production [ 13 ]. The volume of international rice trade has increased almost sixfold, from 7.5 million tonnes annually in the 1960s to an average of 44.2 million tonnes during 2015–2016.

Based on the global market scenario with respect to rice, the production has increased slightly with years. The use of rice as food remains predominant compared to feed and other uses. The supply and utilisation of rice have also increased slightly (Table  1 ).

Similarly, rice is a major cereal crop and is consumed as a staple food by the majority of the population in India. India is one of the major centres for the production of rice. Both the Himalayan red rice and the Assam red rice find their place in international trade. The production of rice, wheat and maize has grown steadily over this period and that of rice is the highest followed by wheat (Table  2 ). In contrast, the production of other grains such as sorghum, pearl millet, finger millet, little millet and coarse cereals have either remained steady or have declined.

Rice is consumed by the rich and poor as well as rural and urban households. The per capita net availability of food grains increased after the Green Revolution, and rice is a part of the balanced diet along with vegetables, pulses, eggs, meat and fruits. The per capita net availability of rice increased to 69.3 kg/year in 2017 from 58.0 kg/year in 1951 [ 15 , 16 ]. Although rice is widely consumed, with years, the expenditure on cereals decreased from 26.3% in 1987–1988 to 12.0% in 2011–2012 and from 15% in 1987–1988 to 7.3% in 2011–2012 in rural and urban households, respectively. This overall dip in the expenditure may be due to the fact that more money is spent on non-food items in both rural and urban households [ 16 ].

Rice varieties

Among the 40,000 varieties of rice cultivated worldwide, only two major species are cultivated widely— Oryza sativa or the Asian rice and Oryza glaberrima or the African rice. The cultivation of Oryza sativa is practised worldwide; however, the cultivation of the Oryza glaberrima is confined to Africa [ 17 ].

Oryza sativa has two major subspecies: the Indica , long-grain rice and the Japonica , round-grain rice. Japonica rice is mainly cultivated and consumed in Australia, China, Taiwan, Korea, the European Union, Japan, Russia, Turkey and the USA. Indica rice varieties are grown widely in Asia [ 17 ]. These varieties also comprise of the fragrant ones which are priced as premium. The principal fragrant varieties are Hom Mali from Thailand and the various types of Basmati exclusively grown on the Himalayan foothills of India (in the states of Haryana and Punjab) and Pakistan (in the state of Punjab) [ 18 ].

The Indian rice varieties cultivated widely are Basmati , Joha , Jyothi , Navara , Ponni , Pusa , Sona Masuri , Jaya , Kalajiri (aromatic), Boli , Palakkad Matta , etc. The coloured variety includes Himalayan red rice; Matta rice, Kattamodon , Kairali , Jyothy , Bhadra , Asha , Rakthashali of Kerala; Red Kavuni , Kaivara Samba , Mappillai Samba , Kuruvi Kar , Poongar of Tamil Nadu, etc.

The shelf life of rice

In general, it is recommended to store rice in the form of paddy rather than as milled rice, since the husk provides protection against insects and helps prevent quality deterioration. Rice can be stored for long periods only if the following three conditions are met and maintained: (1) the moisture levels of grains, 14% or less and that of seeds must be 12% or less; (2) grains must be well protected from insects, birds and rodents; and (3) grains must be protected from rains or imbibing moisture from the atmosphere. In addition to its nutritive and medicinal properties, red rice and black rice possess several other special features and the most common one is their resistance to insects and pests during storage than brown rice. From the cultivation point of view, red rice possesses resistance to drought, flood, submergence, alkalinity, salinity, and resistance to pests and diseases [ 19 ].

Structure of rice grain

The paddy (also, rough rice or rice grain) consists of the hull, an outer protective covering, and the fruit or rice caryopsis (brown or dehusked rice) [ 20 ]. Rice primarily consists of carbohydrates, proteins and small quantities of fat, ash, fibre and moisture. Vitamins and minerals are largely confined to the bran and germ [ 21 ].

The polished white rice, usually consumed, is the highly refined version of raw rice. The processing and milling of raw rice take away significant parts of the grain, namely the bran and the germ. Both bran and germ are rich in dietary fibre as well as nutrients that are beneficial for human health. Further, if white rice undergoes additional polishing, its aleurone layer getsremoved leading to loss of more nutrients, as this layer is rich in vitamin B, proteins, minerals and essential fats.

In this aspect, the coloured rice finds an advantage as a healthier alternative to white rice. Coloured rice varieties and brown rice varieties have the same harvesting process apart from possessing similar nutritional profiles. These varieties are usually either dehulled or partially hulled with the bran and germ intact. Brown rice is found worldwide, while red rice is confined to the Himalayas, Southern Tibet, and Bhutan, as well as parts of North East and South India. After the removal of husk, brown rice still consists of few outer layers—the pericarp, seed-coat and nucellus; the germ or embryo; and the endosperm. The endosperm consists of the aleurone layer, the sub-aleurone layer and the starchy or inner endosperm (Fig.  1 ). The aleurone layer encloses the embryo. Pigments are confined to the pericarp layer [ 20 ].

Structure of rice grain (Copyright: FAO) [ 22 ]. Paddy consists of the husk, bran, aleurone layer, starchy endosperm and embryo. Brown rice is semi-polished, so it retains embryo while white rice is more polished than brown rice, lacking bran, aleurone and embryo. The removal of bran, aleurone and embryo provides aesthetic appeal to rice and improves shelf life; however, it also removes nutrients and minerals found in the grain

The hull (also, husk) constitutes about 20% of the rough rice weight, but values range from 16 to 28%. The aleurone layer varies from one to five cell layers; it is thicker at the dorsal than at the ventral side and thicker in short-grain than in long-grain rice [ 23 ]. The aleurone and embryo cells are rich in protein and lipid bodies [ 24 ].

The different layers of rice contain different quantities of nutrients. The bran layer is rich in dietary fibre, minerals and vitamin B complex while the aleurone layer contains the least. The endosperm of rice is rich in carbohydrate and also contains a reasonable amount of digestible protein, with favourable amino acid profile than other grains [ 25 ].

Rice processing

Processing of rice mainly involves milling of rice which converts paddy into rice by removing the hull and all or part of the bran layer. Milling of rice is a crucial stage and the objective of milling is to remove the husk and bran so as to produce an edible white rice kernel that is free from impurities.

Rabbani and Ali [ 26 ] report that as a result of processing, some essential nutrients like thiamine and vitamin B are lost. The milling process followed by polishing destroys 67% of the vitamin B 3 , 80% of vitamin B 1 , 90% of vitamin B 6 , 50% of manganese and phosphorus, 60% of the iron, and all of the dietary fibre, as well as the essential fatty acids present in the raw unmilled variety.

The rough rice (also, paddy) on milling produces brown rice, milled rice, germ, bran, broken and husk. Each of these has unique properties and can be used in numerous ways. The extent of value addition in rice and rice products depends upon the utilisation pattern of these components directly or as derivatives. For coloured rice varieties, only the first three steps of milling, namely, pre-cleaning, dehusking and separation, are applied and bran and germ are left intact.

Nutritional information

Raw, long-grain white rice is a good source of carbohydrates, calcium, iron, thiamine, pantothenic acid, folate and vitamin E when compared with maize, wheat and potatoes. It does not contain vitamin C, vitamin A, beta-carotene, lutein and zeaxanthin. It is also notably low in dietary fibre.

• Coloured rice

Brown rice retains its bran layer (containing vitamins, minerals and fibre), as this has not been polished more to produce white rice. The coloured rice varieties are either semi-polished or unpolished (Fig.  2 ). Red-coloured rice varieties are known to be rich in iron and zinc, while black rice varieties are especially high in protein, fat and crude fibre. Red and black rice get their colour from anthocyanin pigments, which are known to have free radical scavenging and antioxidant capacities, as well as other health benefits.

Some traditional South Indian rice varieties. a Red Kavuni . b Kaivara Samba . c Kuruvi Kar . d Poongar . e Kattu Yanam . f Koliyal . g Maappillai Samba. h Black Kavuni . Kavuni possesses anti-microbial activity. Kaivara Samba lowers blood sugar levels. Kuruvi Kar is resistant to drought and consumed by the locals for its health benefits. Poongar is consumed by women after puberty and is believed to avert ailments associated with the reproductive system. Kattu Yanam lowers glucose level in blood and also imparts strength. Koliyal is widely consumed as puttu , a specialty dish. Maapillai Samba has a hypocholesterolemic effect and anti-cancer activity and also improves fertility in men. Black Kavuni is resistant to drought and is popular among locals for its health benefits

Brown rice is highly nutritious. It has low calorie and has a high amount of fibre. Furthermore, it is a good source of magnesium, phosphorus, selenium, thiamine, niacin, vitamin B 6 and an excellent source of manganese. Brown rice and rough rice are rich in vitamins and minerals; this is due to the fact that the vitamins are confined to the bran and husk of the paddy. Rice bran and husk contain a higher amount of calcium, zinc and iron (Table  3 ).

Rice is rich in glutamic and aspartic acids but has a lower amount of lysine. The antinutritional factors that are concentrated mainly in the bran are phytate, trypsin inhibitors, oryzacystatin and haemagglutinin-lectin [ 25 ].

The moisture content plays a significant role in determining the shelf life of foods [ 29 ]. Xheng and Lan [ 30 ] report that moisture influences the milling characteristics and the taste of cooked rice. The differences in genetic makeup and the climatic conditions in which they are cultivated determine the moisture content in rice varieties. As seen from Table  4 , the moisture content of the red rice varieties is variable from 9.3 to 12.94%, the moisture content of brown rice and milled rice is lower than other rice varieties.

Protein is the second major component next to starch; it influences the eating quality and the nutritional quality of rice. In India, the dietary supply of rice per person per day is 207.9 g, this provides about 24.1% of the required dietary protein [ 2 ]. Rice has a well-balanced amino acid profile due to the presence of lysine, in superior content to wheat, corn, millet and sorghum and thus makes the rice protein superior to other cereal grains [ 36 ]. The lysine content of rice protein is between 3.5 and 4.0%, making it the highest among cereal proteins. The endosperm protein comprises of 15% albumin (water soluble), globulin (salt soluble), 5–8% prolamin (alcohol soluble), and the rest glutelin (alkali soluble) [ 27 ].

The coloured rice has high protein content than polished white rice due to the presence of bran. The Srilankan and Chinese varieties have higher protein content than the Indian varieties (Table  4 ). Rice bran proteins are rich in albumin than endosperm proteins. The aleurone protein bodies contain 66% albumin, 7% globulin and 27% prolamin and glutelin [ 37 ].

The fat present in rice is a good source of linoleic acid and other essential fatty acids. The rice does not contain cholesterol [ 36 ]. The lipids or fats in rice are mainly confined to the rice bran (20%, dry basis). It is present as lipid bodies in the aleurone layer and bran. The core of the lipid bodies is rich in lipids and the major fatty acids are linoleic, oleic and palmitic acids [ 38 , 39 ]. Starch lipids present in rice is composed of monoacyl lipids (fatty acids and lysophosphatides) complexed with amylose [ 40 ]. The amount of fat present in various fractions of rice and red rice indicate that red rice varieties from Sri Lanka and India have about 1% fat, while the China red rice has almost doubled this value (Table  4 ).

The presence of fibre in the diet increases the bulk of faeces, which has a laxative effect in the gut. The fibre content is 0.5–1.0% for well-milled rice [ 41 ]. Arabinoxylans, along with β-d-glucan, are the major component of soluble dietary fibre in rice. In addition, rhamnose, xylose, mannose, galactose and glucose are also present in soluble dietary fibre. Insoluble dietary fibre is made up of cellulose, hemicellulose, insoluble β-glucan and arabinoxylans. However, the quantity and amount of non-starch polysaccharide depend upon the rice cultivar, the degree of milling and water solubility [ 42 ]. Among the red rice varieties, Chak-hao amubi (Manipur black rice) has a significantly lower content of crude fibre (Table  4 ).

The variation in ash content of different cultivars of rice may be due to genetic factors or the mineral content of the soil [ 43 ]. The zinc and iron content of red rice is two to three times higher than that of white rice [ 44 ]. The most common minerals found in rice include calcium, magnesium, iron and zinc (Table  3 ).

The proximate composition of rice and its fractions are influenced by the kind of rice and degree of milling, as milling completely or partially removes the bran layer, aleurone layer and embryo. Thus, variation occurs in the nutrition content between the rice fractions of the same rice variety. The variations can be found in the amount of fats, fibre and minerals present in the grain.

Phytochemical composition

The non-nutritive plant chemicals that have a protective or disease-preventing property are known as phytochemicals. The phytochemical compounds are mainly accumulated in the pericarp and bran of the rice kernel. They prevent oxidative damage in foods and also have a wide spectrum of beneficial biological activities.

Phytochemicals present in rice can be divided into the following sub-groups namely carotenoids, phenolics, alkaloids, nitrogen and organo-sulphur containing compounds. Phenolic compounds are further sub-grouped as phenolic acids, flavonoids, coumarins and tannins. Anthocyanins, the major pigment responsible for the colour of red and black rice, are a kind of flavonoids. Maapillai Samba , a kind of red rice from Tamil Nadu, has the highest amount of total polyphenolic compounds and anthocyanin content than the varieties from Sri Lanka, China red rice and Manipur black rice (Table  5 ).

The pigmented cereal grains, such as red and purple/black rice, have phytochemical compounds in higher amounts than non-pigmented varieties. The phytochemicals such as cell wall-bound phenolics and flavonoids are gaining more interest as these compounds can be broken down by digestive enzymes and gut microflora, and as a result, they can be easily absorbed into the body [ 45 ].

The coloured rice bran contains anthocyanins that possess inhibition of reductase enzyme and anti-diabetic activities [ 46 ]. The reductase inhibitors possess anti-androgen effects and are used in the treatment of benign prostatic hyperplasia and to lower urinary tract symptoms. β-sitosterol present in Maappillai Samba (Fig.  2 g) has a hypocholesterolemic effect, improves fertility and also heals colon cancer. Furthermore, stigmasterol found in this variety is a precursor in the production of semi-synthetic progesterone [ 11 ].

Garudan Samba contains 9,12-octadecadienoic acid ( Z , Z ) which has the potential to act as hypocholesterolemic, anti-arthritic, hepatoprotective, 5-alpha-reductase inhibitor, anti-histaminic, anti-coronary and anti-androgenic effects. In addition to these compounds, it also contains several other bioactive compounds [ 47 ].

3-Cyclohexene-1-methanol and α, α,4-trimethyl- present in red Kavuni (Fig.  2 a) possess the anti-microbial activity, and also, 3-hydroxy-4 methoxy benzoic acid is used as a precursor for the synthesis of morphine. In addition to these compounds, fatty acid esters and fatty acids such as dodecanoic acid, ethyl ester (lauric acid ester) and octadecanoic acid are present. Among these bioactive compounds, octadecanoic acid and ethyl esters increase low-density lipoprotein (LDL) cholesterol in the human body [ 48 ].

Health benefits

Depending upon the flavours, culinary needs, availability and its potential health benefits, people choose different varieties of rice. Rice has the ability to provide fast and instant energy. Brown rice and red rice are great sources of fibre, B vitamins, calcium , zinc and iron, manganese, selenium, magnesium and other nutrients. The red and black rice variety gets its rich colour from a group of phytochemicals called anthocyanins, which are also found in deep purple or reddish fruits and vegetables.

Diabetes mellitus

Unlike white polished rice, brown rice releases sugars slowly thus helping to stabilise blood sugar in a sustained manner. This trait makes it a better option for people who are suffering from diabetes mellitus. Further, studies in Asia have shown a relationship between the consumption of white rice and risk of type 2 diabetes. Dietary fibres reduce the absorption of carbohydrates by providing an enclosure to the food, hindering the action of hydrolytic enzymes in the small intestine on food, and increasing the viscosity of food in the intestine [ 49 ]. This plays a vital role in reducing the GI of food thereby preventing the risk of diabetes type 2 [ 50 ]. Proanthocyanidins present in red rice provide protection against type 2 diabetes [ 51 ]. Similarly, anthocyanins present in black rice is said to have a hypoglycemic effect [ 52 ].

Brown rice is rich in manganese and selenium, which play a vital role against free radicals, which acts as a major cancer-causing agent. Due to the presence of these elements and high dietary fibre, brown rice is associated with a lowered risk of cancer. Studies have also correlated the use of whole grains like brown rice with lowered levels of colon cancer. This may be related to its high fibre content, as fibre gets attached to carcinogenic substances and toxins helps to eliminate them from the body, and also keep them away from attaching to the cells in the colon. Proanthocyanins, present in red rice, modulate the inflammatory response and protect against some cancers [ 51 ]. Similarly, anthocyanins which are found abundantly in black rice have anti-carcinogenic properties based on epidemiological and in vivo animal and human-based studies [ 53 ].

Cardiovascular disease

Brown rice may help in lowering the risk of metabolic syndrome, while metabolic syndrome itself is a strong predictor of cardiovascular disease. Red rice contains magnesium that prevents the risk of heart attacks [ 54 ]. Various high-fat diet-induced risk factors for cardiovascular disease were ameliorated by anthocyanin-rich extracts from black rice in rat models [ 55 ].

Cholesterol

Brown rice contains naturally occurring bran oil, which helps in reducing LDL forms of cholesterol. Intake of black rice has found to eliminate reactive oxygen species (ROS) such as lipid peroxide and superoxide anion radicals and lower cholesterol levels due to the presence of compounds such as anthocyanins, polyphenolic compounds, flavonoids, phytic acid, vitamin E and γ-oryzanol [ 56 , 57 ]. Modulation of inflammatory responses by proanthocyanidins in red rice provided protection from cardiovascular disease [ 51 ]. Based on these studies, it is evident that whole grains can lower the chances of arterial plaque buildup, thus reducing the chances of developing heart disease.

Hypertension

Both brown and red rice have high magnesium content than white rice. Magnesium is an important mineral that plays a vital role in the regulation of blood pressure and sodium balance in the body [ 54 ].

Rice varieties such as brown, red and black rice are rich in fibre and have the ability to keep healthy bowel function and metabolic function. Anthocyanins present in red rice have properties that can help in weight management [ 54 ].

Rice protein is hypoallergenic; products from other plant sources such as soy and peanut and animal sources like eggs and milk are a good source of proteins, yet they may cause allergy when consumed. Rice protein provides a solution to this problem because it is hypoallergenic. Furthermore, the anthocyanins present in red rice also have the property to reduce allergy [ 54 ].

Medicinal uses of coloured rice

Among several types of rice, few varieties are used to treat ailments. Every variety of rice is unique in its properties, so the treatment of diseases using rice is not limited to a single variety alone. Many different varieties of rice are employed in treating ailments because of their different properties and characteristics. According to practitioners of Ayurveda, rice creates balance to the humours of the body. Rice enriches elements of the body; strengthens, revitalises and energises the body by removing toxic metabolites; regulates blood pressure; and prevents skin diseases and premature ageing. Rakthasali (a kind of red rice) is efficient in subduing disturbed humours of the body and good for fevers and ulcers; improves eyesight, health, voice and skin health; and increases fertility [ 58 , 59 , 60 , 61 ]. In Ayurveda, Sali , Sashtika and Nivara rice are used to treat bleeding from haemorrhoids (piles); Sali rice is used to treat burns and fractures; Nivara rice is used to treat cervical spondylitis, paralysis, rheumatoid arthritis, neuromuscular disorders, psoriasis, skin lesions, reduce backache, stomach ulcers and snakebite; and Nivara rice is also used in the preparation of weaning food for underweight babies [ 58 , 62 ].

Rice water prepared by soaking rice in water or boiling rice in excess water is used to control diseases. In Ayurvedic preparations, rice varieties such as Mahagandhak ras , Kamdudha ras , Sutsekhar ras , Amritanav ras , Swarnmalti ras , Pradraripu ras , Laghumai ras , Dughdavati , Pradaknasak churna , Pushpnag churna , Sangrahat bhasm and Mukta sukti are used to control ailments such as vaginal and seminal discharges, diarrhoea, constipation and dysentery [ 58 ]. Red rice varieties are known to be used in the treatment of ailments such as diarrhoea, vomiting, fever, haemorrhage, chest pain, wounds and burns [ 63 ]. Matali and Lal Dhan are used for curing blood pressure and fever in Himachal Pradesh. Another red rice variety called Kafalya from the hills of Himachal Pradesh and Uttar Pradesh is used in treating leucorrhoea and complications from abortion [ 64 ]. Kari Kagga and Atikaya from Karnataka are used for coolness and also as a tonic, whereas Neelam Samba of Tamil Nadu is used for lactating mothers [ 65 ]. Kuruvi Kar is resistant to drought and consumed by the locals for its health benefits [ 66 ]. Raktasali is efficient in subduing deranged humours [ 60 , 61 ]. It was also regarded as a good treatment for ailments such as fevers and ulcers. It is also believed that it improves eyesight and voice; acts as diuretic, spermatophytic, cosmetic and tonic; and was also antitoxic [ 59 ].

Traditional food and its importance

Ayurvedic treatises mention red rice as a nutritive food and medicine, so the red rice is eaten as a whole grain. Red rice varieties such as Bhama , Danigora , Karhani , Kalmdani , Ramdi , Muru , Hindmauri and Punaigora of Jharkhand and Chattisgarh are rich in nutrition and provide energy and satiety for a whole day [ 67 , 68 ]. Traditionally, various foods such as pongal , puttu , adai , appam , idli , dosai , idiyappam , adirasam , kozhukattai , modakam , payasam , semiya , uppuma , flaked rice, puffed rice, etc. are prepared and consumed. In Tamil Nadu and Kerala, paddy is parboiled prior to milling. This hydrothermal process facilitates the migration of nutrients such as vitamins and minerals from the bran and the aleurone layer to the endosperm [ 69 ]. Rice takes the place of major cereal consumed in the South Indian diet while it is wheat that holds the position in North Indian diet. Dosai , idli , pongal , appam , semiya , uppuma , kichadi and idiyappam are prepared and consumed for breakfast along with wide varieties of chutney. The specialty dish called puttu made from rice is also prepared and consumed for breakfast. The lunch of South India is a combination of cooked parboiled rice, poriyal , eggs, meat, sambar , dal curry, rasam , pappad , moore (buttermilk) or curd and/or dessert, payasam . The dinner usually consists of idli , dosai , idiappam , cooked rice and curries. Various other dishes are also prepared from rice and include biryani, pulao, fried rice, curd rice, tamarind rice, sambar rice, jeera rice, lemon rice, coconut rice, etc. In Tamil Nadu, appams and idlis are also made using the red rice. Koliyal and Garudan Samba ( Kaadai Kazhuththaan ) of Tamil Nadu are used in the preparation of a specialty dish called puttu [ 47 ]. Flatbread and chapatti are made from red Gunja and glutinous rice is used in making puttu , a South Indian meal [ 70 ]. Several products such as cookies, murruku (a type of South Indian snack), are also made using the various coloured rice varieties.

Rice also plays a major role in festivals celebrated in India. The harvest festivals are celebrated with several delicacies made from freshly harvested paddy. In Tamil Nadu, sarkarai pongal is made from raw rice, green gram, milk and jaggery; in Assam, fried rice balls named ghila pitha are prepared and consumed; in West Bengal, traditional Bengali delicacies are made from freshly harvested rice and jaggery, the most famous one is home-made sweets from rice pitha and karpursal or banapuli , and Basmati rice is also used to make Bengali paish .

Parboiled red rice widely consumed in Kerala includes Thondi , Matta , Paal Thondi , Kuruva , Chitteni and Chettadi . Seeraga Samba is an aromatic rice variety consumed widely in Tamil Nadu and Kerala; it is known as ‘Basmati of South India’ and used in the preparation of biryani. Similarly, Jatu of Kulu valley, Ambemohar of Maharastra, Dubraj of Madhya Pradesh, Joha of Assam, Kamod of Gujarat, Badshah bhog of West Bengal and Odisha, Radhunipagla of West Bengal, Katrini and Kalanamak of Uttar Pradesh and Bihar, Gandha samba of Kerala, Kalajira of Odisha and Chakhao varieties of Manipur are prized for its aroma [ 64 , 67 ].

Today, the spotlight is on the increased production of these traditional varieties, promoting the consumption among the younger generation and production of nutritious and novel value-added products from coloured rice.

Although India is home to traditional red rice varieties and their use has been common among the practitioners of traditional medicine and communities as part of their cultural heritage, their functional effects and health benefits in terms of modern scientific methodology are far and few. Due to the insufficient availability of data, the beneficial properties of these varieties still remain unknown to a majority of the population. So, to leverage their health benefits, extensive research on these native coloured varieties by the stakeholders needs to be promoted so that they are available to consumers as a part of the daily diet or specialty functional foods.

Availability of data and materials

Not applicable

Agricultural Statistics Division, Third advance estimates of production of food grains for 2016-17, Department of Agriculture, Cooperation and Farmers Welfare, India. https://eands.dacnet.nic.in/Advance_Estimate/3rd_Adv_Estimates2016-17_Eng.pdf . Accessed 20 Nov 2018.

Kennedy G, Burlingame B, Nguyen VN. Nutritional contribution of rice and impact of biotechnology and biodiversity in rice-consuming countries, Food and Agriculture Organization of the United Nations. http://www.fao.org/3/Y4751E/y4751e05.htm . Accessed 26 June 2019.

The Hindu, The Hindu Group (2012), ‘From 1,10,000 varieties of rice to only 6,000 now.’ http://www.thehindu.com/news/national/karnataka/from-110000-varities-of-rice-to-only-6000-now/article3284453.ece . Accessed 5 Jan 2019.

Devi GN, Padmavathi G, Babu VR, Waghray K. Proximate nutritional evaluation of rice ( Oryza sativa L.). J Rice Res. 2015;8(1):23–32.

Google Scholar  

Gnanamanickam SS. Rice and its importance to human life. In: Biological Control of Rice Diseases. Progress in Biological Control 2009;(8):1-11.

Possehl GL. The Indus Civilization: a contemporary perspective. AltaMira Press. CA; Oxford: Walnut Creek; 2002.

Fuller DQ, Qin L, Harvey E. Evidence for a late onset of agriculture in the lower Yangtze region and challenges for an archaeobotany rice. In: Sanchez-Mazas A, Blench R, Ross MD, Peiros I, Lin M, editors. Past Human Migrations in East Asia, Matching Archaeology, Linguistics and Genetics. London: Routledge; 2007. p. 40–83.

Tewari R, Srivastava RK, Saraswat KS, Singh IB, Singh KK. Early farming at Lahuradewa. Pragdhara. 2008;18:347–73.

Yosida S. Climatic environment and its influence. In: Fundamentals of rice crop science. Manila: International Rice Research Institute; 1981. p. 65.

Ahuja SC, Ahuja U. Rice in religion and tradition. 2 nd International Rice Congress. 2006. https://www.researchgate.net/publication/321334487 . Accessed 23 May 2019.

Sulochana S, Singaravadivel K. A study on phytochemical evaluation of traditional rice variety of Tamil Nadu -'Maappillai Samba' by GC-MS. International Journal of Pharma and Biosciences. 2015;6(3):606–11.

Gomez KA. Rice, the Grain of culture. Siam Society Lecture Series, The Siam Society, Thailand. 2001. https://www.thairice.org/html/article/pdf_files/Rice_thegrain_of_Culture.pdf . Accessed 10 June 2018.

Ricepedia, CGIAR, IRRI, Philippines. Rice as a Crop. www.ricepedia.org/rice-as-a-crop . Accessed 10 Jan 2018.

Food and Agricultural Organisation of the United Nations. Rice Market Monitor FAO. 2017. http://www.fao.org/3/I8317EN/I8317EN.pdf . Accessed 20 Oct 2018.

Department of Agriculture, Cooperation and Farmers Welfare. Ministry of Agriculture, India. 2017. http://agricoop.nic.in/sites/default/files/pocketbook_0.pdf . Accessed 2 Mar 2019.

Directorate of Economics and Statistics (DES), Ministry of Agriculture, India. 2014. https://eands.dacnet.nic.in/PDF/Glance-2016.pdf . Accessed 20 Nov 2018.

Ricepedia, CGIAR, IRRI, Philippines. Cultivated rice species. http://ricepedia.org/rice-as-a-plant/rice-species/cultivated-rice-species . Accessed 10 Jan 2018.

Calpe C. Rice International Commodity Profile. Food and Agricultural Organisation of the United States. 2006. http://www.fao.org/fileadmin/templates/est/COMM_MARKETS_MONITORING/Rice/Documents/Rice_Profile_Dec-06.pdf . Accessed 25 Sept 2018.

Kitano H, Tamura Y, Satoh H, Nagato Y. Hierarchial regulation of organ differentiation during embryogenesis in rice. Plant J. 1993;3:607–10.

Juliano BO, Bechtel DB 1985. The rice grain and its gross composition. In: Juliano BO, editor. Rice Chemistry and Technology, American Association of Cereal Chemists: Eagan, MN, USA. 1985. p. 17-57.

Tangpinijkul N. Rice Milling System: paper prepared for a training course on Grain Post-harvest Technology Manhattan Klongluang Hotel, Pathumthani, Thailand. 2010. https://pdfs.semanticscholar.org/ce4e/874284982e5b7603b0373a554c786c763c8e.pdf . Accessed 25 June 2019.

Kennedy G, Burlingame B, Nguyen N. Nutrient impact assessment of rice in major rice-consuming countries. Food and Agriculture Organisation of the United Nations. http://www.fao.org/3/Y6159T/y6159t04.htm#Note1 . Accessed on 17 July 2019.

Del Rosario AR, Briones VP, Vidal AJ, Juliano BO. Composition and endosperm structure of developing and mature rice kernel. Cereal Chem. 1968;45:225–35.

Tanaka K, Ogawa M, Kasai Z. The Rice Scutellum. II. A comparison of scutellar and aleurone electrodense particles by transmission electron microscopy including energy-dispersive X-ray analysis. Cereal Chem. 1977;54:684–9.

Juliano BO. Rice in human nutrition. FAO Food and Nutrition Series No. 21, Rome, Italy. 1993. 162.

Rabbani GH, Ali M. New ideas and concepts, rice bran: a nutrient dense mill-waste for human nutrition. The ORION Med. J. 2009;32(3):458–62.

Juliano BO. Rice: Chemistry and Technology. 2nd ed. St. Paul, MN: Am. Assoc. Cereal Chem; 1985b. p. 774.

Pedersen B, Eggum BO. The influence of milling on the nutritive value of flour from cereal grains. Plant foods Human Nutrition. 1983;33:267–78.

Ebuehi OAT, Oyewole AC. Effect of cooking and soaking on physical characteristics, nutrient composition and sensory evaluation of indigenous and foreign rice varieties in Nigeria. African Journal of Biotechnology. 2007;6(8):1016–20.

Xheng X, Lan Y. Effects of drying temperature and moisture content on rice taste quality. Agricultural Engineering International: The CIGRE Journal 2007:9. Manuscript FP07 023.

Eggum BO, Juliano BO, Maniñgat CC. Protein and energy utilization of rice milling fractions by rats. Qual. Plant. Plant Foods Hum. Nutr. 1982;31:371–6.

Umadevi M, Pushpa R, Sampathkumar KP, Bhowmik D. Rice- Traditional medicinal plant in India. Journal of Pharmacognosy and Phytochemistry. 2012;1(1):6–12.

Longvah T, Ananthan R, Bhaskarachary K, Venkaiah K. Proximate principles and dietary fibre. Hyderabad, India: Indian Food Composition Tables, National Institute of Nutrition, Department of Health Research, Ministry of Health and Family Welfare, Government of India; 2017. p. 3.

Sompong R, Siebenhandl-Ehn S, Linsberger-Martin G, Berghofer E. Physicochemical and antioxidative properties of red and black rice varieties from Thailand, China and Sri Lanka. Food Chemistry. 2011;124:132–40.

Saikia S, Dutta H, Saikia D, Mahanta CL. Quality Characterisation and estimation of phytochemicals content and antioxidant capacity of aromatic pigmented and non-pigmented rice varieties. Food Research International. 2012;46(1):334–40.

Eggum BO. The nutritional value of rice in comparison with other cereals. In: Proceedings, Workshop on Chemical Aspects of Rice Grain Quality, IRRI. Los Banos, Laguna, The Philippines; 1979. p. 91–111.

Tanaka N, Fujita N, Nishi A, Satoh H, Hosaka Y, Ugaki M. The structure of starch can be manipulated by changing the expression levels of starch branching enzyme IIb in rice endosperm. Plant Biotechnol. J. 2004;2:207–516.

Juliano BO, Goddard MS. Cause of varietal difference in insulin and glucose responses to ingested rice. Qual. Plant. Plant Foods Hum. Nutr. 1986;36:35–41.

Tanaka Y, Resurreccion AP, Juliano BO, Bechtel DB. Properties of whole and undigested fraction of protein bodies of milled rice. Agric. Biol. Chem. 1978;42:2015–23.

Choudhury NH, Juliano BO. Effect of amylose content on the lipids of mature rice grain. Phytochemistry. 1980;19:1385–9.

Oko AO, Onyekwere SC. Studies on the proximate chemical composition and mineral element contents of five new lowland rice varieties in Ebonyi State. Int J Biotechnology Biochemistry. 2010;6(6):949–55.

Lai VMF, Lu S, He WH, Chen HH. Non-starch polysaccharide compositions of rice grains with respect to rice variety and degree of milling. Food Chemistry. 2007;101(3):1205–10.

AO O, BE U, AA E, N D. Comparative analysis of the chemical nutrient composition of selected local and newly introduced rice varieties grown in Ebonyi State of Nigeria. Int J Agriculture Forestry. 2012;2(2):16–23.

Ramaiah K, Rao MVBN. Rice breeding and genetics ICAR science monograph 19. New Delhi, India: Indian Council of Agricultural Research; 1953.

Chen C-H, Yang J-C, Uang Y-S, Lin C-J. Improved dissolution rate and oral bioavailability of lovastatin in red yeast rice products. Int J Pharm. 2013;444(1-2):18–24.

Yawadio R, Tanimori S, Morita N. Identification of phenolic compounds isolated from pigmented rices and their aldose reductase inhibitory activities. Food Chemistry. 2007;101(4):1616–25.

Sulochana S, Meyyappan RM, Singaravadivel K. Phytochemical screening and GC-MS analysis of Garudan Samba traditional rice variety. Int J Environ Agri Res. 2016;2(4):44–7.

Sulochana S, Meyyappan RM, Singaravadivel K. Mass spectrometry analysis of indian traditional variety “Red Kavuni” in comparison with high yielding popular variety of Tamil Nadu ADT 43 under raw and hydrothermally processed condition. Indo Am J Pharm Res. 2016;6(5):5358–63.

Jenkins DJA, Leeds AR, Gassell MA, Cocket B, Alberti KGM. Decrease in post-prandial insulin and glucose concentrations by gaur and pectin. Ann Intern Med. 1977;86:20–3.

Babu DP, Bhakyaraj R, Vildhyalakshmi R. A low cost nutritious food “tempeh”- a review. World J. Dairy Food Sci. 2009;4(1):222–7.

Chen M-H, McClung AM, Bergman CJ. Concentrations of ligomers and polymers of proanthocyanidins in red and purple rice bran and their relationships to total phenolics, flavonoids, antioxidant capacity and whole grain color. Food Chemistry. 2016;208:279–87.

Tsuda T, Horio F, Uchids K, Aoki H, Osawa T. Dietary cyanidin 3-O-beta-D-glucoside-rice purple corn color prevents obesity and ameliorates hyperglycemia in mice. J. Nutr. 2003;133(7):2125–30.

Pojer E, Mattivi F, Johnson D, Stockley CS. The case for anthocyanin consumption to promote human health: a review. Compr. Rev. Food Sci, Food Saf. 2013;12(5):483–508.

Institute of Medicine (US). Standing Committee on the Scientific Evaluation of Dietary References Intakes. Dietary reference intakes for calcium, phosphorous, magnesium, vitamin D, and fluoride. Magnesium. Washington, DC: National Academies Press; 1997.

Shao Y, Xu F, Sun X, Bao J, Beta T. Identification and quantification of phenolic acids and anthocyanins as antioxidants in bran, embryo and endosperm of white, red and black rice kernels ( Oryza sativa L.). J Cereal Sci. 2014;59:211–8.

Ichikawa H, Ichiyanagi T, Xu B, Yoshii Y, Nakajima M, Konishi T. Antioxidant activity of anthocyanin extract from purple black rice. J. Med. Food. 2001;4(4):211–8.

Nam YJ, Nam SH, Kang MY. Cholesterol - lowering efficacy of unrefined bran oil from the pigmented black rice ( Oryza sativa L cv. Suwon 415) in hypercholesterolemic rats. Food Sci. Biotechnol. 2008;17:457–63.

Ahuja U, Ahuja SC, Thakrar R, Singh RK. Rice- a nutraceutical. Asian Agri-History. 2008;12(2):93–108.

Bhat FM, Riar CS. Health benefits of traditional rice varieties of temperate regions. Med. Aromat. Plants. 2015;4:198. https://doi.org/10.4172/2167-0412.1000198 .

Krishnamurthy KS. The Wealth of Susruta. Tamil Nadu, India: International Institute of Ayurveda, Coimbatore; 1991.

Kumar TT. History of rice in India. Delhi, India: Gian Publishers; 1988.

Sharma PV. Classical uses of medicinal plants. Chaukhamba Vishwabharati, Varanasi. Uttar Pradesh, India. 1996:848.

Hedge S, Yenagi NB, Kasturiba B. Indigenous knowledge of the traditional and qualified Ayurveda practitioners on the nutritional significance and use of red rice in medications. Indian journal of traditional knowledge. 2013;12:506–11.

Ahuja U, Ahuja SC, Chaudhary N, Thakrar R. Red rices-past, present, and future. Asian Agri-History. 2007;11(4):291–304.

Arumugasamy S, Jayashankar N, Subramanian K, Sridhar S, Vijayalakshmi K. Indigenous rice varieties. Centre for Indian Knowledge System (CIKS), Chennai: Tamil Nadu India; 2001.

The Hindu. The Hindu Group. India: India. Indigenous rice varieties make a comeback The Hindu Group; 2018. http://www.thehindu.com/life-and-style/food/thanals-save-our-rice-is-reviving-indigenous-rice-varieties/article22420554.ece .

Ahuja U, Ahuja SC, Thakrar R, Shobha Rani N. Scented rices of India. Asian Agri-History. 2008;12(4):267–83.

Rahman S, Sharma MP, Sahai S. Nutritional and medicinal value of some indigenous rice varieties. Indian J Traditional Knowledge. 2006;5(4):454–8.

Bhattacharya KR. Parboiling of rice. In: Champagne NET, editor. Rice chemistry and technology. American Association of Cereal Chemists Inc. St. Paul, Minnesota; 2004. p. 329–404.

Rani S, Krishnaiah K. Current status and future prospects of improving traditional aromatic rice. In: Chaudhary RC and Tran DV, editors, Specialty Rices of the World: Breeding, Production, and Marketing, FAO, Rome, Italy and Oxford IBH Publishers, India. 2001. p. 49-79.

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Rathna Priya T. S., Ann Raeboline Lincy Eliazer Nelson, Kavitha Ravichandran & Usha Antony

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RP initiated the idea of the article and authored all sections of the article except sections on medicinal uses of coloured rice, traditional food products and value-added products and new products. ARLEN authored sections on medicinal uses of coloured rice, traditional food products and value-added products and new products; co-authored other sections of the article KR co-authored the sections on the importance of rice in India, rice processing, production and demand of rice varieties, origin and spread of rice and value-added products and new products; and provided critical inputs to revise the manuscript. UA co-authored the sections on structure of grain, nutrition, health benefits and traditional food products; and provided critical inputs to revise the manuscript. All the authors read and approved the final manuscript.

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Rathna Priya, T., Eliazer Nelson, A.R.L., Ravichandran, K. et al. Nutritional and functional properties of coloured rice varieties of South India: a review. J. Ethn. Food 6 , 11 (2019). https://doi.org/10.1186/s42779-019-0017-3

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DOI : https://doi.org/10.1186/s42779-019-0017-3

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Ready to eat shelf-stable brown rice in pouches: effect of moisture content on product’s quality and stability

• Original Paper
• Published: 15 September 2021
• Volume 247 , pages 2677–2685, ( 2021 )

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• Enrico Federici 1 , 2 ,
• Valentina Gentilucci 1 ,
• Valentina Bernini   ORCID: orcid.org/0000-0002-2255-4384 1 ,
• Elena Vittadini   ORCID: orcid.org/0000-0001-9181-0815 3 &
• Nicoletta Pellegrini   ORCID: orcid.org/0000-0002-9178-5274 4  

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Despite several nutritional benefits of brown rice (BR) its consumption remains limited compared to white rice. Two of the major barriers to its consumption are long cooking time and limited shelf life. However, those two hurdles can be overcome through the development of shelf-stable BR pouches to create new ready-to-eat (RTE) products, a food category that is gaining important market shares. Nevertheless, scarce information is available on the production and shelf-life stability of ready-to-eat BR products. The first objective of this study was the determination of the optimal moisture range to fully cook BR. The second objective was to determine the effect of moisture content and storage time on two fundamental parameters for consumer’s acceptance of rice: color and texture. Three RTE BR pouches with moisture contents of 54%, 57% and 60% were produced and texture and color were evaluated after 1 year of storage. Significant changes in hardness and stickiness were reported during long-term storage. Moisture content negatively affected hardness and positively affected stickiness. Furthermore, storage time and moisture showed a significant effect on rice color. The present results provide information that will be useful to design new RTE meals to promote brown rice consumption.

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Introduction

Ready-to-eat (RTE) meals are becoming popular among consumers due to their convenience and the change of eating habits. The busy lifestyles of young professionals and entrepreneurs have accounted for an increase in the demand for labor-saving RTE meals [ 1 ]. Availability of RTE meals has further gained importance in light of the COVID-19 pandemic, as they provide not only an easy solution to the need to minimize handling and contact-free delivery of food but also are a lunch option alternative for individuals who would have normally fed at restaurants that have been largely shut down [ 2 , 3 , 4 ].

Rice is a popular ingredient in RTE food in Europe, America and Asia [ 5 ], and it is commonly consumed and used in RTE as polished (white) rice. White rice is preferred from consumers to brown rice (BR) since the latter has a longer cooking time, chewy texture, and poor appearance [ 6 , 7 , 8 ]. Moreover, products incorporating BR also negatively impact the flavor of a product [ 9 ]. However, BR has positive nutritional features as it is rich in dietary fiber, polyphenols, and lipids which are available in good amounts in the bran layer of caryopsis [ 10 ]. Compared to BR, white rice has a poorer nutritional value as, during milling, removal of bran and germ diminishes fiber, vitamins and minerals as well as protein content [ 11 ]. Thus, the utilization of BR in RTE foods could be a good strategy to increase not only its nutritional value but also take out the burden of long cooking time [ 12 ].

A popular technology to produce RTE cereal products is sterilization in pouches. However, when this intense thermal treatment is performed on white rice grain, its integrity is lost resulting in a sticky product with a soft texture. A potential solution to produce rice-based RTE aseptic products is the utilization of BR. The long cooking time of BR is a positive feature for aseptic processing since it allows to sterilize the product with limited effects on grain structural integrity. Aseptic processing also removes the need for long cooking by the consumer, which is a barrier for BR consumption. Furthermore, the use of BR, instead of white rice, as the main ingredient in these highly processed foods, which are potentially associated with poor dietary quality and obesity [ 13 ], could greatly improve their nutritional value. Fiber, minerals and proteins present in BR are not lost during the cooking-sterilization process in an enclosed pouch, and bioactive compounds present in rice bran are more available after being thermally treated [ 14 ]. Finally, BR rice contains a higher amount of bioactive lipids and flavonoids than white rice [ 15 ] which may further support the human immune system also against COVID-19 [ 16 ]. All these characteristics make BR an optimal candidate for the design of RTE BR-based functional foods. Such RTE products could be a mean to contribute significantly to increase the consumption of BR and to help consumers in familiarizing with the consumption of whole-meal foods [ 6 ].

To the authors’ best knowledge, no information is available in the literature on the optimization of RTE BR cooking process in pouches, and on the characterization of its shelf-life stability. In this study, cooking conditions of BR have been optimized at first, and then, the effect of hydration level and storage time on main quality attributes (e.g. texture and color) of RTE BR have been evaluated.

Materials and methods

Brown rice optimal cooking time determination.

BR of Roma variety has been gently provided by a local producer (Grandi Riso S.p.A., Codigoro, Ferrara, Italy). Rice was cooked in boiling water (1:20, rice:water) in a pot for variable lengths of time (10, 15, 20, 25, 30, 35, 40 and 45 min). BR and cooking water were separated by draining rice with a colander and cooled down to room temperature for 30 min before further analysis. The minimum cooking time to consider BR cooked was calculated through the determination of the point of inflection of the rice moisture absorption curve [ 17 ]. All the experiments were carried out at the Department of Food and Drug, University of Parma (Italy).

Brown rice moisture content

The moisture content of BR at variable cooking times was evaluated by drying in an air forced oven at 105 °C to constant weight according to AACCI method 44-15.02. The analysis was performed in triplicate for each cooking time.

Brown rice texture

Texture profile analysis (TPA) was performed on rice samples using a Texture Analyzer (Stable Micro Systems, Godalming, UK) equipped with a 25 kg load cell and an aluminum cylinder probe with a diameter of 40 mm, following Boluda-Aguilar et al. [ 2 ] with some modification. A test speed of 0.1 mm/sec and a total strain of 75% were used. Three g of rice was spread in single layer grain on the instrument base. Three replicates were performed on each sample. Textural attributes considered were: hardness (N, maximum force of the first compression) and stickiness (N.cm −1 , negative area after the first compression) [ 18 ].

Brown rice grain morphology

Forty BR kernels were arranged in a thin layer on a transparent plastic sheet. A dimensional reference was added to determine pixel:mm ratio of every image. BR pictures were acquired using a scanner (HP Scanjet 8200) with a resolution of 600 pixel and analyzed with the software ImageJ [ 19 ]. Acquired images were then converted in black and white and threshold adjusted before measuring the averaged area, solidity, and circularity of rice kernels.

Brown rice cooking loss

Cooking loss, defined as the amount of solids lost into the cooking water, was determined according to the AACC official method 16–50.

RTE brown rice poches production and microbial safety assessment

RTE BR pouches were produced by a local producer. BR was washed, inserted into a pouch (250 g, composite packaging, 406,735, Goglio Packaging System, Milan, Italy) together with enough tap water to reach theoretical total moisture contents of 54, 57, and 60 g water/100 g product. Pouches were then hermetically sealed, placed vertically into baskets that were then inserted into a horizontal autoclave, which was first filled with water at 85 °C, heated to 118 °C and held for 35 min. The cooking-sterilization process was static, not allowing for pouches rotation. At the end of the thermal treatment, pouches were cooled down, unloaded, and stored at room temperature to reproduce domestic preservation conditions. One pouch was open for every point of shelf life at the following times: 0, 40, 80, 120, 160, 270, and 365 days. For every storage time, microbiological analysis was performed to assess the sterility of the product. Aliquot of samples were homogenized 1:10 (Seward Stomacher, 400 circulator, UK) with sterile Ringer solution (Oxoid, Basingstoke, UK), tenfold diluted and plated in duplicate on different culture media. Total mesophilic and spore-forming mesophilic bacteria were determined on Plate Count Agar (PCA) (Oxoid, Basingstoke, UK) after incubation at 30 °C for 48 h. Yeast and molds were grown on Yeast Extract Dextrose Chloramphenicol Agar (YEDC) (REMEL Lenexa, USA) after incubation at 25 °C for 72–120 h. Brilliance™ Bacillus cereus Agar Base supplemented with Brilliance ™ Bacillus cereus selective supplement (Oxoid, Basingstoke, UK) and incubated at 37 °C for 48 h was used to enumerate Bacillus cereus . Regarding spore-forming bacteria, first dilution of the samples was treated at 85 °C for 15 min before plate counts. Analyses were carried out in duplicate and for each sampling time average values ± standard deviations were reported as UFC/g.

Water spatial distribution in pouches

Brown rice moisture content homogeneity throughout the pouch was assessed by means of its moisture content, by extracting rice samples from 24 different locations in the pouch. Sampling locations were equally distanced to assure homogeneous distribution of sampling points through the pouch. Moisture content was then determined as described in 2.1.1. Moisture spatial distribution was measured in three pouches per each BR moisture content.

Brown rice color in pouches

Color was measured on the surface of cooked BR using a Minolta Colorimeter (CM 2600d, Minolta Co., Osaka Japan) in the 400–700 nm range using illuminant D65 and for a 2° position of the standard observer. L* (lightness), a ∗ (redness), b ∗ (yellowness) were measured for at least ten measurements at each cooking time and each shelf-life time. ΔE was calculated according to Eq.  1 , taking the color of rice cooked at time 0 as reference.

Brown rice texture in pouches

Each BR pouch was massaged to un-grain and mix their content prior to be opened to extract BR samples (80 g). Samples were transferred into a closed container and heated in a microwave for 1 min at 900 W, to replicate a standard heating procedure the product would undergo prior to consumption. Heated rice was allowed to cool down to room temperature prior to texture profile analysis (TPA) that was performed as described in “ Brown rice texture ”.

Statistical analysis

Data are presented as average ± standard deviation. At least three replicates were performed for each analysis. Significant differences ( p  ≤ 0.05) among samples were calculated by multivariate analysis of variance (MANOVA) with a Tukey-high significant difference test. SAS 9.4 (SAS institute corporation, NC, USA) was used to perform the statistical analysis.

Results and discussion

The cooking process of BR in excess water was studied with respect to water uptake and textural changes occurring in rice kernels for different lengths of time. This preliminary study was carried out to determine the amount of water needed to reach optimal cooking of BR, and therefore to design conditions to achieve optimal cooking of BR within sealed pouches. Optimal cooking time has been reported to correspond with the point at which most of the starch present in the kernel is gelatinized, condition that can be determined with the inflection point of a moisture absorption kinetic curve [ 17 ]

Appearance of BR after cooking for different times is shown in Fig.  1 . BR kernels cooked up to 20 min were characterized by a smooth surface and retained their original shape and structural integrity. At 25 min cooking, BR kernels started to break due to moisture absorption and volume expansion indicative of an important amount of gelatinized starch. The number of broken kernels increased with cooking time and their shape become progressively more irregular. After 45 min, an important amount of starch leached out from the kernels, as it was observable by the presence of a large quantity of material collecting on the plastic sheet used to arrange the sample for image acquisition. BR kernels area was measured as a function of cooking time (Table 1 ), and it was found to progressively increase from 20.9 ± 2.7 to 25.3 ± 3.7 mm 2 with cooking time increase from 10 to 25 min. Rice kernels expansion is due, primarily, to water absorption, the consequent swelling, and gelatinization of starch granules during cooking. However, after 25 min of cooking, even though rice kept absorbing water, its area increased at a slower pace, suggesting that rice starch had reached its maximum swelling ability and was not able to further expand [ 20 ]. At longer cooking times, BR kernels underwent breakage and disruption decreased their solidity, circularity and slightly, but nor significantly, increased their overall area (Table 1 ).

Appearance of brown rice kernels after cooking in a pot for different lengths of time

Water uptake in BR during cooking was monitored and it was found, as expected, to increase with increasing cooking time (Fig.  2 ). Moisture content of BR gradually increased from 38.0 ± 0.2 to 52.9 ± 0.8 g water/100 g product up to 25 min cooking. At longer cooking times, water absorption still occurred but at a slower rate, reaching a maximum of 64.9 ± 0.2 g water/100 g product at 45 min cooking. From the data reported in Fig.  2 , it is possible to observe the occurrence of an inflection after 25 min of cooking, leading to the identification of 25 min as the minimum cooking time at which the rice could be considered cooked in excess boiling water [ 17 ]. Solid loss from BR kernels increased exponentially with increasing cooking time, as measured by the increase in turbidity of the cooking water (Fig.  2 ), resulting from solids (primarily amylose and short-chain amylopectin) lost in cooking water [ 21 ]. At the initial stages of cooking, turbidity grew slowly due to the limited starch gelatinization with few broken starch granules and the presence of intact husks that protected and retained the starchy endosperm within the kernel. Increasing cooking times lead to more extensive gelatinization and an increasing number of kernels showing damaged husks, resulting in an increased release of solids.

Changes in physico-chemical attributes of brown rice (moisture content, kernel area, hardness) and cooking water (turbidity) during cooking. Gray area represents the range of acceptable cooking conditions

Textural attributes of BR significantly changed upon cooking due to water absorption and structural changes occurring in rice constituents, primarily associated with starch gelatinization. BR hardness was very high at the beginning of the cooking process, 255.1 ± 11.6 N after 10 min of cooking, and gradually decreased, as expected, to 56.4 ± 6.8 N after 45 min of cooking. Hardness decrease could be divided into two phases reflecting the trend observed for moisture uptake. A first phase, characterized by a rapid decrease in hardness, was observed until 25 min of cooking, and a slower decrease for further cooking from 25 to 45 min.

Studies on the degree of starch gelatinization at variable cooking times in pasta [ 22 ] indicated that only 80% of starch was gelatinized at the cooking time suggested by the pasta producer, while 90% starch gelatinization was reached only in an overcooked product. In this respect, a complete starch gelatinization is not required to consider a product cooked [ 23 ]. Therefore, we can expect starch to be mainly gelatinized in BR at the inflection point where water uptake is reduced, but it can be considered cooked over a larger range of moisture contents.

In this work, the extremes of BR cooking were set, for the lower limit, in correspondence of the inflection point of the moisture uptake curve (25 min, corresponding to a reduction of water uptake), and for the higher limit, at 35 min. The value of 35 min was selected because it corresponded to a condition where kernel damage was still contained. This statement was supported by limited turbidity of the cooking water (593 NTU) and BR kernel high stickiness (8.4 ± 2.1 N cm −1 ) as compared to 1082 NTU and 4.2 ± 0.8 N cm −1 , respectively, at 40 min cooking, indicating a shift of solids from BR kernel surface into the cooking water. The moisture content of rice at the lower (25 min) and higher (35 min) end of the cooking range were 52.9% ± 0.8 and 59.9% ± 1.0, respectively. Based on the results obtained, the moisture contents to cook rice in pouches were designed to be 54, 57 and 60%.

RTE brown rice in pouches: characterization and long-term shelf-life stability

Moisture content and spatial distribution in pouches.

Rice was cooked in pouches with the theoretical amount of water to reach the minimal amount of moisture necessary to cook the rice. Total mesophilic bacteria, spore-forming bacteria, yeasts and molds and B. cereus were not present above the detection limit (10 UFC/g) throughout the shelf life considered, confirming the efficacy of the treatment. At the end of aseptic processing, which was carried out in a static manner, the real moisture content of rice was determined. The average moisture content of BR in the pouches was 53.9% ± 3.8, 57.1% ± 0.7 and 60.3% ± 0.5 and well approximated the theoretical target moisture contents (54%, 57%, and 60% moisture content, respectively). The averaged moisture content of all samples remained constant for the duration of the storage time (1 year).

Water content in different locations of the pouches was measured to verify homogeneity of the cooking process inside pouches to ensure the product’s uniformity. Water distribution was not homogenous in the 54% moisture pouch, while it was evenly distributed throughout the sample in other pouches (57 and 60%), as shown in Fig.  3 . BR in the 54% moisture pouch had a higher moisture content at the top and a lower at the bottom of the pouch (Fig.  3 ). This can be explained by the dynamics of the cooking process in a confined environment (pouch); upon heating, water turns into vapor and moves towards the upper zone of the pouch, creating a dis-uniform distribution of water that is particularly relevant in the lower moisture product. An uneven water distribution causes a different degree of water penetration into rice kernel and, consequently, uneven cooking of the product. Water availability affects starch gelatinization temperature [ 24 ]. Therefore, different moisture levels can also affect starch gelatinization. BR at 54% moisture had limited available water, leaving some rice kernels, located in the lower part of the pouch, underhydrated and not able to gelatinize under the processing conditions. This resulted in uncooked rice kernels with a more vitreous aspect. Therefore, we can conclude that 54% moisture is not enough to homogeneously cook BR in pouches. On the contrary, in the pouches with 57% and 60%, the amount of moisture was enough to cook the rice evenly within the pouch ensuring homogeneous water distribution and rice grain textural attributes. These data showed that the cooking dynamic of BR in a pot and within a pouch is different and that particular care must be taken in defining the optimal moisture content of a product to ensure proper cooking of the entire pouch content and its sterilization.

Moisture content of brown rice as a function of spatial distribution in pouches with different theoretical moisture contents

Texture analysis

Hardness and stickiness of BR after re-heating in a microwave oven are shown in Table 2 . Hardness and stickiness were measured as they are the most important textural attributes that affect consumer acceptability in rice [ 25 ]. As expected, water content was found to be the most important factor affecting BR hardness, with rice kernels becoming softer with increasing moisture content, as shown in Table 2 . Average values of hardness resulted comparable to BR with a similar amount of moisture cooked in a pot, as shown in Fig.  2 . The storage time had a significant effect on BR hardness up to 1-year shelf life. Indeed, BR hardness decreased with increasing storage time until 120 days in all samples, and then increased at longer storage times. This trend in hardness suggests the occurrence of different events at short and long storage times and is likely related to starch structural conformation and its interaction with water. It is well known that gelatinized starch is subjected to amylopectin retrogradation and staling during storage, resulting in increase of hardness [ 26 ]. However, as previously observed [ 27 ] heating of BR in a microwave oven prior to analysis had a partial effect on reducing amylopectin retrogradation and conferred a fresh-like consistency to the product. It is possible that at longer storage times amylopectin undergoes modification that are not reversible with the microwave treatment used to warm rice. Amylopectin modification could have limited interaction between starch and water leading to decreased chain flexibility affecting gel-like texture. Further investigation at a molecular level will be necessary to better understand changes in the hardness of rice during shelf life.

Stickiness of BR was found to increase with increasing moisture level and storage time, as shown in Table 2 . Both water ( p  < 0.0001) and time ( p  < 0.0001) had a significant effect on the stickiness of rice, however, the effect of water was predominant. Rice stickiness has been correlated with its content in amylose and protein [ 28 ]. When rice is cooked in a pot, the ratio between water to rice affects stickiness between granules, with an increase of stickiness with increasing water [ 29 ] suggesting that high leaching of starch consequent to high water content affected BR stickiness. In the native starch granules, small amylopectin molecules may entangle with large amylopectin molecules by non-covalent bonding or co-crystallize with other large amylopectin molecules, at the edges of blocklets, and are free to leach once the crystalline structure is destroyed by heating [ 30 ]. An increased degree of BR cooking can result in a higher disruption of the starch granules [ 31 ] which can lead to a larger leaching of starchy components and to a consequent increase in stickiness. Higher amount of moisture might have favored amylopectin and amylose leaching, resulting in a stickier product. H bonding between larger amylopectin and other amylopectin molecules is at the base of rice stickiness [ 30 ]. Thus, higher moisture levels might have favored greater interactions among amylopectin chains, generating a denser network of H bonds and therefore leading to higher stickiness. In this study, it was not possible to make a comparison of stickiness between BR in pouch and that in pot since a small quantity of oil was added to the pouches to reduce the adhesion among kernels during cooking.

Color of BR (L, a*, b* and Δ E , Table 3 ) was found to be significantly affected by moisture content. Increasing moisture resulted in an increased L ( p  < 0.0001), and decreasing a* ( p  = 0.0033), while b* did not change significantly. These results confirm the findings of Lamberts et al. [ 32 ] but are in contrast with a previous study on BR hydration that shows decreasing levels of L at higher levels of hydration [ 33 ].

No significant effects of time were found on L and a*. On the other hand, a significant effect was observed for the values of b* with an increase in storage time leading to a lower level of b*. Furthermore, Δ E values indicate that the difference in color during the shelf life are perceptible after 40 days of storage by an untrained eye, showing values larger than 2 [ 34 ]. Pigment migration diffused from the bran into the endosperm can potentially explain the change in color during shelf life [ 32 ], or occurrence of oxidative process into the pouch altering the color of rice might be speculated. Further research will be necessary to determine what are the changes leading to decrease in yellowness in rice.

Brown rice could be a valuable ingredient in RTE meals, but the right hydration level needs to be optimized. This information was acquired using a step-by-step decision approach. Firstly, BR physiochemical properties at different hydration levels has been assessed at lab scale. From lab-scale experiments, three different hydration levels were selected and applyed for BR cooking in pouches in a pilot plant facility. It was found that, when a low moisture content (54%) identified at lab scale, was applied in the pouch, rice was not homogeneously cooked demonstrating different cooking dynamic in different environments. Conversely, higher moisture contents resulted in uniform cooking of rice kernels without affecting its microbial safety. Significant changes in texture and color were observed in brown rice during 1-year storage time, mainly related to moisture and storage time. Samples became less hard up to 120-day storage, conversely, prolonging shelf-life led to increases in hardness that might affect the product acceptability. However, further investigation will be required to better understand the cause of the physiochemical changes during shelf life of RTE pouches. A greater understanding of the textural changes in brown rice during shelf life will potentially allow to formulate new strategies to mitigate them and to successfully employ this disregarded, but nutritionally valuable ingredient, in producing RTE meals.

Gehlhar M, Regmi A (2005) Factors shaping global food markets. New directions in global food markets, 1:5–17

Shahbaz M, Bilal M, Moiz A, Zubair S, Iqbal H (2020) Food safety and COVID-19: precautionary measures to limit the spread of coronavirus at food service and retail sector. J Pure Appl Microbiol 14(suppl 1):749–756

Article   CAS   Google Scholar  

Nguyen TH, Vu DC (2020) Food delivery service during social distancing: proactively preventing or potentially spreading coronavirus disease–2019? Disaster Med Public Health Prep 14(3):e9–e10

Article   Google Scholar  

Boluda-Aguilar M, Taboada-Rodríguez A, López-Gómez A, Marín-Iniesta F, Barbosa-Cánovas GV (2013) Quick cooking rice by high hydrostatic pressure processing. LWT-Food Sci Technol 51(1):196–204

Considerations for Community-Based Organizations. Center for disease control and prevention. https://www.cdc.gov/coronavirus/2019-ncov/community/organizations/community-based.html#:~:text=There%20is%20no%20evidence%20that,family%2Dstyle%20meal . Feb 2021

Mohan V, Ruchi V, Gayathri R, Bai MR, Shobana S, Anjana R, Unnikrishnan R, Sudha V (2017) Hurdles in brown rice consumption. In: Manickavasagan A, Santhakumar C, Venkatachalapathy N (eds) brown rice. Springer, pp 255–269

Chapter   Google Scholar  

Gujral HS, Kumar V (2003) Effect of accelerated aging on the physicochemical and textural properties of brown and milled rice. J Food Eng 59(2–3):117–121

Xia Q, Green BD, Zhu Z, Li Y, Gharibzahedi SMT, Roohinejad S, Barba FJ (2019) Innovative processing techniques for altering the physicochemical properties of wholegrain brown rice ( Oryza sativa L.)–opportunities for enhancing food quality and health attributes. Crit Rev Food Sci Nutr 59(20):3349–3370

Mir SA, Bosco SJD, Shah MA (2019) Technological and nutritional properties of gluten-free snacks based on brown rice and chestnut flour. J Saudi Soc Agric Sci 18(1):89–94

Google Scholar  

Shobana S, Malleshi N, Sudha V, Spiegelman D, Hong B, Hu F, Willett W, Krishnaswamy K, Mohan V (2011) Nutritional and sensory profile of two Indian rice varieties with different degrees of polishing. Int J Food Sci Nutr 62(8):800–810

Babu PD, Subhasree R, Bhakyaraj R, Vidhyalakshmi R (2009) Brown rice-beyond the color reviving a lost health food-a review. American-Eurasian J Agron 2(2):67–72

Mir SA, Shah MA, Bosco SJD, Sunooj KV, Farooq S (2020) A review on nutritional properties, shelf life, health aspects, and consumption of brown rice in comparison with white rice. Cereal Chem 97(5):5–13

Monteiro CA, Levy RB, Claro RM, de Castro IRR, Cannon G (2010) Increasing consumption of ultra-processed foods and likely impact on human health: evidence from Brazil. Public Health Nutr 14(1):5–13

Kim S-M, Chung H-J, Lim S-T (2014) Effect of various heat treatments on rancidity and some bioactive compounds of rice bran. J Cereal Sci 60(1):243–248

Liu L, Guo J, Zhang R, Wei Z, Deng Y, Guo J, Zhang M (2015) Effect of degree of milling on phenolic profiles and cellular antioxidant activity of whole brown rice. Food Chem 185:318–325

Galanakis CM (2020) The food systems in the era of the coronavirus (COVID-19) pandemic crisis. Foods 9(4):523

Billiris M, Siebenmorgen T, Meullenet J-F, Mauromoustakos A (2012) Rice degree of milling effects on hydration, texture, sensory and energy characteristics. Part 1. Cooking using excess water. J Food Eng 113(4):559–568

Peleg M (1976) Texture profile analysis parameters obtained by an Instron universal testing machine. J Food Sci 41(3):721–722

Abràmoff MD, Magalhães PJ, Ram SJ (2004) Image processing with Image. J Biophotonics Int 11(7):36–42

Vidal V, Pons B, Brunnschweiler J, Handschin S, Rouau X, Mestres C (2007) Cooking behavior of rice in relation to kernel physicochemical and structural properties. J Agric Food Chem 55(2):336–346

Yang L, Sun Y-H, Liu Y, Mao Q, You L-X, Hou J-M, Ashraf MA (2016) Effects of leached amylose and amylopectin in rice cooking liquidon texture and structure of cooked rice. Braz Arch Biol Technol. https://doi.org/10.1590/1678-4324-2016160504

Littardi P, Diantom A, Carini E, Curti E, Boukid F, Vodovotz Y, Vittadini E (2019) A multi-scale characterisation of the durum wheat pasta cooking process. Int J Food Sci Technol 54(5):1713–1719

Schirmer M, Jekle M, Becker T (2015) Starch gelatinization and its complexity for analysis. Starch-Stärke 67(1–2):30–41

Eliasson AC (1980) Effect of water content on the gelatinization of wheat starch. Starch-Stärke 32(8):270–272

Li H, Gilbert RG (2018) Starch molecular structure: the basis for an improved understanding of cooked rice texture. Carbohydr Polym 195:9–17. https://doi.org/10.1016/j.carbpol.2018.04.065

Article   CAS   PubMed   Google Scholar  

Li H, Gilbert RG (2018) Starch molecular structure: The basis for an improved understanding of cooked rice texture. Carbohydr Polym. https://doi.org/10.1016/j.carbpol.2018.04.065

Article   PubMed   Google Scholar  

Mandala I (2005) Physical properties of fresh and frozen stored, microwave-reheated breads, containing hydrocolloids. J Food Eng 66(3):291–300

Hamaker B, Griffin V, Moldenhauer K (1991) Potential influence of a starch granule-associated protein on cooked rice stickiness. J Food Sci 56(5):1327–1329

Bett-Garber KL, Champagne ET, Ingram DA, McClung AM (2007) Influence of water-to-rice ratio on cooked rice flavor and texture. Cereal Chem 84(6):614–619. https://doi.org/10.1094/Cchem-84-6-0614

Li H, Fitzgerald MA, Prakash S, Nicholson TM, Gilbert RG (2017) The molecular structural features controlling stickiness in cooked rice, a major palatability determinant. Sci Rep 7:43713. https://doi.org/10.1038/srep43713

Article   PubMed   PubMed Central   Google Scholar  

Shamekh S, Forssell P, Suortti T, Autio K, Poutanen K (1999) Fragmentation of oat and barley starch granules during heating. J Cereal Sci 30(2):173–182

Lamberts L, De Bie E, Derycke V, Veraverbeke W, De Man W, Delcour J (2006) Effect of processing conditions on color change of brown and milled parboiled rice. Cereal Chem 83(1):80–85

Oli P, Ward R, Adhikari B, Torley P (2016) Colour change in rice during hydration: effect of hull and bran layers. J Food Eng 173:49–58

Mokrzycki W, Tatol M (2011) Colour difference∆ E-A survey. Mach Graph Vis 20(4):383–411

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Acknowledgements

The authors would like to thank Mr. Gianni De Cecchi for producing the aseptic rice pouches.

Research was partially funded by Grandi Riso S.p.A.

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Enrico Federici, Valentina Gentilucci & Valentina Bernini

Department of Food Science, Purdue University, West Lafayette, IN, 47907, USA

Enrico Federici

School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano 3, 62032, Camerino, MC, Italy

Elena Vittadini

Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via Sondrio 2/A, 33100, Udine, Italy

Nicoletta Pellegrini

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Authors NP, EV, VB contributed to the study conception and design. Material preparation, data collection and analysis were performed by EF, VG. The first draft of the manuscript was written by EF and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Correspondence to Elena Vittadini .

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Federici, E., Gentilucci, V., Bernini, V. et al. Ready to eat shelf-stable brown rice in pouches: effect of moisture content on product’s quality and stability. Eur Food Res Technol 247 , 2677–2685 (2021). https://doi.org/10.1007/s00217-021-03790-2

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Received : 23 February 2021

Revised : 25 May 2021

Accepted : 29 May 2021

Published : 15 September 2021

Issue Date : November 2021

DOI : https://doi.org/10.1007/s00217-021-03790-2

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Researchers uncover the secret to the health benefits of brown rice

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Asian diets feature rice as a staple grain, contributing towards nearly 90% of the world's rice consumption. Brown rice, in particular, is known to have several health benefits. As a regular addition to the diet, it can help reduce body weight, lower cholesterol, and suppress inflammation. The ability of brown rice to neutralize reactive oxygen species and prevent cellular damage is vital to many of its health-promoting effects. Although previous studies have shown that the antioxidant compounds in brown rice can protect cells against oxidative stress, knowledge regarding which major compound contributes towards these beneficial properties has long remained a mystery.

In a recent study led by Professor Yoshimasa Nakamura from the Graduate School of Environmental and Life Science, Okayama University, researchers from Japan have identified cycloartenyl ferulate (CAF) as the main "cytoprotective" or cell-protecting compound in brown rice. CAF is a unique compound owing to its hybrid structure. As Professor Nakamura explains, " CAF is a hybrid compound of polyphenol and phytosterol and is expected to be a potent bioactive substance with various pharmacological properties, such as antioxidant effect and blood fat-lowering effect. "

The study published on January 3, 2023 in volume 24 issue 1 of International Journal of Molecular Sciences , was co-authored by Hongyan Wu, from Dalian Polytechnic University, and Toshiyuki Nakamura, from the Graduate School of Environmental and Life Science at Okayama University. In it, the researchers provide evidence of CAF's antioxidant properties by demonstrating that it can protect cells from stress caused by hydrogen peroxide. Although hydrogen peroxide is a by-product of a cell's metabolic processes, abnormal amounts of the compound can be toxic to cells and cause irreversible damage. Treatment of cells with CAF increased their resistance to toxic stress induced by hydrogen peroxide. Moreover, CAF provided greater protection from hydrogen peroxide-induced stress compared to alpha-tocopherol and gamma-tocopherol, two other prominent antioxidant compounds that were earlier speculated to be major contributors to the antioxidant capacity of brown rice.

According to the study's estimates, the amount of CAF in the whole grain of brown rice is five-fold higher than that of other antioxidant compounds found in brown rice. Further, CAF increases the concentration of heme oxygenase-1 or HO-1, an enzyme that facilitates the production of antioxidants. " We demonstrated here that CAF significantly increased the mRNA level of HO-1, the small molecular weight antioxidant-producing enzyme, at concentrations similar to that required for cytoprotective effects in resistance to oxidative damage ," Professor Nakamura explains.

The researchers further explored this mechanism of action through experiments where blocking HO-1 activity using inhibitors reduced the antioxidant effect of CAF considerably. The high abundance and unique mechanism of action are evidence that CAF is the major contributing antioxidant in brown rice.

Through this study, the researchers have not only uncovered the secret to the health benefits of brown rice, but also locked down on the component that is majorly responsible for these benefits. This will allow the use of CAF in the development of better novel supplements and food products focused on consumer health. As an optimistic Professor Nakamura observes, " Our study can help in the development of new functional foods and supplements based on the functionality of CAFs, like CAF-based nutraceuticals. "

Although, with such naturally occurring health benefits, brown rice still very much looks to be on the menu!

Okayama University

Wu, H., et al. (2023) Cycloartenyl ferulate is the predominant compound in brown rice conferring cytoprotective potential against oxidative stress-induced cytotoxicity. International Journal of Molecular Sciences. doi.org/10.3390/ijms24010822 .

Posted in: Biochemistry

Tags: Alpha-Tocopherol , Antioxidant , Apoptosis , B Cell , Blood , Cell , Cholesterol , Compound , Consumer Health , Cytotoxicity , Diet , Enzyme , Food , Hydrogen Peroxide , Inflammation , Life science , Molecule , Oxidative Stress , Oxygen , Polyphenol , Research , Stress , Supplements

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