The Health Effects and Comprehensive Utilization of Red Rice
January 17, 2024
Colored rice is a type of specific rice resource that gives rice color due to the deposition of pigments on the husk of brown rice. China is a major producer of colored rice, accounting for over 90% of the world's production.
Among the colored rice planted in China, red rice is the first and widely distributed in Yunnan, Guangxi, Hunan, Jiangxi, and Anhui.
Red rice has a red skin and a white or transparent endosperm. There are varieties such as indica, japonica, and glutinous rice, with indica sticky rice accounting for 73.8%. Red rice is rich in protein, amino acids, vitamins, trace elements, and functional components.
01The nutritional value of red rice
Research has shown that the protein content in red rice is about 11%, which is much higher than the 7% of ordinary rice; Meanwhile, the content of glutamic acid, aspartic acid, and leucine in red rice is relatively high. The essential amino acids/total amino acids and essential amino acids/non essential amino acids in red rice are 35.92% and 56.06%, respectively, which are close to the recommended pattern of FAO/WHO.
Lysine is the first limiting essential amino acid in rice, and its content determines the quality of rice protein. The lysine content in red rice is 2.14 times that of ordinary rice.
The content of trace elements such as Zn, Fe, Cu, and Mn in red rice is significantly higher than that in ordinary rice. At the same time, selenium and organic germanium are 330.77% and 20.00% higher than ordinary rice, respectively.
In addition, the content of unsaturated fatty acids in red rice is higher than that in white rice, with the main fatty acids being palmitic acid (18.34%), oleic acid (36.85%), and linoleic acid (38.04%).
02The health benefits of red rice
Some studies have shown that the consumption of colored rice can reduce the incidence rate of chronic diseases such as cardiovascular disease, type 2 diabetes, obesity, etc.
2.1 Lowering cholesterol
Chen Qixuan and others added red rice and regular rice to a high-fat and high cholesterol mixed feed to feed New Zealand rabbits, and found that red rice can promote cholesterol reverse transport, clear cholesterol in the body, and reduce the area of aortic lipid plaques.
2.2 Hypoglycemia
There are reports showing that different processing methods can have an impact on the hypoglycemic effect of red rice. Kaur et al. pointed out that adding butter during or before steaming red rice can increase the content of resistant starch and inhibit postprandial blood sugar elevation.
Somaratne et al. studied the effect of polishing degree on the glycemic index of red and white rice, and found that the glycemic index of red rice was significantly lower than that of white rice, and the polishing degree was positively correlated with the glycemic index.
2.3 Weight loss
Red rice has a weight control effect, partly because it contains about 1.11% dietary fiber, which is higher than ordinary rice and gives people a stronger sense of fullness; On the other hand, the polyphenols contained in red rice also have an inhibitory effect on fat absorption.
2.4 Anti inflammatory and antioxidant effects
Callcott et al. found that polyphenol extracts from red rice can reduce plasma levels of malondialdehyde and TNF in obese individuals- α The concentration of has anti-inflammatory and antioxidant effects.
03 Comprehensive utilization of red rice
3.1 Formula Rice
Formula rice is generally aimed at improving sensory quality and enriching nutritional characteristics, and is made by mixing different varieties of rice in a certain proportion.
Red rice is rich in nutrients such as protein, amino acids, and minerals, especially phenolic substances, and its nutritional value is higher than refined white rice.
Therefore, combining red rice and polished white rice can improve the sensory characteristics of red rice, such as its hard taste and poor adhesion, while also enhancing its nutritional value. Generally, the ratio of red rice to polished rice is 15:85 or 10:90.
3.2 Sprouting Red Rice
Sprouting red rice is a product obtained by culturing red rice under certain conditions, germinating to a certain extent, and then inactivating and drying it.
During the germination process, endogenous enzymes in red rice are activated, greatly increasing the content of nutrients and bioactive substances. At the same time, the cortex is partially decomposed, making the texture softer and effectively improving its digestibility.
Wang Yan et al. found that as the germination time increased, the content of free amino acids continued to rise, reaching its maximum at 96 hours. The percentage of essential amino acids in the total free amino acids increased from 20.3% to 48.0%, the content of lysine increased from 1.4% to 5.3%, and the GABA was 14.2 times that of non germinated red rice; Further research on the antioxidant activity of sprouted red rice revealed that compared to non sprouted red rice, the total phenolic content and DPPH clearance rate of sprouted red rice increased by 1.1 times, while the content of ferulic acid and p-coumaric acid significantly increased.
3.3 Red rice bran
Rice bran is composed of rice husks and rice embryos that fall off during the whitening process of brown rice, while most of the minerals, pigments, and bioactive substances in red rice exist in the husks and rice embryos.
Wang Jinying and others found that the Se, Cu, Fe, Zn, Ca, and Mn in red rice bran are 2.35, 6.20, 10.36, 3.22, 4.85, and 12.44 times higher than those in polished rice, respectively.
04 Red Rice Food Development
In recent years, people's attention to healthy food has been increasing, and there are more and more foods made from red rice as raw material. Infancy is a critical stage of human growth and development. Research has found that active oxidants are prone to damage the cells of infants and cause diseases. Adding red rice Rice noodles to Rice noodles for infants aged 4-6 months can make it have antioxidant effect.
Estuti et al. developed a cream soup suitable for menopausal women using black beans and red rice, with a total isoflavone content of 162.59 μ G/g, anthocyanin content is 254.58 μ G/g, with an antioxidant capacity of 723.73mg/100g.
Zhang Xiaohua et al. used red rice as an adjunct to make beer, which not only retained the taste of the beer but also increased the content of flavonoids and niacinamide in the beer.
Li Min et al. studied the production process of red rice wine using red rice and raisins as raw materials. The red rice wine was fermented at 28 ℃ for 48 hours with 20% raisins, 30% red rice, 1.0% inoculum, and the color was slightly red, the taste was mellow, and the sensory score was the highest.
Wei Zhencheng et al. created a red rice beverage with a 0.04% addition of high-temperature amylase. After 12 minutes of enzymatic hydrolysis at 100 ℃, a light red, well tasting, uniform and non layered beverage was obtained. The stabilizers were agar 0.05%, sodium alginate 0.05%, xanthan gum 0.05%, and alginate propanol ester 0.05.
Yu Fei et al. found that the optimal process for the red rice pumpkin composite beverage is 5% red rice addition, 9.4% -9.5% pumpkin addition, 18% milk addition, 8.0% -8.15% sucrose addition, and 0.5% composite stabilizer.
Hu Hai'e studied the technology of red rice and pumpkin Congee, and obtained 60g white granulated sugar, 80g red rice, 80g glutinous rice, 1.0g compound stabilizer, 1000mL water, and 200g pumpkin, which can be used to make pumpkin red rice porridge with sweet, soft, uniform shape and pure flavor.
05 Conclusion and Outlook
At present, the comprehensive utilization of red rice is not yet widespread enough, and there are still several problems in the following aspects:
① The bioactive substances contained in red rice are mainly distributed in the outer layer of the seed cortex, which has a high content of cellulose. During processing and utilization, on the one hand, it hinders water from entering the starch, making it unable to fully gelatinize, and on the other hand, the presence of fiber leads to a deterioration in its taste. Therefore, how to use processing technology or biological enzyme technology to improve the sensory quality of red rice while retaining its functional components remains to be studied.
② There have been reports showing that red rice has various health benefits, but most of them are still at the level of animal experiments, with few reports on human experiments. Given the differences between the human digestive system and animals, further research is needed to demonstrate the health benefits of red rice through human experiments.
③ Red rice pigment is a natural antioxidant, mainly composed of anthocyanins, which have poor stability. Further research is needed to improve the stability of red rice pigment in food.
