Natural antioxidants and antioxidant capacity of dark colored bran rice

Authors: Min, Byungrok; McClung, Anna; Chen, Ming Hsuan

Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 7/1/2009
Publication Date: 7/9/2009
Citation: Min, B., McClung, A.M., Chen, M. 2009. Natural antioxidants and antioxidant capacity of dark colored bran rice. Texas Rice, Highlighting Research in 2009. pp. VII-VIII.

Interpretive Summary:

Technical Abstract: Many medical studies have indicated that the consumption of whole grains and whole grain products is correlated with reduction of incidence of many chronic diseases such as cancer, cardiovascular diseases, and diabetes. Natural antioxidants in whole grain contribute to whole grain’s health benefits. Studies have shown that whole-grain rice contains significant amounts of natural antioxidants, mostly present in the bran fraction. These studies have mainly focused on the light brown bran rice, having the typical bran color of US rice cultivars, which contains high amounts of lipid-soluble natural antioxidants, such as vitamin E and oryzanol fractions, but very small amounts of water-soluble antioxidants. However, little information is available on the natural antioxidant profiles and capacity of dark colored bran rice, including red and purple bran rice. We have studied the natural antioxidant profiles and antioxidant capacity of red and purple bran rice, compared to those of light colored bran rice and other major cereals such as corn, oat, and wheat. In addition to their high amounts of lipid-soluble natural antioxidants, red and purple bran rice contain high amounts of water-soluble natural antioxidants and antioxidant capacity, which account for their great potential in disease prevention. Red and purple bran rice grains contain water-soluble natural antioxidant levels over 8 times higher than in light colored bran rice and other cereal grains. Purple bran rice contains very high amounts of anthocyanins, a natural colorant providing purple and red colors of fruits and vegetables. Health beneficial effects of anthocyanins, such as prevention of cancer and cardiovascular diseases, have been observed. Red bran rice contains very high amounts of tannins, which have various potential health beneficial effects. The antioxidant capacity of red and purple bran rice, measured as DPPH radical scavenging capacity, was over 10 times higher than that of light colored bran rice and other cereal grains. The antioxidant capacity likely contributes to health beneficial effects because the causes of most chronic diseases are closely related to the effects of oxidants. Therefore, dark color bran rice grains possess great potential as a source of natural antioxidants to provide beneficiary effects for human health. Furthermore, their extracts can be applied to food products as natural antioxidants to improve food quality. Many medical studies have indicated that the consumption of whole grains and whole grain products is correlated with reduction of incidence of many chronic diseases such as cancer, cardiovascular diseases, and diabetes. Natural antioxidants in whole grain contribute to whole grain’s health benefits. Studies have shown that whole-grain rice contains significant amounts of natural antioxidants, mostly present in the bran fraction. These studies have mainly focused on the light brown bran rice, having the typical bran color of US rice cultivars, which contains high amounts of lipid-soluble natural antioxidants, such as vitamin E and oryzanol fractions, but very small amounts of water-soluble antioxidants. However, little information is available on the natural antioxidant profiles and capacity of dark colored bran rice, including red and purple bran rice. We have studied the natural antioxidant profiles and antioxidant capacity of red and purple bran rice, compared to those of light colored bran rice and other major cereals such as corn, oat, and wheat. In addition to their high amounts of lipid-soluble natural antioxidants, red and purple bran rice contain high amounts of water-soluble natural antioxidants and antioxidant capacity, which account for their great potential in disease prevention. Red and purple bran rice grains contain water-soluble natural antioxidant levels over 8 times higher than in light colored bran rice and ot