Effects of Ball Milling on the Properties of Colored Rice Bran

The color on the colored rice is from the rice bran. Most people eat colored rice instead of polished rice because it is believed the dark color of bran-containing substances is associated with health benefits for human beings. The bioactive phytochemicals, such as phenolic compounds that are rich in whole grains, may be a mechanism whereby whole grains have their protective effects. Rice bran is one rich source of dietary fiber and contains high concentrations of arabinoxylans (AX). In this study, ultrafine milling was applied to reduce the size of colored rice bran to improve solubility and bioaccessability. In addition to improved mouthfeel of products containing rice bran with very fine particles, the increased surface area of particles might increase the bioaccessibility of bioactive compounds in rice bran. Two major objectives of this study were (1) to evaluate the effects of dry and wet ultrafine ball-milling on the increase of the amount of water extractable arabinoxylans (WE-AX), and (2) to prepare arabinoxylan oligosaccharides (AXOS) from insoluble dietary fiber (IDF) of colored rice bran by combining ultrafine ball-milling and enzymatic hydrolysis.