Physical And Chemical Properties Of Rice Bran Extracts And Their Enzyme Degradation

Four cell wall polysaccharides components were extracted from defatted rice bran by enzymes digestion and hydrolysis, the proximate composition, physical and chemical properties including the glycosyl profiles (Uppsala method), solubility, and viscosities were tested. Meanwhile, synergic effects of polysaccharide enzymes in the degradation of rice bran extraction mentioned above were studied. The results attempted to provide basic data for further studies to improve the nutrients utilization of rice bran.Experiment 1: The major components in the cell wall of rice bran were extracted, including SNSP₁, INSP₁, SNSP₂ and INSP₂, either adding phytase or not. The proximate composition, physical and chemical properties including the glycosyl profiles (Uppsala method), solubility, and viscosities were tested to verify their feasibility as substrate of non-starch polysaccharides (NSP) enzymes degradation. The results showed that, the extraction ratio of SNSP₁, INSP₁, SNSP₂ and INSP₂ were 5.20%, 31.72%, 1.33%, 32.97%, respectively. The SNSP₁ extract was white hardy powder, its solution was canary, and its solubility (25℃) was 4.19; The SNSP₂ extract was buff loosed powder, its solution was grey, and its solubility (25℃) was 8.60. At 40℃, the relative viscosity of 1.0% SNSP₁ and SNSP₂ solution were 1.15, 1.35, respectively. Although their proximate composition were varied significantly, the monosaccharide composing and glycosyl ratios of different extracts were remained similar to that of original rice bran.Experiment 2: Adopting orthogonal experiment methods to study the proper conditions and the synergy effect of polysaccharides hydrolyzing enzymes using rice bran polysaccharides extracts as substrate. The results showed that:â‘ to SNSP₁ and SNSP₂ extracts, the optimization pH of hydrolyzing reaction both were 4 and cellulase showed the best hydrolyzing effect. A strong synergistic effect has been observed between cellulase and pectinase, the same as cellulase and galactosidase, the synergy among other polysaccharides enzymes were all less.â‘¡to alkali-extractable INSP, the optimization pH was 5 , cellulase and endoxylanse both showed the better hydrolyzing effect. A better synergistic effect has been observed between cellulase and pectinase, the same as cellulase and galactosidase, the synergy among other polysaccharides enzymes were all less.