Studies On The Preparation And Properties Of Antioxidant Peptide From Rice Residue

Rice residue is by-product of rice syrup and fermentation industry which uses rice as raw material, its contents over 60% protein. Currently, the rice residue is mainly used as a low-quality and cheap protein resources to feed the animals, the rice proteins are not sufficiently comprehensive utilization. So, developing some ways to utilization, not only can reduce this resource waste, but also can create more values and bring new growth point in Agriculture and economic development. In this study. we use the rice residue as raw material, rice peptides were obtained from a reaction by protease trypsin hydrolysis process of rice residue and optimize the trypsin hydrolysis conditions, then studied on the antioxidant activity of the antioxidant peptides, its physical and chemical, nutritional characteristics and functions and its effects on the growth and immune of weanling mice are also studied in this research.Results as follows:1. The reducing power as index, typsin was chosen as the best enzyme in preparing antioxidant peptides from the tested four proteases. The optimal process parameters were obtainded through the typical analysis and ridge analysis as follows: pH 7.56,52℃, solid-liquid ratio 9,2 h. In this condition, the reducing activity of the antioxidant peptides (absorbance) can reach 0.6888.2. The antioxidant peptides shows high antioxidant activity in vitro antioxidant system; The peptides had a scavenging activity on the hydroxyl radical, superoxide anion radical and DPPH radical in a dose-dependent manner, IC50 is 4.267 mg/ml,2.911 mg/ml,4.964 mg/ml, respectively. It also shows some inhabitant on the peroxidation of linoleic acid emulsion system.3. The short chain of peptides content was 74.27%, main distribution of molecular weight under 3000Da, the average diameter is smaller than the initial rice residue particle diameter, about 1/6; comparing to rice protein, physiological activities of its hydrolysates including solubility, emulsifying activity, surface hydrophobicity significantly improve; glutamic acid was the most abundant amino acid by amino acid analysis of rice peptides, followed by aspartic acid; limited amino acid contained tryptophan and lysine. The essential amino acid is the most abundant, its amount up to 39.99%.4. The effects of rice peptides on the growth performance and immune of weaned mouse are also studied in this research, soybean meal protein and rice residue protein as control assay. The results indicate the rice antioxidant peptides have significant effort on improving rats gain and feed conversion efficiency, it also can better promote the diet away from the rat intestinal absorption, rat intestinal immune function and antioxidant activity of the small intestine submucosa.