Study On Preparation Of Polypeptides By Enzynolysis Wheat Protein And Functional Character

This paper studied preparation of short peptides, their molecular weight distribution and their modification of functional character by controlled-enzymatic hydrolysis of wheat protein, gel chromatography and Tricine-SDS-PAGE electrophoresis techniques. At the same time, the change of amino acid content had been determined. The research contents and results in details showed as follows:1. Using wheat protein as substrate, enzyme activity was determined,pepsin was 81000U/g; and was maximum. Secondly Alcalase was 38000U/g. In ethanol body system, enzyme activity of Alcalase was very low. The solubility of wheat protein was higher under acidic or alkaline condition. TCA-SN% of pepsin and Alcalase hydrolysate was higher. Further more concentration of amino acid in enzyme hydrolysate was lower. Therefore,pepsin and Alcalase was suitable to preparate peptides by hydrolyzing wheat protein.2. Optimization hydrolysis craft condition of pepsin was as following: temperature was 41℃, pH value was 2.0, concentration of substrate was 3%, input amount of enzyme was 1500U/g, time of hydrolyasis was 7h. At the same time, Optimization hydrolysis craft condition of Alcalase was as following: temperature was 70℃, pH value was 8.0, concentration of substrate was 3%, input amount of enzyme was 1200U/g, the time of hydrolysis was 120min.3. Result of gelatin chromatographic analysis showed: Molecular weight of peptides in pepsin hydrolysate accounted for 52.4% was amount of 1500~300Da; and accounted for 18% was greater than 1500Da; and accounted for 29.5% was less than 300Da. And Molecular weight of peptides in Alcalase hydrolysate accounted for 47.1% was amount of 1500~300Da; and accounted for 21.9% was greater than 1500Da; and accounted for 31.0% was less than 300Da.4. Result of tricine-SDS-PAGE electrophoresis showed: Molecular weight of peptides in pepsin hydrolysate was mainly amount of 3.83kDa~7.47kDa; Molecular weight of peptides in...