Preparation of peptides hydrolyzed from rape pollen glutelin

Protein fractionations of cell-fragmentated and defatted rape pollen stored for more than 12 months were investigated. Rape pollen glutelin was hydrolyzed with alcalase and the crude peptides of rape pollen were obtained. The scavenging effects of rape pollen glutelin and its hydrolysate on hydroxyl free radicals (?OH) in the deoxyribose-iron system was studied. Results show that glutelins and albumins are found to be the predominant proteins in rape pollen, accounting for 55.7% and 39.0% of total proteins, while globulins and prolamins are 3.2% and 2.1%, respectively. The optimum conditions of alcalase enzymatic hydrolysis were determined by single-factor analysis and response surface methodology as follows: pH9, hydrolyzing temperature 50℃, enzyme concentration 1460 U per gram of substrate, concentration of substrate 6%, hydrolyzing time 2 h. In the antioxidation test, the inhibition rate ?OH of glutelin was 25.1%. After being hydrolyzed, the inhibition rate of ?OH of glutelin oligopeptide was remarkably increased to reach 70.0%.