Preparation of Anti-Diabetic Activity Peptides from Pumpkin Seeds Against Alpha-Glucosidase

The prevalence of diabetes mellitus and obesity is rapidly rising worldwide. This study investigated the inhibition efficiency of peptides hydrolyzed from pumpkin seeds on α-glucosidase using an in vitro method. In this research, pumpkin seeds protein isolate was hydrolyzed by using Alcalase, chosen from 4 kind of proteases. The hydrolysis conditions was optimized through response surface method (RSM) in order to achieve the maximum α-glucosidase inhibitory activity. The effects of hydrolysis conditions including time, temperature, enzyme/substrate, substrate concentration and pH. RSM efficiently identified the critical levels of each variable to obtain maximum α-glucosidase inhibitory activity. It was shown that hydrolysate prepared at 53.5°C, E/S=2.8%, S%=5.2% and pH 10.4 resulting from hydrolysis for 2h exerted 56.7% α-glucosidase inhibitory activity and 18.3% hydrolysis degree. The amino acid composition and molecular weight distribution of the anti-diabetes peptides were also determined.