Preparation of Antihypertensive Peptide from Hydrolyzing Peanut Protein by Trypsin Covalently Immobilized on Chemically Modified Chitosan-coated Fe_3O_4 Particles

摘要

The aim of this study was mainly on apply immobilized trypsin which covalently linked with chemically modified chitosan-coated Fe_3O_4 particles to producing the antihypertensive peptide by hydrolyzing peanut protein. Response Surface Methodology (RSM) was employed to optimize the hydrolysis conditions, including Enzyme/substrate ratio, temperature, pH and time. Results showed that enzyme immobilization technology improved the thermal and pH stability of trypsin. The minimum IC_(50) value for Angiotensin Converting Enzyme (ACE) inhibitory activity (0.76 mg/mL) was obtained at the E/S ratio of 3.52, the temperature of 54.65°C, the time of 2.95 h and pH of 8.43, which was agreement with the predicted value (0.77 mg/mL) estimated by RSM within a 95% confidence interval. Moreover, a modest increase in the degree of hydrolysis promoted the ACE inhibitory activity of the hydrolysates, but excessive hydrolysis would lead to a decrease in ACE inhibitory activity.