Optimization of Technology for Preparation of Angiotensin-converting Enzyme Inhibitory Peptides from Silkworm Pupal Protein by Enzymatic Hydrolysis

Hydrolysis of silkworm pupal proteins with alcalase for preparation of angiotensin-converting enzyme(ACE) inhibitory peptides is one of the important ways to have in depth utilization of silkworm pupal proteins.Taking ACE-inhibitory rate as the response value,effects of hydrolysis temperature,hydrolysis pH,and enzyme dosage on ACE-inhibitory activity of the hydrolysates were analyzed with response surface methodology for optimization of the preparation technology.The results showed that importance of the three factors affecting activity of ACE-inhibitory peptides from high to low was in the order of hydrolysis pH,hydrolysis temperature,and enzyme dosage.The optimized process parameters for preparation of angiotensin-converting enzyme(ACE) inhibitory peptides from alcalase hydrolyzed silkworm pupal proteins were as follows: hydrolysis temperature 50.8 ℃,hydrolysis pH 9.0,and enzyme dosage 3 500 U/g.Under this condition,the highest ACE-inhibitory rate of the hydrolysate from silkworm pupal proteins was 96.67% in theory and the actual value was 96.49%±1.75%,IC50 value was 0.102 mg/mL.The result indicates that the established prediction model is reliable and is applicable to enzymatic preparation of ACE-inhibitory peptides from silkworm pupal proteins.