Prepration of angiotensin I-converting enzyme inhibitory peptide from sweet potato protein by optimization of pepsin hydrolyzation
Isolation of ACE inhibitory peptide from sweet potato protein was performed by pepsin.The effect of concentration of substrate,enzyme to substrate concentration ratio,pH value and temperature on the ACE inhibition ratio was studied by optimum design of quaternary quadratic rotation orthogonality experiment to get the best enzymatic hydrolysis condition.The regression models were established between the impact factors and the ACE inhibition ratio.Results indicate that the optimal processing conditions for preparing ACE inhibitory peptides with pepsin were as follows:concentration of substrate 2.3%,enzyme to substrate concentration ratio 3.7%,pH value 2.3,temperature 37 ℃,time 8 h.Under this optimizing enzymatic hydrolysis conditions,the ACE inhibition ratio of the hydrolyzates was 78.37%.ACE inhibitory peptides were obtained from the hydrolyzates of sweet potato protein,providing the theoretical basis for the development of functional foods in prevention and treatment of hypertension.