Preparation of antihypertensive peptides from soybean protein by enzyme hydrolysis

The high relative molecular weight fraction(HMF) in soybean protein hydrolysate produced by A.S1398 hydrolysis was further hydrolyzed by 5 kinds of proteases to produce ACE(angioensin I-converting enzyme)inhibitory peptides.The results showed that protease N was the most suitable protease,and the hydrolysis conditions were optimized as follows:mass fraction of substrate 5%,enzyme dosage 2.0%,pH 7.0,temperature 55℃.Through hydrolyzing for 120 min under the optimal conditions,the hydrolysates with degree of hydrolysis 11.1% had the most strong ACE inhibitory activity which was up to 65.1%.Fractions with high inhibitory activity were then isolated with gel chromatography.IC50 value of the fractions with the highest inhibitory activity to ACE was about 40 μg/mL.