Abstract: Milk protein was hydrolyzed into peptides by enzyme in this research.Based on the output of peptides,the main factors that affect the hydrolyzation were experimentally studied in details.The results indicated that the output of the peptides could reach 1.82 mg/ml under the optimal conditions of the hydrolyzation temperature 45 ℃,the hydrolyzation time 2 h,the skim milk powder concentration 25%,the chymotrypsin-trypsin ratio 1:3,the complex enzyme added amount 2500 U/g,and the solution pH 8.0.

Key words: milk protein, hydrolysis, peptide