Abstract: The effects of pH, temperature and proportion of enzyme to substrate (E/S) on the hydrolysis of ryegrass leaf protein concentrate(LPC) with alcalase were investigated by single factors and L9(34) orthogonal test. The results indicated that the optimal pH, temperature and E/S for hydrolysis of ryegrass LPC were 10.5, 45 ℃ and 1750 units per gram respectively. The protein hydrolysate analysis was performed by high performance liquid chromatography (HPLC). There were 7 kinds of peptides. Their relative molecular weights are between 102 and 14502 and most of them are 249, accounted for 21.13%. Amino acids analysis was performed by automatic amino acid analyzer (AAAA). The total content of free amino acids in hydrolysates accounted for 3.233%. The proportion of essential amino acids to total free amino acids is 30.776%, while the proportion of sapor amino acids to total free amino acids is 38.324%, and the proportion of drug-effective amino acids to total free amino acids is 75.286%.

Key words: optimal conditions, ryegrass LPC, the component of amino acid