Characteristics of Pinctada martensii Protein Hydrolysates by Different Proteases

Pinctada martensii protein was hydrolyzed by Alcalase2.4L, Protamex, Papain, PTN6.0S, Flavorzyme500MG, Neutrase and endogenous enzymes. The hydrolysis reactions catalyzed by these enzymes were studied and the amino acids composition, molecular weight distribution and flavor evaluation of these hydrolysates were studied. Results revealed that the protein utilization, peptide yield and the degree of hydrolysis of Pinctada martensii protein by PTN6.0S and Papain were higher than those by the other enzymes, while those by endogenous enzyme were the lowest. All of the hydrolysates were rich in glutamic acid, arginine and aspartate. But different recovery of the same amino acids was found in different hydrolysates. Tryptophan, threonine, proline and aspartic acid in hydrolysates existed mainly in the form of peptides. The fractions with molecular weight of 5000 could be hydrolyzed by all the examined enzymes. The differences of the molecular weight distribution in the hydrolysates were mainly found in the peptides with molecular weight less than 3000. Among the achieved hydrolysates, the hydrolysate achieved with papain had the best taste, the weakest bitterness and fishy odor.