Characteristics of Antarctic Krill Protein Enzyme-hydrolysates

In order to compare characteristics of Antarctic krill protein enzyme-hydrolysates (KPEH), four AKPEH prepared by the meats of Antarctic krill were hydrolyzed by papain, protamex, alacalase 2.4 L, flavourzyme 500 MG, marked as PKPEH, AKPEH, FKPEH, MKPEH, respectively. Eighteen common free amino acids (FAA) were identified in four KPEHs by automatic analyzer. Leu, Arg, Val, Ala and Glu were the dominant amino acid species and hydrophobic amino acids were the main amino acid types. The total content of eighteen FAA (∑TFAA) was between 21.77~24.94 mg/mL, of which there were eight kinds of essential amino acids (EAA), and the percentage of the total content of eight EAA (∑EAA) in ∑TFAA was 48.39%~49.74%, which was higher than the EAA recommend adults and school-age enfant patterns by FAO/WHO (35.3%). And the value of fischer ratio was 2.03~3.49. AKPEH had the highest values of ∑TFAA, ∑EAA, ∑EAA/∑TFAA, whose Fischer ratio value was 3.28. The results of the amino acid taste activity value (TAV) in KPEHs showed that the content of umami and sweet amino acid components was abundant. Glu's contribution to the umami of the KPEHs was greater than that of Asp. Ala and Gly had contribution to sweetness, and Arg, His had contribution to seafood flavor. Mr distribution of KPEHs weren't continuous, of which the oligopeptides below 8 peptides in AKPEH was higher than the other three KPEHs. All the above results suggested that Alacalase 2.4 L had the highest enzymatic hydrolysis efficiency to Antarctic krill protein. The nutritional value, flavor and the biological function of AKPEH was the best. And AKPEH could be further developed as a seafood base or a functional food raw material for low molecular peptide.