Investigation of Calcium-Binding Capacity and Functional Properties of Acetes Japonicus Protein Hydrolysate

Abstract

Calcium-binding capacity (CaBC), amino acid profile and functional properties of proteolysate derived from Acetes japonicus were evaluated in this research. Firstly, effect of hydrolysis parameters including enzyme type, enzyme to substrate (E:S) ratio and hydrolysis time on the CaBC of the proteolysate was examined using single factor test method. Then, amino acid component and technological features involving solubility, heat stability, foaming and emulsifying property, oil holding capacity (OHC) and water holding capacity (WHC) of the protein hydrolysate were assessed. The result showed that the proteolysate exhibited the greatest CaBC of 261.61 ± 3.89 mg Ca2+/g protein, 1.77 folds lower than that of casein phosphopeptide, under the hydrolysis condition encompassing Flavourzyme, pH 6.5, 50 C, E:S ratio of 60 U/g protein and hydrolysis time of 5 hours. Solvability and heat stability of the proteolysate achieved over 75 % and over 70 % in the pH range from 5 to 8 The foaming capacity (FC), foaming stability (FS), emulsifying activity index (EAI) and emulsifying stability index (ESI) reached the peaks of 46.33 ± 0.57 %, 40.22 ± 0.38 %, 15.92 ± 0.07 m2/g and 48.06 ± 1.59 min at pH 8. The OHC and WHC of the proteolysate accomplished 4.76 ± 0.41 ml oil/g proteolysate powder and 2.81 ± 0.08 ml water/g proteolysate powder. The proteolysate contained 8 out of 9 essential amino acids for human, comprising approximately 45 % of total amino acid content. On the whole, the proteolysate could be served for calcium enhancement which could protect human body from disorders caused by calcium shortage or as a functional protein preparation to improve food properties. The findings likewise increase the economic value for the small shrimp which is quite cheap in Vietnam.