Compositions, functional properties and antioxidative activity of protein hydrolysates prepared from round scad ( Decapterus maruadsi)

Abstract

Composition, functional properties and antioxidative activity of a protein hydrolysate prepared from defatted round scad ( Decapterus maruadsi) mince, using Flavourzyme, with a degree of hydrolysis (DH) of 60%, were determined. The protein hydrolysate had a high protein content (48.0%) and a high ash content (24.56%). It was brownish yellow in colour ( L ∗ = 58.00, a ∗ = 8.38, b ∗ = 28.32). The protein hydrolysate contained a high amount of essential amino acids (48.04%) and had arginine and lysine as the dominant amino acids. Na + was the predominant mineral in the hydrolysate. The protein hydrolysate had an excellent solubility (99%) and possessed interfacial properties, which were governed by their concentrations. The emulsifying activity index of the protein hydrolysate decreased with increasing concentration ( p < 0.05). Conversely, the foaming abilities increased as the hydrolysate concentrations increased ( p < 0.05). During storage at 25 °C and 4 °C for 6 weeks, the antioxidative activities and the solubility of round scad protein hydrolysate slightly decreased ( p < 0.05). Yellowness ( b ∗-value) of the protein hydrolysate became more intense as the storage time increased but the rate of increase was more pronounced at 25 °C than at 4 °C.