Optimisation of the enzymatic hydrolysis of oneknife unicornfish, naso thynnoides (Cuvier 1829) skin gelatin

Abstract

Protein hydrolysates are products of splitting protein into peptides, which has been shown to provide superior nutritive benefits than the parent material. Hydrolysis can be carried out enzymatically or by using acid or alkali treatments. In this study, conditions for enzymatic hydrolysis of unicornfish Naso thynnoides (Cuvier 1829) skin gelatin was optimised through response surface methodology (RSM) to yield the highest degree of hydrolysis. Extracted skin gelatin was hydrolysed using a crude preparation of neutral protease from Bacillus sp. The considered optimum hydrolysis conditions were: enzyme concentration of 2.11 % (v/v), the temperature of 47.60 °C and hydrolysis time of 137.45 min resulting in 29.12 % degree of hydrolysis (DH) point prediction value. Foaming capacity expressed as foaming expansion percentage (FE) was also considered as a surface model response. Response surface methodology predicted an optimum FE value of 11.14 % with optimal conditions as follows: enzyme concentration of 2.13 % (v/v), the temperature of 54.16 °C and hydrolysis time of 147.73 min.