Optimizing the Enzymatic Hydrolysis of Skipjack Tuna (Katsuwonus pelamis) Dark Flesh Using Alcalase® Enzyme: A Response Surface Approach

Abstract

The goal of this study was to optimize enzymatic hydrolysis of the dark flesh of skipjack tuna (Katsuwonus pelamis). Alcalase 2.4 L was used as the hydrolytic enzyme at various concentrations (1, 1.5, 2, 2.5 and 3% w/w) at pHs from 6 to 10, temperatures from 35 to 75?C and times of 2 to 6 h. The experiment was performed following a five-level second-order central composite design with six replications at the center points. The high coefficients of determination for degree of hydrolysis (R2 = 0.8909) and free tryptophan content (R2 = 0.9732) indicate the suitability of the design for predicting the responses. The optimum hydrolytic conditions predicted by the response surface methodology were 2% Alcalase at pH 8.86 and 65.4?C for 5.74 h. These conditions resulted in an experimental degree of hydrolysis of 20.74% and free tryptophan content of 102.23 mg kg-1.