Optimisation of hydrolysis conditions for yellowfin tuna (Thunnus albacares) heads using alcalase enzyme

Abstract

Abstract Fish protein hydrolysates contained small peptides and amino acids have many applications in food industry. The objective of the present study was to optimise the hydrolysis conditions (i.e., enzyme to substrate level, temperature and time) for preparing protein hydrolysates from yellowfin tuna heads using a complete composite design (CCD) of response surface methodology (RSM). The model equation was proposed with regard to the effects of enzyme to substrate level, temperature and time on the degree of hydrolysis (DH) and protein solubility (PS). The results indicated that all the hydrolysis conditions had a significant effect (P < 0.05) on both the DH and PS. An enzyme to substrate level of 0.82% (v/w), temperature of 55.0 °C and hydrolysing time of 7 h were found to be the optimum conditions to obtain the highest DH (28.0%) and PS (89.1%) using alcalase. The regression coefficients observed during both experimental and validation runs for DH and PS were 0.9381 and 0.9613, respectively, showing the validity of prediction models.