Optimization of enzymatic hydrolysis condition and functional properties of eel (Monopterus sp.) protein using response surface methodology (RSM)

Abstract

The present study aims to optimize the enzymatic hydrolysis condition and determine the functional properties of eel (Monopterus albus) protein hydrolysate (EPH) at different hydrolysate concentrations (0.1%, 0.5%, 1.0%). The enzymatic hydrolysis (using alcalase) condition; namely, temperature (°C), enzyme to substrate concentration (%) and pH on both the yield and degree of hydrolysis (DH), as responses, was optimized using the response surface methodology (RSM) by employing three factors, 3-level, Central Composite Design (CCD). The optimum hydrolysis condition suggested was a temperature of 55.76 °C, enzyme concentration of 1.80% and pH of 9. The experimental result for yield (9.45%) was higher while the experimental result for DH (15.01%) was lower than the predicted values of the responses using the quadratic model, which were 5.67% and 16.73%, respectively. The findings for the functional properties showed that the Nitrogen Solubility Index (NSI) of EPH was 85%. The emulsion stability index (ESI) of EPH was shown to decrease with the increase hydrolysate concentration (0.1%, 0.5%, 1.0%) while the foam expansion of EPH showed an increase with the increase in concentration. High solubility and the ability of EPH to emulsify and form foam show its potential for use as a natural binding and emulsifying agent