Kinetic model of the hydrolysis of egg white proteins by Alcalase

Abstract

The kinetics of hydrolysis of egg white proteins by Alcalase 2.4L (protease from Bacillus licheniformis) was investigated. In this paper, the main objective was to determine the appropriate empirical model for the proteolytic hydrolysis of egg white. A logarithmic equation X = (1/b) ln (1 + abt) indicating the relationship between the degree of hydrolysis (DH) and time was established. Experimental data were successfully fitted with kinetic model taking into account the enzyme inactivation and substrate inhibition, and related kinetic constants were determined. The kinetic study was performed at optimum process parameters: initial enzyme concentration of Alcalase 2.4L, initial substrate concentration of the egg white proteins and different temperatures of the reaction. The kinetic and thermodynamic constants for reaction of hydrolysis (Ki = 320.07 mg cm-3, k2 =0.0104 min-1, kd = 0.0743 min-1, Ea = 103.04 kJ mol-1, Ed = 99.52 kJ mol-1) were responsible for the empirical equation. Kinetic constants of the hydrolysis were determined, and good congruence between the model and experimental data was achieved. The results of nonlinear regression of the proposed kinetic model agreed with the experimental data, thus the kinetic equations can be used to fit the enzymatic hydrolysis process of egg white protein and to optimize the operating parameters for the bioreactor design.