The barley protein degradation: Mechanism of protein solubilization during barley mashing with neutral proteinase

Abstract

Kinetics of protein solubilization during barley mashing with neutral proteinase were studied. By plotting the kinetics data in Foster-Niemann coordinates for barley concentration range of 10-30% linear relationships with high correlation coefficients (r >/= 0. 999) were obtained. The slopes of straight lines were very close to corresponding reciprocal initial insoluble nitrogen concentrations. Barley proteolytic inhibitors affected the ordinate intercept; by their addition the values of ordinate intercept decreased. The data suggest that the modified Foster-Niemann equation can be proposed to interpret kinetics of insoluble barley protein degradation. The proteolytic activity decay was studied as well. The enzyme decay was faster in buffer solution than during barley mashing, but in both cases first-order kinetics can be applied. A mathematical model describing protein solubilization and enzyme decay kinetics were developed. The results of computer simulation were in good agreement with experimental data.