Effects of Chemical, Biochemical and Physical Treatments on the Kinetics and on the Role of Some Endogenous Enzymes Action of Baker’s Yeast Lysis for Food-Grade Yeast Extract Production

Abstract

The effects of chemical, biochemical and physical treatments on lysis of baker’s yeast cells were studied at pH 5.2 and temperature 54 °C. An unstructured kinetic model of first order was developed to understand the mechanism of yeast lysis. The autolysis rate constant (k), yield factor for protein (β_P), total carbohydrate (β_C) and autolysate (α_A) were sensitive to disruption methods. Since there were endogenous enzymes in the yeast cells such as proteinases, glucanases and carboxypeptidases, these enzymes were responsible for synergistic of cell disruption and their activity profiles were affected by different treating methods. From the determined results of amino acids composition in yeast autolysate, there were differences in amino acid content. The biochemical treated sample using 0.1% papain gave the highest total amino acid content among all analysed samples.