Physicochemical Characteristics and Bacteriostatic Ability of Modified Lysozyme From Lactic Acid-Induced Gelled Egg White Powder

Abstract

This study investigates the physicochemical characteristics and bacteriostatic ability of modified lysozyme from 6, 7, 8, 9 and 10% lactic acid-induced gelled egg white powder. The lactic acid modified lysozyme (LAML) powder was dissolved in solutions with pH values of 2-10 at incubation times of 30-720 min, showing enzymatic activity of 50% (2,000-6,000 U/mg). Following treatment in solutions of various concentrations of salt (0.1-3 M), the activity of LAML decreased with an increase in the concentration of salt. The enzymatic activity of LAML decreased with an increase in temperature (40-100C) and incubation time (10-120 min); the activity of LAML ceased when held at 100C for 120 min. The LAML showed quantities of a dimmer (28 kDa) structure appearing in native-polyacrylamide gel electrophoresis analysis. The bacteriostatic efficacy of LAML against Bacillus cereus BCRC 15324, Escherichia coli K12 and Salmonella typhimurium TA98 increased proportionally with the concentration of LAML solution. This study revealed that LAML has bacteriostatic ability against E. coli K12, S. typhimurium TA98 and B. cereus BCRC 15324 while maintaining enzymatic activity under a variety of conditions. PRACTICAL APPLICATIONSLysozyme from the egg whites from hens is an enzyme comprising approximately 3.4% of egg white protein. Lysozyme demonstrates strong antibacterial potential, mainly among gram-positive bacteria, and this phenomenon has found practical applications in the food and pharmaceutical industries. However, gram-negative bacteria are less susceptible to lysozyme activity.Various researchers have identified a synergistic relationship between lysozyme and other preservatives such as organic acids, resulting in significantly improved bacteriostatic activity against a wide range of bacteria. The present work shows that the enzymatic activity of the modified lysozyme with various concentrations of lactic acid solution remains stable while maintaining consistent bacteriostatic activity against Bacillus cereus BCRC 15324, Escherichia coli K12 and Salmonella typhimurium TA98. Lactic acid-induced gelled egg white powder represents a cost-effective alternative to the standard bacteriostatic additives used in the food industry.