Aggregation of hen egg white proteins with additives during agitation

Abstract

Aggregation of hen egg white proteins (HEWPs) is an important issue in the production of egg products in the food industry. The aggregation of HEWPs during agitation is caused by the gas–liquid interface denaturation of proteins, which is different from their thermal aggregation. In this study, we investigated the mechanism of aggregation and the co-aggregation of HEWPs induced by agitation in the presence of additives. The aggregation of HEWPs caused by agitation was suppressed by amphiphilic surfactant and amphiphilic additives, rather than by the well-known aggregation suppressor, arginine. Lysozyme (LYZ) and ovalbumin (OVA) dramatically formed co-aggregates that were stabilized by disulfide bonding with denatured lysozyme during agitation. In contrast, lysozyme and ovotransferrin (OVT) formed co-aggregates to a lower extent than that observed for OVA, due to the weak interaction between these two proteins. These data indicate that the electrostatic attraction and disulfide exchange between LYZ and OVA play critical roles in the co-aggregation of HEWPs during agitation. This article proposes not only the theory and techniques that may become the basis of an appropriate processing method for safer pasteurization and transportation of HEWPs but also provides information about the aggregation of mixed proteins used in various fields.