Effect of high pressure-assisted crosslinking of ovalbumin and egg white by transglutaminase on their potential allergenicity

Abstract

Abstract Transglutaminase (TG) modifies proteins by amine incorporation, crosslinking and deamination. It is used as an important tool in food processing. The aim of this work was to crosslink ovalbumin (OVA) and egg white (EW) with TG, either under high pressure (HP) or under atmospheric pressure on previously HP-treated proteins, to assess the allergenic potential of polymerized allergens. The susceptibility of OVA and EW to TG-mediated crosslinking was enhanced by HP (400 MPa, 40 °C, 30 min). Simultaneous or sequential HP and TG treatments led to the formation of high-molecular weight polymers, but left a substantial amount of monomeric proteins. Results of digestibility experiments, binding to immunoglobulin E (IgE) from egg allergic patients and stimulation of spleen and mesenteric lymph node cell cultures of EW-sensitized BALB/c mice showed that resistance to proteolysis, IgE-binding and immunostimulatory properties of the HP and TG-treated proteins were not substantially different from those of the native ones. Industrial Relevance The use of transglutaminase as a crosslinking agent has been suggested for many industrial applications, as in the case of meat, fish, milk or soy proteins, which are good substrates for this enzyme. This work widens the possible use of transglutaminase, for modifying less suitable substrates for crosslinking, as egg proteins, through the use of high pressure before or during crosslinking. In our study, HP-assisted TG-induced OVA and EW crosslinking enhanced gastroduodenal digestion but did not reduce the allergenicity of egg proteins.