Evidence for synergy in the denaturation at the air-water interface of ovalbumin, ovotransferrin and lysozyme in ternary mixture

The conformational changes of egg-white proteins, in a ternary-protein system, at the air-water interface have been studied. Three of the major egg-white proteins, ovalbumin, ovotransferrin and lysozyme, were studied with concentration ratios reflecting those in egg-white. Results were compared to those obtained in a previous work on protein denaturation at the air-water interface in single-protein systems (Lechevalier, V., Croguennec, T., Pezennec, S., Guerin-Dubiard, C., Pasco, M., T Nau, F. (2003). Ovalbumin, ovotransferrin, lysozyme: Three model proteins for structural modifications at the air-water interface. Journal of Agricultural and Food Chemistry 51, 6354-6361). Foaming altered the protein structure more profoundly in the mixture than in single-protein systems. Strong electrostatic interactions were observed between the three proteins. Their existence at the air-water interface could ease intermolecular sulfhydryl-disulfide exchange reactions between ovalbumin and both ovotransferrin and lysozyme. This study highlighted the fact that results obtained on single-protein systems were not easily extrapolable to complex systems, such as egg-white. (c) 2004 Elsevier Ltd. All rights reserved.