Evidence for synergy in the denaturation at the air-water interface of ovalbumine, ovotransferrin and lysozyme in ternary mixture
Résumé
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., Guérin-Dubiard, C., Pasco, M., & 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.