Rheological parameters of protein interfacial layers as a criterion of thetransition from stable emulsions to microemulsions

Proteins are considered as surface active substances. On the basis of exper imentally measured rheological parameters of interfacial layers, protein ac cumulation at an interface between two immiscible liquids, isotherms of int erfacial tension, accounting theoretical ideas elaborated for multicomponen t systems, the formation of interfacial layers was referred to phase transi tion. The property of proteins to stabilise emulsions supposedly is connect ed with the formation of middle phases of lamellar structure. The correlati on between elastic properties of interfacial layers and a phase transition of the middle phase upon addition of salts or lipids has been shown. Lipids being added as cosurfactants lead to the transition from lamellar to other structures, which does not provide emulsion stabilisation. (C) 2000 Elsevi er Science B.V. All rights reserved.