CONTROL OF SURFACTANT-INDUCED DESTABILIZATION OF FOAMS THROUGH POLYPHENOL-MEDIATED PROTEIN-PROTEIN INTERACTIONS

The effectiveness of(+)-catechin in the control of foam stability of a deliberately destabilized Tween 20/beta-lactoglobulin mixed system was investigated. Significant improvement in the foamability and foam stability was obtained in the presence of low concentrations of(+)-catechin. The maximum improvement was observed at a molar ratio of (+)-catechin to protein of approximately 0.1. The mechanism of action of (+)-catechin was investigated by careful study of the properties of thin liquid films (isolated foam lamellae). This polyphenolic compound was found to increase the equilibrium thickness of the films, slow the rate of drainage, and slow the diffusion of a fluorescent probe which was located in the adsorbed layer. The data are consistent with (+)-catechin-induced cross-linking of proteins in the adsorbed layer. Such molecules offer considerable potential for the control of protein foam stability.