Thermal gelation of whey protein at different pH values

Gelation is an important functional property of whey proteins. Their ability to form heat induced gels and provide appropriate texture is determined by its molecular structure (primary, secondary, tertiary, quaternary), interactions with other components (salts, acids, urea) and processing conditions (pH, ionic strength, heating temperature, heating and cooling rate). The objective of this work was to define gel texture changes of whey protein isolates (WPI) at various pH values in function of following processing operations: tribomechanical activation and enzymatic hydrolysis. Whey protein gels were prepared by heating dispersions of two commercial powdered whey protein isolates before and after tribomechanical activation and enzymatic hydrolysis, respectively. The results obtained showed that tribomechanical activation as well as enzymatic hydrolysis influenced the gelation ability. Texture of gels was affected by pH. Gels prepared at pH 3 showed higher hardness than gels at pH 7. This work suggests that desired modification of gel texture can be achieved in order to enhance the suitability of WPI for incorporation into various processed and formulated food products. Copyright © 2009, AIDIC Servizi S.r.l.