Rheology of heat-set pudding (emulsion gel) and O/W interface: effects of interaction between tea catechins and egg yolk plasma at O/W interface

Abstract

Herein, the effects of tea catechins (TCs) on the rheological properties of a model heat-set pudding (emulsion gel) were investigated. A combination of skimmed milk powder, egg white powder, egg yolk, egg yolk plasma, egg yolk granules, coconut oil, and TCs was used as the raw material for the model pudding. Viscoelastic measurements showed that the storage modulus G′ of the TC-containing model pudding in the range of 10°C–15°C (each solid fat content in coconut oil ranged from 79% to 71%) was approximately 10-fold higher than that of the model pudding without TCs. Furthermore, a very high Gʹ could be obtained when egg yolk plasma and coconut oil were used in the raw material for the TC-containing model pudding at 10°C–15°C. Additionally, the results of interfacial tension and viscoelasticity measurements at the oil-water interface suggested that the interfacial structure changes due to the interaction between egg yolk plasma and TCs contributed to a very high G′ for the TCs-containing model pudding in the range of 10°C–15°C.