Interaction of Tea Polyphenols with Whey Protein and Foam Properties of Resulting Complexes

Abstract:

In the processing of foods containing polyphenols and whey protein, both components interact, which has a great influence on the foam properties of whey protein itself. Using whey protein isolation (WPI) and tea polyphenols (TP) as raw materials, the interactions of TP with WPI and heated WPI (HWPI) were investigated, and the effects of the TP concentration, pH, salt ions, and temperature on the foam properties of the resulting TP/WPI and TP/HWPI complexes were evaluated. The interaction between TP and HWPI was stronger than that of the former with WPI. Insoluble complexes were formed between TP and WPI (or HWPI) when TP was present at a high concentration (7.5 mg/mL). At TP concentrations of 2.5 and 1.25 mg/mL, respectively, TP/WPI and TP/HWPI both exhibited the best foam properties, with a corresponding foam capacity of 94.51% and 95.11%, and foam stability of 272.32% and 276.70%. At pH 5.0 and 4.0, respectively, TP/WPI and TP/HWPI both showed the best foam properties, with a corresponding foam capacity of 92.50% and 97.82%, and foam stability of 276.73% and 298.33%. The foaming properties of TP/WPI and TP/HWPI degraded with increasing salt (ion) concentration, but those of TP/HWPI were less affected. Compared with TP/WPI, temperature had less effect on the foaming ability of TP/HWPI. Therefore, the addition of TP at a low concentration could form TP/HWPI complexes with good foam properties. This study provides a reference for processing milk-protein-related foamed food.