Alkali‐induced aggregation behaviour of tea polyphenols and its gel strengthening mechanism to alkali‐induced egg white

Summary The effect of black and green tea extracts with different alkali induction degrees on gel properties of alkali‐induced egg white gels (EWGs) was evaluated. Results indicate that, with the increase in alkali induction time, the concentration of soluble polyphenols gradually decreases while their relative polymerisation degree increases, especially for black tea polyphenols. The addition of tea extracts, especially induced by alkaline treatment for 6, 12, and 24 h, can promote the coagulation and browning and inhibit the ‘alkali injury liquefaction’ of alkali‐induced EWGs. Additionally, under alkali‐induced conditions, polyphenols in tea, especially black tea, can enhance the textural properties and thermal stability of alkali‐induced EWGs, this enhancement reaches its peak at 12 h of alkali induction and is consistent with protein secondary structure and interaction forces results. This research provides theoretical support for selection and induction of tea in high‐gel‐strength preserved eggs and other alkali‐induced protein gel food processing.