Abstract: In order to comparatively analyze the effects of tea polyphenols and epigallocatechin gallate (EGCG), the major component of tea polyphenols, on the quality-related physicochemical properties during the processing of air-dried golden pomfret, 0.05% tea polyphenols, 0.05% EGCG and 0.02% EGCG were added to the marinade solution (8% salt), separately. The salt content, water-holding capacity (WHC), water migration, thiobarbituric acid reactive substances (TBARS) value and total volatile basic nitrogen (TVB-N) content of fish meat during curing and air drying were detected, and the change of volatile flavor substances during air-dried golden pomfret processing was analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that the addition of tea polyphenols and EGCG could effectively inhibit the increase in TVB-N and TBARS values of fish back and abdominal muscles during the curing and air-drying process (P < 0.05), and reduce the loss of immobile water, which in turn could enhance the WHC of fish meat. Among them, the effect of 0.05% tea polyphenols was the most pronounced, followed by 0.05% EGCG, and 0.02% EGCG was least effective. A total of 63 volatile components were identified during the processing of air-dried golden pomfret, among which aldehydes, ketones and esters increased during the curing and air-drying process, contributing to the unique flavor of air-dried golden pomfret. The addition of tea polyphenols and EGCG was conducive to the formation of volatile aldehydes and ketones in air-dried pomfret and reduced the content of offensive odor substances (triethylamine, butyric acid, o-phenol and isopropyl alcohol). It was found that 0.05% tea polyphenols was the most effective in improving the flavor of air-dried pomfret, followed by 0.05% EGCG, and 0.02% EGCG was least effective. This study showed that natural tea polyphenols was more effective in improving the quality of air-dried pomfret during processing than EGCG alone.

Key words: tea polyphenols; epigallocatechin gallate; air-dried golden pomfret; physicochemical properties; volatile components