Effects of Different Natural Plant Polyphenols on the Eating Quality of Pre-prepared Grilled Fish during Repeated Freeze-Thaw Cycles

To investigate the effects of five plant polyphenols (tea polyphenols, resveratrol, apple polyphenols, grape seed polyphenols, and curcumin) on the eating quality of pre-prepared grilled fish during repeated freeze-thaw cycles, polyphenol immersion pretreatment combined with roasting and five freeze-thaw cycles was applied to simulate cold chain temperature fluctuations. Quality was evaluated by measuring changes in appearance, water-holding capacity, texture, thiobarbituric acid reactive substances (TBARS), acid value (AV), and DPPH radical scavenging activity, systematically assessing polyphenols antioxidant capacity and their impact on product quality. Results indicated that all polyphenol treatments improved appearance stability after five freeze-thaw cycles, with apple and grape seed polyphenols exhibiting superior color retention. Both also significantly enhanced water-holding capacity (P<0.05), outperforming other groups. Texture profile analysis showed that resveratrol performed well in maintaining the chewiness and springiness of the samples, apple polyphenols contributed to the retention of chewiness, whereas tea polyphenols showed no obvious advantage in chewiness. For lipid oxidation, TBARS values in all polyphenol groups were significantly lower than the control (P<0.05), with apple polyphenols showing the greatest reduction (67.18%), followed by grape seed polyphenols (57.33%), resveratrol (50.33%), tea polyphenols (48.21%), and curcumin (15.75%). Grape seed polyphenols also most effectively suppressed AV (46.89% reduction, P<0.05). DPPH scavenging activity increased most significantly with apple polyphenols (42.79%), followed by grape seed polyphenols (36.53%) and resveratrol (35.09%), confirming strong antioxidant potential. Overall, apple and grape seed polyphenols demonstrated superior quality preservation and lipid oxidation inhibition. Considering antioxidant efficacy, product quality, and cost, grape seed polyphenols were identified as the optimal natural antioxidant. This study provides theoretical and technical support for quality control and formulation optimization of pre-prepared grilled fish during cold chain distribution.