Tea polysaccharides improved the water mobility, thermal stability and microstructural changes of Hypophthalmichthys molitrix surimi during frozen thaw cycles

This study aimed to evaluate the protective effect of tea polysaccharides (TPR) on surimi quality during freeze–thaw cycles (FTC). Although TPR has shown cryoprotective potential, its effects on water mobility, thermal transitions, and protein interaction profiles in surimi under repeated FTC conditions remain unclear. Surimi and myofibrillar proteins were treated with TPR at 1% and 3%, an industrial mixture (CP), or no treatment (C) during FTC. In C samples, the gel strength decreased from 3043.38 to 1078.82 g·mm, with shifts in T21 and T22 relaxation behavior and Tg. Compared with TPR (1%), CP exhibited greater stability in Tg, T21/T22 relaxation behavior, and ΔH. Notably, TPR (3%) maintained water-state stability, gel strength, thermal stability, and an operational protein interaction profile under the FTC conditions. These findings suggest that 3% TPR may serve as a promising natural cryoprotectant for improving surimi quality during FTC.