Cryoprotective effect of tamarind seed polysaccharide on grass carp surimi: characteristics, interactions, and mechanisms

In surimi products, the quality deterioration caused by freezing is a common problem. Therefore, the development of natural cryoprotectants is receiving increased attention. Tamarind seed polysaccharide (TSP) has been found to have a superior ice recrystallization inhibitory effect. In this work, the cryoprotective effect of TSP on grass carp surimi was investigated, including freeze-thaw stability, water distribution, texture, and microstructure. Additionally, the interaction between TSP and myofibrillar protein was analyzed. The inclusion of TSP resulted in the formation of a more regular and compact gel network through hydrogen bonding, which enhanced the binding between water molecules and myofibrillar protein. This, in turn, immobilized free water within the gel network. Furthermore, TSP prevented the texture deterioration of the surimi gel during repeated freeze-thaw cycles, particularly when 1.0% TSP was added. Moreover, the presence of TSP delayed the decline of Ca2+-ATPase activity and stabilized the secondary, tertiary, and quaternary structure of myofibrillar protein during freeze-thaw cycles. Therefore, TSP shows promise as a potential cryoprotectant for frozen surimi products, enhancing their quality and stability during frozen storage.