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Frozen storage technology has been widely used for the preservation of Aquatic products. However, ice crystals formation, lipid oxidation and protein denaturation still easily causes aquatic products deterioration. Cryoprotectants are a series of food additives that could efficiently prolong the shelf life and guarantee the acceptability of frozen aquatic products. This review comprehensively illustrated the mechanism of protein denaturation caused by the ice crystal formation and lipid oxidation. The cryoprotective mechanism of various kinds of antifreeze agents (saccharides, phosphates, antifreeze proteins and peptides) and these cryoprotective structure-activity relationship, application efficiency on the quality of aquatic products were also discussed. Moreover, the advantages and disadvantages of each cryoprotectant are also prospected. Compared with others, antifreeze peptides show higher commercial and application values. While, lots of scientific research works are still required to develop novel antifreeze agent as a versatile ingredient with commercial value, applicable in the aquatic products preservation industry.

Effect of hydroxypropyl distarch phosphate (HPDSP) on the physicochemical properties and structure of shrimp (Penaeus vannamei) myofibrillar protein (MP) were investigated, and the changes in chemical bonds, water state, secondary structure content and protein composition of MP and MP gel (MPG) were analyzed. The results showed that the addition of 1.0% HPDSP could improve breaking force, breaking distance, gel strength and water holding capacity (WHC) of MPG, but the excessive starch could break down the structure of MPG and cause a decrease in gel quality. In addition, HPDSP had no significant effect on the relative content of MPG protein secondary structure which is consistent with the result of protein composition, while heat induction led to a decrease in the content of α-helix and an increase in the content of β-sheet and random coil. The result of the water state demonstrated that HPDSP could shorten the T2 spin-spin relaxation time of MPG and cause the exchange of water from free water to bound water. In terms of microstructure, the MPG containing 1% HPDSP had the densest three-dimensional network structure. Therefore, the overall results suggested that starch-protein interaction had the most beneficial performance of MPG with the addition of 1% HPDSP.

To investigate the effect of acetylated distarch adipate (ADA) on the physicochemical properties and structure of shrimp myofibrillar protein (MP), the changes in chemical bonds, secondary structure and protein composition of shrimp MP and MP gel (MPG) were analyzed. Besides, the microstructure, water state, texture properties and water holding capacity (WHC) of MPG with different ADA additions were compared. The results showed that the shrimp MPG with 1% ADA addition had the highest breaking force and gel strength, WHC, and the densest three-dimensional network structure. The ADA had little significant effect on the secondary structure of MP and MPG. In addition, hydrogen and ionic bonds were the main chemical bonds of MP, while MPG is mainly dominated by hydrophobic and disulfide bonds. The correlation analysis of gel properties and water state of MPG showed that bound water and immobilized water had a positive effect on the gel strength.