ReviewHydrolysates from marine sources as cryoprotective substances in seafoods and seafood products

•Hydrolysates lowered the modification of proteins structure during frozen storage.•The formation of protein denaturation products was inhibited by marine hydrolysates.•Water molecules in frozen seafood products have been stabilized by hydrolysates.•Marine hydrolysates increased the amount of bound water in myofibrils.

BackgroundDuring freezing or frozen storage, a number of chemical changes including protein denaturation and lipid oxidation inevitably occur in seafoods. Denaturation of muscle proteins induced by freezing process is associated with deterioration, especially the loss in functional properties and consumer acceptability. To mitigate such a problem the cryoprotectants have been employed widely. Some of the widely used cryoprotectants such as sucrose impart a sweet taste in the products which consumers often consider undesirable. As a consequence, it has led to a comprehensive investigation for alternative cryoprotective substances.Scope and approachRecently, hydrolysates from different marine sources such as fish, crustaceans and cephalopods have been produced and used to maintain the quality of seafood proteins during the extended frozen storage. This review covers the recent understanding and trends in the uses of marine hydrolysates as potential alternative cryoprotectants to prevent protein denaturation in seafoods and seafood products.Key findings and conclusionsHydrolysates from chitin or proteins have been demonstrated to retard the denaturation of myofibrillar proteins by lowering the modification of proteins structure or by inhibiting the formation of denaturation products such as carbonyls and protein cross-links. Therefore, functional properties of protein associated with quality of seafoods and seafood products can be maintained. As a consequence, the potential protein/chitin hydrolysate based cryoprotectant can be widely used and the drawback of carbohydrate based cryoprotectant can be tackled.