Antifreeze polysaccharides as natural cryoprotectants for frozen meat and seafood products: Mechanisms, evaluation methods, and future prospects.

Freezing is widely employed to preserve meat and seafood products, yet ice recrystallization during frozen storage and thawing disrupts muscle ultrastructure, denatures myofibrillar proteins, and elevates drip loss. Conventional carbohydrate cryoprotectants, such as sucrose, sorbitol, and trehalose, stabilize myofibrillar proteins by modulating water activity, glass transition behavior, and hydrogen-bonding networks. Natural polysaccharides have emerged as promising alternatives that deliver cryoprotection while offering lower sweetness and reduced caloric contribution compared with conventional carbohydrate-based cryoprotectants. This review examines recent advances in applying these polysaccharides as cryoprotectants in comminuted matrices and intact muscle tissues and delineates four interrelated mechanisms: (1) Polysaccharide hydroxyl groups form hydrogen bonds with polar side chains of myofibrillar proteins, sterically limiting unfolding and disulfide-mediated aggregation induced by freeze-thaw cycling. (2) Extensive polysaccharide-water hydrogen bonding disrupts the tetrahedral network of water hydrogen bonds, reduces the fraction of freezable water, and elevates the energy barrier for ice nucleation. (3) Polysaccharide segments adsorb onto ice crystal surfaces, introducing local curvature that inhibits crystal growth through the Gibbs-Thomson effect. (4) Extended high molecular weight chains with an appropriate hydrophilic-hydrophobic balance restrict interfacial water migration, thereby inhibiting recrystallization. The efficacy of an antifreeze polysaccharide depends on its molecular weight, chain rigidity, degree of branching, hydrophilic-hydrophobic balance, and aggregation state. Current evaluation methodologies are compared, including direct and indirect ice crystal visualization, molecular dynamics simulations, thermal hysteresis analysis, and spectroscopic probing of hydrogen bonding. Unresolved questions concerning structure-activity relationships, polysaccharide-protein co-network architecture, and simulation tools suitable for complex food matrices are discussed.