RESUMEN
The effectiveness of four cryoprotectant agents i.e. mixture of sucrose and sorbitol 8% [w/v] [S/S], sodium lactate 8% [w/v] [SL], sodium tripolyphosphate 11.8% [w/v] [STPP], and polydextrose 8% [w/v] [PDT] on protein denaturation of bolti fish fillets during freezing and frozen storage for 6 months were studied. The parameters of extractable proteins [salt and water-soluble factions], water holding capacity, total sulfhydryl content, and expressible moisture [drip under pressure] content were used to measure the protein denaturation. The used cryoprotectant agents were significantly [p<0.5] retarded protein denaturation during freezing storage [6 months]. Among all cryoprotectants used, polydextrose exhibited the greatest protective effect on protein denaturation as shown by the effectiveness in maintaining protein solubility. Sucrose/sorbitol provided more effective cryoprotection than sodium lactate in preservation of protein structure. Polydextrose and sodium lactate appeared to be promising alternative cryoportectants for fish muscle and its products owing to their low sweetness and caloric value