Trypsin Treatment to Improve Freeze Texturization of Minced Bream

Mild trypsin proteolysis (enzyme concentration 0.05% at 15°C, pH 7.4; mixing 30 min at 20 rpm) of bream mince improved mince susceptibility to freeze texturization. Formation of porous-fibrous texture of heat-set, freeze-texturized minces was associated with strong fragmentation of myosin heavy chain (MHC), decrease in extractability of myofibrillar protein and increased insoluble protein and thermal drip. Some deamidation of protein was also observed. We concluded that limited trypsin proteolysis accelerated transglutaminase mediated cross-linking of protein by acyl transfer reactions. Protein polymerization through plastein reactions and intermolecular hydrophobic interaction probably also occurred.