Lipase and phospholipase activity in fish skeletal muscle and its relationship to protein denaturation

Canadian work has implicated production of free fatty acids (FFA) and/or phospholipid breakdown in the denaturation of fish muscle proteins during cold storage. A thorough study of the two phenomena in cod, lemon sole, halibut and dogfish indicates that there is no simple cause‐and‐effect. relationship. Lipolytic activity during cold storage at −7° and −14° has been studied in 11 other species. Phospholipase activity appeared to be negligible in the three Elasmobranchs studied, but, in all the other species, phospholipase was at least as important as lipase in producing FFA and in the Gadoids and related species almost all the FFA came from hydrolysis of phospholipids. Freezing and thawing of whole fish was found to lead to some FFA production.