Relation between protein denaturation and lipid oxidation in fish [sardine, Sardinops melanostictus] muscle during storage at low temperatures

We have reported previously that the rate of lipid oxidation due to POV (peroxide value) decreases with temperature and increases with lipid content in fish muscle. In the present paper, we investigated the relation between myofibrillar-protein (Mf-P) denaturation and lipid oxidation in muscles of sardine under various conditions during storage at low temperatures (0, -5, and -20°C). The Mf-P denaturation in sardine muscle was determined by measuring Mf (Ca)-ATPase activity as an indicator; it occurred rapidly at an early stage where lipid oxidation was still in the induced period during storage. The rate of denaturation was independent of lipid content in the fish muscle. As a result, the relation between protein denaturation and lipid deterioration in fish muscle stored at low temperature was not recognized at an early stage of storage. Both phenomena appeared to occur independently.