Acceleration of lipid oxidation in the skin of fish by the disintegration of connective tissue.

As one of the causes for which lipid oxidation proceeded preferentially in the skin during cold storage of fish in the round, it was supposed that lipids in the skin, buried in the connective tissue of skin, move to the surface from the inner layer by the disintegration of connective tissue and that the fact brings about acceleration of lipid oxidation during storage of fish. The acceleration of lipied oxidation was examined by the degradation of connective tissue in the skin with glycosidase and proteinase. By the incubation of the skin of Pacific mackerel with hyaluroniodase at 37°C for 2 h or with Pronase P at 37°C for 2 h after the preincubation at 70°C for 10 min, the value of TBA/kg skin increased with reference to control. After the incubation of the skins of four kinds of fish (Pacific mackerel, sardine, striped pigfish and plaice)with both enzymes, acceleration of liped oxidation was observed in every skin. Increasing rates of lipid oxidation in all the skins were almost the same with hyaluronidase and Pronase P. Among these fishes; increasing rate was the hightest in the skin of plaice, which was the lowest in lipid content.