Masamichi Toyomizu

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.

Studies on the Antibiotic Action of Fish Components-VIII

In order to ascertain the mechanism in producing the antibiotic action of the caramary oil by the addition of salts, the concentration of CuSO4, FeCl3, Co(NO3)2 and KMnO4 required, has been discussed from the viewpoint of oxidation-reduction potential of the media. On low rH media which contain reducing suger and KH2PO4, -standard medium (Peptone-Hayduck medium: glucose 50g., peptone 10g., MgSO4•7H2O 3g., KH2PO4 1g., agar 20g. and distilled water 1l.), standard medium without MgSO4 and fructose medium with KH2PO4-the concentration of these salts required was high, and Co (NO3)2 was not effective. On the contrary on high rH media, -standard and fructose media without KH2PO4 and sucrose media with or without KH2PO4 which contained more or less peptone, -the concentration of them was small and Co(NO3)2 was also effective. Therefore, it could be assumed that the decrease of oxidizability of the medium would need high concentration of these salts. In these cases, the precipitation caused by the combination of CuSO4 or FeCl3 with peptone and KH2PO4 reduced the inhibitory action by these salts alone (without the addition of the calamary oil), but had no influence on the antibiotic action of the calamary oil by adding salts.