The changes in chemical composition and nutritive value of squid and cod, low in fat content and consumed predominantly in Japan, were determined after frozen storage.
In squid stored at -20°C for 18 months, the protein denaturation (the decrease of the protein solubility) and the hydrolysis of lipid (the increase of free fatty acid) were not observed, whereas TBA value increased. In cod frozen -20°C for 11 months, the rapid protein denaturation and the hydrolysis of lipid were observed. On the other hand, no distinct change occurred in TBA value of cod muscle.
These marine foods after frozen storage were freeze-dryed and administered to weanling rats as the sole protein source. Squid stored for 9 months was compared with it of 18 months and cod stored for 1 month was compared with them of 7 and 11 months. Growth curves, growth indices, such as body weight gain ratio, food consumption and food conversion, and protein metabolism indices, such as digestibility and retention, were not significantly different between a short term storage and a long term storage.

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