Polyamines as potential indexes for freshness of fish and squid

Changes in putrescine (Put), cadaverine (Cad), tyramine (Tym), tryptamine (Tpm) and histamine were examined in the meats of sardine and saury pike during storage at 5*C and 20°C. The levels of Put, Cad, Tym and Tpm in the meats of these fishes increased as decomposition progressed regardless of storage temperature. Of these four polyamines, a maximum formation was observed for Cad, which seemed to be the most useful index for freshness of fish; below 15 mg/100g at the acceptable stage, between 15 and 20 mg/100g at the stage of initial decomposition, and over 20 mg/100g at the stage of advanced decomposition. The concentrations of Put, Cad, Tym, Tpm and agmatine (Agm) were determined in common squid muscle during storage at 0°C, 3.5°C and 15°C. Agm appeared to be most useful as a potential index for freshness of common squid. Agm was detected in small amounts even in the fresh muscle, and the concentration increased with storage time, exceeding 30 mg/100g at initial decomposition and reached the level of 40 mg/100g at advanced decomposition. Put was detected in small amounts (less than 1 mg/ 100g) at initial decomposition and increased rapidly at advanced decomposition. This amine might be invoved in the putrid smell.