FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

Using K-value, a freshness index, at 20% as an acceptable limit of mackerelscad Decapterus russellii for sashimi quality together with sensory evaluation,the raw meat could be stored at -20 and -40℃ for 12 and 18 weeks, at 40, 30,20, 10, 5 and 0℃ for 3/4, 2, 4, 24, 48 and 96 hours, respectively. TheCa-ATPase activity of salt-soluble proteins increased with the storage time atthe early stage and then decreased rapidly during the prolonged storage. Itreached the maximum value in 1.5 h at 40 and 30℃, in 4 h at 20℃, in 2 days at10, 5 and 0℃, in 4 wk at -20℃, and in 6 wk at -40℃. For minimizing thedenaturation of muscle proteins during processing and storage, we supposed thatthe mackerel scad can be kept at below 10℃ during processing and stored at -20or -40℃ for less than 3 months. Based on the raw meat stored at varioustemperatures experiment, the Ca-ATPase activity was highly correlated with theintrinsic viscosity of salt-soluble proteins, while the solubility ofsalt-soluble proteins was negatively correlated with the K-value when stored atbelow 5℃.