1National Research Institute of Fisheries Science, Yokohama, Kanagawa 236-8648, 2Nagoya Bunri University, Nagoya, Aichi 451-0077, 3Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan
The mantle muscles from instantly killed and frozen then thawed specimens of the common squid Tedarodes pacificus were boiled at 80°C for 20 min, freeze-dried, and ground into powder, which were named “the dried, seasoned and shredded products (“sakiika” in Japanese) browning models”. The models were measured for the contents of ATP and related compounds and reducing sugars such as ribose, glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P) during preservation at 35°C for 30 days where the progression of browning was most likely caused by the Maillard reaction.
While the hypoxanthine content of the live squid was much lower than that in the frozen one, the content of ribose in the model from the live squid was also much lower than that from the frozen one before preservation. During preservation at 35°C, the browning of the model from the frozen squid proceeded rapidly, whereas that from the live squid proceeded slowly. Concomitantly, the contents of ribose in the model from the frozen squid decreased rapidly, in contrast to the contents of G6P and F6P which decreased much slower. However, the contents of ribose and G6P in the model from the live squid were only slightly decreased.
The b* value of color difference measured as a parameter of browning showed a high coefficient in the linear regression against the decrease of ribose (R2=0.724) for the model from the frozen squid, but not for that from the live squid with very low content of ribose. On the other hand, the coefficient of the b* value against the decrease of G6P was very low for the model from the live squid