Nippon Suisan Gakkaishi 79 (6), 1009-1016 (2013)

Comparison of discoloration of dark muscle between cultured yellowtail Seriola quinqueradiata and amberjack Seriola dumerili during chilled storage

KATSUJI MORIOKA,* KENJI OHNISHI AND YOSHIAKI ITOH

Faculty of Agriculture, Kochi University, Nankoku, Kochi 783-8502, Japan

This study was conducted to clarify the difference in discoloration profile of the dark muscle of cultured yellowtail Seriola quinqueradiata and amberjack Seriola dumerili during chilled storage. Discoloration of dark muscle was observed in yellowtail after storage for 24 h at 5℃, whereas no discoloration was observed in amberjack. The ratio of metmyoglobin (metMb) to total myoglobin (Mb) gradually increased in the dark muscle of both fish during storage, although it was higher in yellowtail than in amberjack. The pH of yellowtail dark muscle (pH 6.6) was lower than that of amberjack (pH 6.9). Similarly, the pH of yellowtail ordinary muscle (pH 6.0) was lower than that of amberjack (pH 6.1). Discoloration of the dark muscle of yellowtail initially appeared near the boundary between dark muscle and ordinary muscle. In crude Mb solutions prepared from the dark muscle of yellowtail and amberjack, the ratio of metMb to total Mb gradually increased during incubation at 25℃, and in both fish, this increase was accelerated by a decrease in pH from 7.0 to 6.0. These results indicate that a difference in the pH values of the dark and ordinary muscles of yellowtail and amberjack affects the difference in discoloration profile of dark muscle between these fish during chilled storage.


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