養殖ハマチの成長にともなう一般成分と無機成分の季節的変動

Abstract

The seasonal variations with growth in the proximate compositions and mineral contents of cultured yellowtail, Seriola quinqueradiata, were examined during a 20 month period from Febru-ary, 1985 to November, 1986. The muscle of yellowtail was divided into four parts: dorsal, ventral, caudal, and dark muscles, and for each part the amounts of moisture, crude protein, crude lipid, ash, and 13 kinds of minerals were analyzed. The following results were obtained. The moisture content was higher in the caudal muscle than in the other parts. In all the muscles moisture contents tended to increase in the summer. Crude protein contents were slightly higher in one year old fish than those in two years old. In lipid contents, there was a remarkable variation according to growth, and the lowest level was found in the summer. A negative correlation was noticed (n=160, r=-0.692) between the contents of moisture and crude lipid. The seasonal variations in ash content in the dorsal, ventral, caudal muscles were relatively slight.Seasonal variations of Ca, Na, and K contents in the muscles were significant; values of P, Fe, K, Mg, Cu, and Mn in dark muscle were different considerably from those in other parts. Higher contents of Fe, Cu, and Mn were noticed in the dark muscle. Heavy metals such as Pb, Hg, and Cd in all the muscles tested were within the dietary safety levels. The mean value of the edible portion of all samples assayed during a 20 month period was as follows: moisture 55.3g, crude protein 23.6g, crude lipid 14.0g, ash 1.8g, Ca 3mg, P 265mg, Fe 1.1mg, Na 26mg, and K 336mg per 100g. These results indicate that several components differ in value from those listed in the standard tables of food composition in Japan.