Studies on the Food Components of Tilapia Oreochromis niloticus Cultured in Seawater 2. Comparison of Lipid Components of Tilapia with Freshwater Cultured Tilapia

해수사육 틸라피아 근육의 식품성분 연구 2. 담수 및 해수사육한 틸라피아 근육의 지질성분

The composition of muscle lipids and their fatty acid composition of two groups of tilapia, cultured in fresh and seawaters, were investigated. The total lipid(TL) of seawater culture group is a little richer than that of freshwater culture. The neutral lipid(NL) is the most abundant in muscle lipids of two groups, followed by the phospholipid(PL) and glycolipid (GL). The increment of TL content seemed to depend upon triglyceride(TG) fraction, because large portions of lipids are consisted of TG. Phosphatidyl choline(PC), phosphatidyl ethanolamine and sphingomyelin were identified in PL, and the content of PC was the highest. The principal fatty acids of muscle lipids were 14 : 0, 16 : 0 and 18 : 0 as for saturated fatty acids, and 16 : 1, 18 : 1, 18 : 2 and 22 : 6 as for unsaturated fatty acids. In particular, high contents of 16 : 0 and 18 : 1 were observed in TL, NL and GL. However, low contents of 18 : 1 and 18 : 2 were observed in PL, while they were high in polyunsaturated fatty acids with 20 : 4, 20 : 5 and 22 : 6. In the meantime, no significant difference was observed in the composition of muscle lipids and their fatty acids between two groups cultured in seawater and freshwater.

해수사육한 틸라피아와 담수사육한 것의 근육지질의 구성 및 그 지방산조성을 분석$\cdot$비교하였다. 해수사육군은 담수사육군에 비해 총지질함량이 미미하지만 약간 많았고, 중성지질이 구성지질의 대부분을 이루고 있으며, 다음으로 인지질, 당지질의 순이었다. 중성지질 중에는 triglyceride(TG)의 조성이 가장 많았으며, 총지질 함량의 증가는 TG획분의 증가 때문으로 생각되었다. 한편 인지질에서는 phosphatidyl chloine, phosphatidyl ethanolamine, sphingomyelin이 동정되었으나, phosphatidyl choline이 가장 높은 조성비를 보였다. 각 구성지질을 이루는 주요지방산은 14 : 0, 16 : 0, 18:0 등의 포화산을 비롯하여 16. 1, 18 : 1, 18 : 2, 22:6 등의 불포화산이었으며, 특히 16 : 0과 18 : 1의 구성비가 총지질, 중성지질, 당지질에서 높았으나, 인지질에서는 18 : 1, 18 : 2의 조성비가 적고 20 : 4, 20 : 5, 22 : 6등의 고도불포화지방산이 많았다. 그러나 이러한 특징은 해수시료군에서나 담수시료군에서나 마찬가지였으며, 두 시료군간에 차이는 확인할 수 없었다.