草鱼肌肉脂肪酸组成及其在冷藏中的含量变化

Changes in Fatty Acid Composition during Cold Storage of Fresh Grass Carp Muscle

采用气相色谱-质谱法研究草鱼肌肉脂肪酸组成及其在2～4℃冷藏条件下的变化。结果表明,草鱼肌肉脂肪中不饱和脂肪酸含量较高;饱和脂肪酸(SFA):单不饱和脂肪酸(MLFA):多不饱和脂肪酸(PUFA)的比值为1.08:2.19:1,ω-6/ω-3 PLFA的比值为5.65:1,符合中国营养学会推荐的脂肪酸摄入标准;冷藏过程中,草鱼肌肉总脂肪含量逐渐下降,MUFA和PUFA的相对含量逐渐减少,SFA的相对含量逐渐增多,脂肪酸的降解速率及程度与脂肪酸的不饱和程度呈正相关;脂肪酸的降解与其结构类型有关,ω-3型PUFA降解比ω-6型PUFA更早,但ω-6型PLFA的降解速率更快;部分长链多不饱和脂肪酸(LPUFA)随冷藏时间的延长相对含量略微增加。因此,控制草鱼肌肉脂肪酸在冷藏过程中的降解有利于维持鱼肉制品的营养价值,延长其货架期。

The fatty acid composition of fresh grass carp muscle and its changes during cold storage at 2-4 ℃were analyzed by GC-MS. Fresh grass carp muscle was found to be rich in unsaturated fatty acids and its ratio of short chain fatty acids （SFA） to mono-unsaturated fatty acids （MUFA） to poly-unsaturated fatty acids （PUFA） and ratio of 09-6 PUFA to w-3 PUFA were 1.08：2.19：1 and 5.65：1, respectively, meeting the fatty acid intake requirements recommended by Chinese Nutrition Society. Total fatty acid content of grass carp muscle and the relative contents of MUFAs and PUFAs gradually declined during cold storage, whereas relative SFA content gradually increased. In addition, there was a positive correlation between the rate and extent of fatty acid degradation and their extent of unsaturation. The degradation of fatty acids in grass carp muscle was associated with their structures, ω--3 PUFAs were degraded earlier but more slowly than ω-6 PUFAs. The relative contents of some long chain unsaturated fatty acids （LPUFA） slightly increased with increasing storage time. These results indicate that the nutritive value of fish products can be maintained and their shelf life can be prolonged by suppressing the degradation of fatty acids in grass carp muscle during cold storage.