3种金枪鱼头不同部位成分比较及营养学评价

分析黄鳍金枪鱼、大眼金枪鱼和马苏金枪鱼鱼头不同部位（鱼肉、鱼皮和鱼骨）的基本营养成分，并评价其营养价值。结果表明：3 种金枪鱼鱼头均含有丰富的粗蛋白、粗脂肪和灰分；3 种金枪鱼鱼头的鱼肉中必需氨基酸种类齐全，必需氨基酸与总氨基酸含量的比值接近40%，氨基酸评分较高，必需氨基酸指数大于86，属于优质蛋白；而鱼皮和鱼骨中蛋白质的营养价值相对较低；3 种金枪鱼鱼头的脂质中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸的比例接近于1∶1∶1，富含二十二碳六烯酸（docosahexaenoic acid，DHA）和二十碳五烯酸（eicosapentaenoic acid，EPA），其含量分别为15.69%～23.29%和4.02%～5.15%，DHA与EPA的比值为3.23～5.27，n-6与n-3多不饱和脂肪酸的比值为0.13～0.29，具有较高的营养价值；3 种金枪鱼鱼头中还富含对人体健康有益的Ca、Fe、Zn等矿物质元素。

Comparative Composition and Nutritional Evaluation of Different Head Parts of Three Tuna Species

The basic nutrients of different parts (muscle, skin and bone) of yellow fin tuna, big eye tuna and southern bluefin tuna heads were analyzed and their nutritional value was evaluated. The results showed that the heads of all three tuna species was rich in crude protein, crude fat and ash. For all species, head muscle contained a full range of essential amino acids, the ratio of essential amino acids to total amino acids was close to 40%, the amino acid score was higher, and the essential amino acid index value was greater than 86, indicating that tuna head muscle is a high-quality source of protein. In contrast, the protein nutritional value of tuna head skin and bone was relatively lower. The ratio of saturated to monounsaturated to polyunsaturated fatty acids in head lipids from the three tuna species was close to 1:1:1, which were rich in docosahexaenoic acid (DHA, 15.69%–23.29%) and eicosapentaenoic acid (EPA, 4.02%–5.15%). The ratio of DHA to EPA was 3.23–5.27, and the ratio of n-6 to n-3 polyunsaturated fatty acids was 0.13–0.29, suggesting high nutritional value. Furthermore, the tuna heads were rich in mineral elements such as Ca, Fe and Zn, which are beneficial to human health.