天然鱼翅翅针中氨基酸和脂肪酸组成分析与评价

为客观评价天然鱼翅的营养价值,为消费者做出指导,分析和评价了天然鱼翅的关键食用部位——翅针中的氨基酸和脂肪酸组成。氨基酸测定结果显示:镰状真鲨和大青鲨鱼翅翅针中共检出16种氨基酸,种类齐全,其中包含7种必需氨基酸(EAA);其氨基酸总量(TAA)分别为24.76%和23.32%,高于常见经济鱼类肌肉中TAA含量,但其EAA含量远低于常见经济鱼类肌肉中EAA含量,均为4.44%。氨基酸评分(AAS)结果显示:两种翅针除苯丙氨酸+酪氨酸的AAS评分是FAO/WHO评分标准的1.10和1.25倍之外,其余氨基酸的AAS评分均介于0.3~0.6之间,远低于评分标准;亮氨酸为两种翅针的第一限制性氨基酸。化学评分(CS)结果显示:两种翅针的CS评分均介于0.1~0.5之间,远低于标准蛋白(全鸡蛋蛋白)营养价值,亮氨酸或蛋氨酸+胱氨酸为第一限制性氨基酸;必需氨基酸指数(EAAI)评分结果显示:两种翅针的EAAI评分与标准蛋白(全鸡蛋蛋白)相距甚远,且低于几种常见经济鱼类肌肉的EAAI值。综合AAS、CS和EAAI分析结果认为:镰状真鲨和大青鲨翅针的氨基酸营养价值偏低,非优质蛋白质源,其主要限制性氨基酸为亮氨酸和蛋氨酸+胱氨酸。脂肪酸测定结果显示:两种天然鱼翅翅针中共检出4种饱和脂肪酸(SFA)、5种单不饱和脂肪酸(MUFA)和7种多不饱和脂肪酸(PUFA);其不饱和脂肪酸的含量(MUFA+PUFA)高于饱和脂肪酸(SFA)的含量,且富含花生四烯酸(ARA,分别为9.8%和9.2%)和二十二碳六烯酸(DHA,分别为4.2%和5.9%);两种天然翅针的ΣPUFA(n-3)/ΣPUFA(n-6)比值均明显高于FAO/WHO推荐比值(0.1~0.2),说明两种天然鱼翅翅针的脂肪酸营养价值较高。结论:镰状真鲨与大青鲨鱼翅翅针中氨基酸营养价值偏低,并非优质蛋白质来源;但富含人体必需的不饱和脂肪酸,其脂肪酸营养价值较高。

Composition Analysis and Evaluation of Amino Acids and Fatty Acids in Natural Shark Fin Cartilage

In order to objectively evaluate the nutritional value of natural shark fins and give guidance to consumers,the composition of amino acids and fatty acids of shark fin cartilage which was the key edible parts of shark fin was analyzed and evaluated. The determination of amino acid showed that,16 species of amino acids were detected in the two shark fin cartilage respectively from Carcharhinus falciformis and Prionace glauca,including seven essential amino acids(EAA). The total amount of amino acids(TAA)of the two shark fin cartilages was 24.76% and 23.34%,respectively,higher than that in the muscle of some common economic fish,but the content of EAA both were 4.44%,was significantly lower than that in the muscle of common economic fish. Amino acid score(AAS)results showed that except the score of phenylalanine+tyrosine of the two shark fin cartilages was 1.10 and 1.25 times higher than the standard of FAO/WHO respectively,the AAS scores of other amino acids were all between 0.3~0.6,which were far lower than the scoring criteria. According to the AAS results,leucine was the first limiting amino acid of two kinds of fin cartilages. Chemical score(CS)results showed that the CS scores of the two fin cartilages were between 0.1~0.5,which were far below than the standard protein(whole egg protein),leucine or methionine+cystine were the first limiting amino acid. The results of the essential amino acid index(EAAI)showed that,the EAAI scores of the two fin cartilages were far from the standard protein(whole egg protein)and lower than that of several common economic fish muscles. In summary,the AAS,CS and EAAI analysis results showed that the amino acids nutritional value of the two shark fin cartilages from the Carcharhinus falciformis and Prionace glauca were low and not high quality protein source,their main limiting amino acids were leucine and methionine and cysteine. The determination of fatty acids showed that four saturated fatty acid(SFA),five monounsaturated fatty acids(MUFA)and seven polyunsaturated fatty acids(PUFA)were detected in the two natural shark fin cartilages. The content of unsaturated fatty acids(sum of MUFA and PUFA)was higher than that of SFA,and in which there was abundant arachidonic acid(ARA,which was 9.8% and 9.2% respectively)and docosahexaenoic acid(DHA,which was 4.2% and 5.9%respectively). The ratio of ΣPUFA(n-3)/ΣPUFA(n-6)in the two shark fin cartilages were both significantly higher than the recommended ratio of FAO/WHO(0.1~0.2),which indicated that the fatty acids of the two natural shark fin cartilages had higher nutritional value. Conclusion:It was naturally low in the amino acid nutritional value of the two shark fin cartilages which were not the source of high quality protein,but they were rich in the essential unsaturated fatty acids which meant that the two shark fin cartilages both had high nutritional value in the fatty acids.