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

Abstract

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.