Analysis of nutritional and odor components in muscle of Siam alligator(Crocodylus siamensis)

Abstract

Crocodile is covered in treasure.Its leather has a high reputation in the world,and its armour contains a lot of bone collagen,protein,calcium,phosphorus and so on,and its gallbladder contains more than 20 kinds of bile acids and bilichols,which has a great medicine value.Its blood with antibacterial and antitumor activity is getting the attention of researchers both at home and abroad.There has been growing interest in commercial marketing of the crocodiles meat for human consumption in China,Thailand,America and Australia,which are all artificially breeding Siam alligator,Estuarine crocodile and Nile crocodile etc.Siam alligator is also called Siam freshwater crocodile,Singapore small crocodile,and is commonly known as Thai crocodile.It is getting more and more attention in China.With the increased amount of breeding,the deep processing for the meat of Siam alligator will be the focus of future research.Hence,our objectives were to identify the volatile components of Siam alligator muscle and evaluate its nutritional value.Odors in the muscle of Siam alligator were collected and determined by solid phase micro-extraction(SPME) and gas chromatography-mass spectrometry(GC-MS)before and after deodorization,and the nutritional components in the muscle of Siam alligator were analyzed by common methods.The result showed that there were 72kinds of volatile compounds detected,in which hexaldehyde was the main component of the odors,along with others constituted the peculiar smell of Siam alligator meat.The contents of moisture,protein,fat and ash in Siam alligator meat were 76.8%,19.8%,2.0% and 1.0% respectively.Sixteen types of amino acids in muscle were contained with accounting for 70.44% of the muscle dry matter content and including seven essential ones for human being.The constitutional rate of the essential amino acids was in accordance with the FAO(Food and Agriculture Organization)standard.According to the nutrition evaluation in amino acid score(AAS)and chemical score(CS),the essential amino acid index(EAAI)was 60.63%.The muscle also contained a variety amount of unsaturated fatty acids,in which the contents of eicosapentaenoic acid(EPA)and docosahexaenoic acid(DHA)were 1.44% and 2.96%,respectively.The Siam alligator meat also contained rich minerals and trace elements,especially the most calcium content.Consequently,the meat of Siam alligator is a kind of high-quality one with high protein and low fat,rich in a variety of unsaturated fatty acids and minerals.