Study On Flavor Compounds Of Chinese Mitten Crab

The non nitrogen compounds, nitrogen compounds and volatile flavor compounds of Chinese mitten crab were systematically studied in this paper. The flavor differences up on different parts of Chinese mitten crab under different breeding conditions were compared.The non nitrogen compounds were firstly studied. The contents of lactic acid, glucose and inorganic ions in periopods muscle, body muscle and ointment of Chinese mitten crab from Yangcheng Lake and pond were carried out by using spectrophotometer. The results showed that to different parts of Chinese mitten crab under the same breeding conditions, the content of lactic acid in periopods muscle of Chinese mitten crab from Yangcheng Lake was 3.54 mg/g; the content of glucose in ointment was 1.41 mg/g; the content of K+ and Cl- was 3.15 mg/g and 6.01 mg/g respectively in periopods muscle, and the content of Ca2+ was 0.99 mg/g in body muscle, besides, the content of Na+, Mg2+ and PO43- in ointment of Chinese mitten crab from Yangcheng Lake was 3.58 mg/g, 0.38 mg/g and 1.80 mg/g respectively, all of which were higher than other two parts of Chinese mitten crab from Yangcheng Lake. The content of lactic acid in periopods muscle of Chinese mitten crab from pond was 4.55 mg/g, which was three times higher of its other two parts; the content of glucose in body muscle was 2.00 mg/g, which was remarkably higher than other two parts; the content of Na+ and Mg2+ was 1.95 mg/g and 0.25 mg/g respectively in periopods muscle, the content of K+ and Ca2+ was 2.88 mg/g and 0.81 mg/g respectively in body muscle, and the content of Cl- and PO43- was 3.74 mg/g and 1.28 mg/g respectively in ointment, all of which were higher than other two parts of Chinese mitten crab from pond. To the same parts of Chinese mitten crab under different breeding conditions, only the content of lactic acid in body muscle of Chinese mitten crab from pond was lower than which in body muscle of Chinese mitten crab from Yangcheng Lake; from glucose, only the content of glucose in body muscle of Chinese mitten crab from Yangcheng Lake was remarkably lower than which in body muscle of Chinese mitten crab from pond; to Chinese mitten crab from Yangcheng Lake, only the content of Na+ in periopods muscle was lower than which in periopods muscle of Chinese mitten crab from pond, and only the content of K+ in body muscle was lower than which in body muscle of Chinese mitten crab from pond, and only the content of Ca2+ and Cl- in ointment was lower than which in ointment of Chinese mitten crab from pond.Nitrogen compounds, including free amino acids, nucleotide and glycine betaine were researched. The results showed that the total content of free amino acids in periopods muscle, body muscle and ointment of Chinese mitten crab from Yangcheng Lake was 19.32 mg/g, 15.89 mg/g and 20.88 mg/g, and the total content of flavor amino acids was 11.25 mg/g, 9.75 mg/g and 11.93 mg/g; the total content of free amino acids in periopods muscle, body muscle and ointment of Chinese mitten crab in pond was 13.26 mg/g, 14.61 mg/g and 6.15 mg/g, and the total content of flavor amino acids was 8.45 mg/g, 8.91 mg/g and 3.16 mg/g. The content of nucleotide and glycine betaine in different parts of Chinese mitten crab under different breeding conditions was different. The content of AMP was 92.53μg/g in body muscle of Chinese mitten crab from Yangcheng Lake, the content of IMP was 83.71μg/g in ointment of Chinese mitten crab from pond, the content of GMP was 74.91μg/g in periopods muscle of Chinese mitten crab from pond, all of which were the highest too. The content of glycine betaine in body muscle of Chinese mitten crab from Yangcheng Lake was 4.04 mg/g, which was highest.Volatile compounds in Chinese mitten crab from Yangcheng Lake and pond were analysised by headspace solid phase microextraction(HS-SPME) combined GC-MS. First the volatile compounds of periopods muscle, body muscle and ointment mixed were determined. A total of 45 compounds were identified, including 10 hydrocarbon compounds, 16 alcohols, 4 aldehydes, 3 ketones, 1 acids, 2 esters, 1 phenols, 7 nitrogen or sulphur compounds, 1 furan compounds. Then the volatile compounds of periopods muscle, body muscle and ointment were respectively determined. A total of 77 compounds were identified, including 13 hydrocarbon compounds, 30 alcohols, 4 aldehydes, 9 ketones, 11 acids, 4 esters, 1 phenols, 4 nitrogen or sulphur compounds, 1 furan compounds.