| Chinese mitten crab (Eriocheir sinensis) is a traditional savory food in China with delicious taste and unique pleasant aroma. In this paper, flavor of the crab was analyzed and the freezing technology was obtained.Chinese mitten crab was analyzed for proximate composition, minerals, amino acids and fatty acid composition, and also evaluated for the nutritional quality. The yields of crab meat and edible viscera were 24.2% and 9.2% respectively. The crab meat contained 18.9% crude protein. About 80% of the protein lied in crab meat portion, while about 90% of fat lied in viscera. Chinese mitten crab was an excellent source of minerals, particularly zinc, iron, copper and phosphorous. The crab protein contained high amounts of glutamic acid (151 mg/g), aspartic acid (99 mg/g), arginine (99 mg/g), lysine (81 mg/g) and leucine (77 mg/g); and it was a high quality protein with well-balanced essential amino acid compositions. Twenty six fatty acids were found in crab oil. The monounsaturated fatty acids were dominating with a percentage of 49.81. Oleic acid (18:1) was the dominant fatty acid, followed by palmitoleic acid (16:1), palmitic acid (16:0) and linoleic acid (18:2n-6); and the percentages were 30.96, 14.32, 14.22 and 11.91 respectively. The ratio of n-6/n-3 polyunsaturated fatty acids (PUFAs) values was 2.2; and it's an n-3 PUFAs rich food in usual diet. In short, the results showed that Chinese mitten crab must be a nutritious food.The non-volatile taste active compounds, including soluble sugars, succinic acid, free amino acids and flavour 5'-nucleotides in the meat of Chinese mitten crab were analyzed, and their taste impacts were evaluated by taste active values (TAVs) and equivalent umami concentration (EUC) methods in this study. The total free amino acid content of crab meat was 20.85 mg/g. Arginine, glycine and alanine were the major free amino acids, accounting for more than 70% of the total free amino acids. 5'-Adenosine monophosphate (AMP) was the main flavour 5'-nucleotide (75.3 mg/100g), followed by 5'-inosine monophosphate (IMP) (34.4 mg/100g) and 5'-guanosine monophosphate (GMP) (2.3 mg/100g). Arginine, glycine, alanine, glutamic acid, IMP and AMP were of high TAV greater than one, and they had strong taste impacts on the crab meat flavour. Glycine and alanine contributed to the major sweet taste, while glutamic acid, IMP and AMP contributed to the strong umami taste. As the TAVs of soluble sugar, succinic acid and bitter free amino acids were lower than one, those compounds are likely to have insignificant impact on the taste of the crab meat. The EUC was 4.2 g MSG/100 g crab meat, which meant that the umami taste of the crab meat was very intense.Volatile compounds in Chinese mitten crab (whole crab and crab meat) were investigated. Samples were extracted by simultaneous distillation-extraction (SDE) and then analyzed by Gas Chromatography-Mass Spectrometry (GC-MS). A total of 94 volatile compounds were identified and quantified in this study. 86 and 83 compounds were found in whole crab and crab meat, respectively. 76 compounds were found in both, including the 5-9 carbons aldehydes, methyl ketones, 2,3-butadione, 1-octen-3-ol, amines, pyrazines, thialdine and thiazoline, etc. In general, the concentrations of volatile compounds in whole crab were considerably greater than in crab meat, and SDE-GC-MS could be used to extract, separate and identify the volatile compounds in this study.The aroma of crabmeat and edible viscera was analyzed by flavor profile analysis methods. The aroma of crabmeat can be described as an intensive meaty, accompanied by mild sweet, green and fishy attribution, and a very little mud, amino and oily attribution, without roast, acid and rancid note; while the aroma of edible viscera can be described as an intensive fishy and oily note, accompanied by mild sweet, green and mud note, and a very little meaty and amino note, without roast, acid and rancid note.The key odor-active compounds were analyzed by HS-SPME-GC-MC combined with GC-O method. In crabmeat, the'fishy, crabmeat','sweet, green, egg'and'potato'notes were intensive, and'sulfur','roast, sweet'and'green'notes were mild, and'meaty','amine','green','mud'and'fishy'notes were insignificant. The key odor-active compounds were trimethylamine, dimethyl sulfide, 3-(methylthio)-propanal, 1-octen-3-one, dimethyl trisulfide, 1-octen-3-ol, benzaldehyde and 2-acetyl-thiazole.The changes of flavor, texture and fatty acid were analyzed in crab during frozen storage. Using different treatment methods (triphosphate, citric acid and TBHQ) and frozen methods (slow frozen, force-aired frozen and liquid nitrogen frozen), the high quality frozen crab technology was obtained: using liquid nitrogen frozen method to maintain texture: Crack was formed in crabmeat, which reduce texture aging during frozen storage. Using citric acid combined with TBHQ treatment to maintain the sensory attribute, the total volatile base nitrogen was reduced and oxidation was depressed. The best storage temperature should below -45℃according to the obtained glass transition temperature.
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