Effects Of Different Cultivation Methods On Nutrition And Flavor Quality Of Female Swimming Crab(Portunus Trituberculatus)

Portunus trituberculatus have high nutritional value,delicious taste and unique flavor.So it is widely loved by consumers.Fishing is no longer able to meet the needs of consumers due to uncontrolled fishing and deteriorating environmental conditions.In recent years,aquaculture of portunus trituberculatus development is very rapid.Now,it is an important breed of aquaculture in China,and the aquaculture production increased year by year.The nutrition and flavor quality of portunus trituberculatus will be affected by the breeding environment and feeding technology.In this study,the changes of nutrition and flavor quality of gonad and crab meat of female portunus trituberculatus cultured in different breeding environments and different feeds were investigated.The nutritional quality of gonads and crab meat of female portunus trituberculatus cultured indoor and outdoor conditions were studied.There were no significant differences in the body weight,gonadal index,and meat yield of the female Portunus trituberculatus cultured indoor and outdoor conditions.The influence of indoor culture on the nutritional components of crab meat and gonad was relatively small.Both the gonads and crab meat of female portunus trituberculatus had higher PUFA.The n3/n6 of the gonads and crab meat of Indoor conditions were 3.68 and 2.75.The content of MUFA in the gonad of female portunus trituberculatus of indoor cultured was significantly lower than that of outdoor culture,but the content of PUFA was significantly higher than that of outdoor culture.The nutritive value of fatty acids of crab meat in outdoor culture was slightly better than that in indoor culture.The flavor quality of gonad and crab meat of female portunus trituberculatus cultured in indoor and outdoor were studied.The results of electronic nose,electronic tongue and sensory analysis showed that the quality of the gonad and the crab meat were slightly different under the condition of indoor and outdoor culture.For gonads,Indoor culture can significantly increase the contribution of AMP,glutamate,alanine,methionine,histidine and proline to gonadal taste.At the same time,the total content of amino acids and essential amino acids in gonad were significantly improved under the condition of indoor culture(p<0.05).The EUC value of gonad was 1.09 times higher than that of outdoor cultured.The content of aldehydes,ketones and furans in gonad was decreased by indoor culture,but alcohols,alkanes,nitrogen and sulfur and other types of content increased.The effect of AMP,methionine,lysine and histidine on the taste of crab meat was significantly enhanced by indoor culture.The total content of essential amino acids increased significantly,while the total content of free amino acids and the total content of amino acids were significantly reduced The EUC value of crab meat was 1.27 times higher than that of outdoor cultured.The relative percentage of aldehydes,ketones,aromatic compounds and furans decreased in indoor culture.The content of alcohols,alkanes,nitrogen and sulfur compounds and other compounds were increased.The effects of different water temperature cultured(heating water temperature treatment and normal water temperature treatment)on flavor quality of gonad and meat of female portunus trituberculatus were investigated.The results showed that the gonad and meat of crab cultured in different water temperature were distinguished effectively with electronic nose and electronic tongue.The contribution to gonads taste of GMP and AMP were improved by heating water temperature,as well as percentage of flavor amino acids and essential amino acids were increased,nevertheless the total free amino acid content was reduced.On the other hand,the content of GMP,IMP and AMP in meat of crab cultured in heating water temperature were increased 0.40,0.66 and 3.46 times,meanwhile content of flavor amino acids,essential amino acids and total free amino acids were enhanced significantly,and the EUC of crab meat in heating water temperature treatment was improved 0.59 times compared to normal water temperature treatment group(p<0.05).Then,the results of sensory evaluation showed that fatness and smell score of gonad of heating water temperature treatment group were obviously improved,sensory quality of crab meat were superior to normal water temperature treatment group.SPME-GC-MS analysis showed that the percentage of aldehydes,ketones,alcohols,alkanes and furan compounds in gonad of crab cultured in heating water temperature was increased.And the relative content of aldehydes,ketones,aromatic compounds,furans and other compounds was increased in this water temperature condition.In order to find the appropriate artificial diet to replace the trash fish,effects of replacement of trash fish with formulated diets and mixed diets on flavor quality of gonad and meat of female portunus trituberculatus were investigated.The result indicated that the content of GMP,IMP and AMP in the gonads of mixed diets treatment and formulated diets treatment were reached the level of trash fish treatment,nevertheless,the content of AMP in the crab meat of formulated diets treatment was significantly lower than that of trash fish treatment(p<0.05).There was no significant difference between the total amount of free amino acids in the gonad and crab meat of mixed diets treatment and trash fish treatment(p>0.05).and significantly higher than that of the formulated diets treatment.The electronic nose showed that the odor of the gonad and the crab meat would be changed with the artificial feed.The change in the odor of gonad is relatively large.The results of SPME-GC-MS analysis showed that the difference between the percentage of volatile substances in crab meat and gonad of mixed diets treatment and trash fish treatment is relatively small.Compared with the other two groups,there was a decrease in the percentage of aldehydes,alcohols and furans in crab meat and gonad,while the content of alkane hydrocarbon increased.