Effects Of Formulated Diet And Trash Fish Fatting Models On Flavour Of Chinese Mitten Crab (Eriocheir Sinensis)

This paper studies the effect of flavor on Chinese mitten crab(Eriocheir sinensis) fatted by formulated diet(FD) and trash fish(TF). There are tweleve samples include three parts, namely muscle, gonad and hepatopancrea. On the one hand, the non-volatile taste active compounds, including free amino acids, flavour 5,-nucleotides inorganic ions and betaine in tweleve samples were analyzed; on the other hand, volatile substances were determined by using MMSE-GC-MS method, also the main active volatile substances were confirmed combined with odor activity values. The purpose of this paper is to verify effect of flavor on Chinese mitten crab fatted by different two diets. We want to prove whether it is possible to replace trash fish with formulated diet. Furthermore, it should be theoretical basis for optimizing the crab feed. Test results are as follows:1. Umami intensity were significantly influenced by formulated diet in all three parts(except gonads of male). EUC value of Chinese mitten crab fatted by formulated diet were obviously higher than that of crab fatted by trash fish, which means the flavor of crab fatted by formulated diet can be comparable or even better than that fatted by trash fish. Additionally, EUC value of gonad of female is the highest.2. The content of flavor nucleotides(AMP, IMP, GMP, UMP) in crabs were significantly influenced because of formulated diet. The value were higher in FD crabs include all three parts, makes taste of FD crabs more delicious. Whereas content of PO43+ in TF crabs were higher than that in FD crabs. In addition, there is no significant difference between FD and TF crabs in content of free amino acids, other inorganic ions and betaine in all three parts. Finally, the nucleotide content of female gonad was highest with high TAV values of GMP, IMP and AMP greater than 1. That is the reason of highest EUC value of this sample.3. The amount of volatile substances investigated in FD crabs in muscle, gonad and hepatopancrea(except hepatopancrea of female) was higher than that in TF crabs, means formulated diet has effect on volatile substances of crabs.4. In all volatile substances, the centent of nitrogen—containings, sulfur— containings compounds investigated in FD crabs in all three parts was richer, means formulated diet has effect on content of volatile substances of crabs.5. A total of 34 volatile compounds were identified in muscle of female/male Chinese mitten crab fatted by FD and TF, 25, 18, 21 and 17 volatile compounds were quantified in female FD, male FD, female TF, male TF crabs. 10 aldehydes, 3 ketones, 7 alcohols, 5 nitrogen—containings, sulfur—Containings, 3 aromatic compounds were included in all volatile compounds respectively.A total of 55 volatile compounds include 18 aldehydes, 5 ketones, 7 alcohols, 3 aromatic compounds, 3 nitrogen—containings, sulfur—Containings, 3 furans were identified in gonad of female/male Chinese mitten crab fatted by FD and TF. 38, 46, 30 and 24 volatile compounds were quantified in female FD, male FD, female TF, male TF crabs respectively.A total of 83 volatile compounds include 35 aldehydes, 11 ketones, 9 alcohols, 3 aromatic compounds, 4 hydrocarbons,4 nitrogen—containings, sulfur—Containings, 8 furans were identified in hepatopancrea of female/male Chinese mitten crab. 71, 67, 75 and 66 volatile compounds were quantified in female FD, male FD, female TF, male TF crabs respectively.6. OAVs of four volatile compounds namely heptanal, octanal, nonanal, trimethylamine were calculated greater than 1, they consisted in muscle of crabs both fatted by FD and TF. Hexanal was only existed in muscle of FD crabs. Decanal and n-heptanol were detected in TF crabs merely.OAVs of octanal, 2,4-decadienal, trimethylamine, 2-ethylfuran, 2- amyl furan were calculated greater than 1, they consisted in gonad of FD and TF crabs.(E)-2- octene aldehyde, n-heptanol, 1-octen-3-ol were existed in gonad of FD crabs only.(E)-2-nonene aldehyde was detected in TF crabs merely.OAVs of 26 volatile compounds were greater than 1, they both consisted in hepatopancrea of FD and TF crabs. Caproic acid was existed in FD crabs only.7. In conclusion, flavor of crabs fatted by formulated diet were verified be well, it can be comparable or even better than that fatted by trash fish. So, formulated diet can be applied to the process of aquaculture. Of course, it is necessary that formulated diet should be improved and optimized, on the basis of this test, we suggest more inorganic ions added to it.