Correlation of gut microorganisms and non-volatile flavor substances provides new insights for breeding Scylla paramamosain

The farming of Scylla paramamosain with specific flavors has a higher commercial value,and the flavors are related to the integrated farming environment and non-volatile flavor substances,while the survival environment is one of the important ways to source gut microorganisms in the organism.In this study,the levels of dominant taxa in the gut flora of S.paramamosain from Mong Cai,Vietnam(VN),Taishan City,Guangdong Province(TS)of China,and Ninghai County,Ningbo City(NB)Zhejiang Province of China converged with those of S.paramamosain from Sanmen County,Ningbo City(CK 1,CK 2,and CK 3)at 28 d of domestication.The top 15 genera with the highest abundance of VN,TS,and NB gut flora were the same as CK 1,CK 2,and CK 3,but with different percentages,and gradually converged to CK 1,CK 2,and CK 3,respectively,at 28 d of domestication.Correlation between intestinal flora and non-volatile flavor substances in the hepatopancreas at the percentage level of relative abundance of bacterial genera found that above 28 d of domestication,Muribaculaceae,Psychrilyobacter,Clostridia_vadinBB 60_group,Halarcobacter Carboxylicivirga,Sediminispirochaeta may be the most important genera affecting flavor amino acids of VN.Sediminispirochaeta,Carboxylicivirga,Halarcobacter,Photobacterium,ZOR 0006,Psychrilyobacter,and Pseudomonas may be the most important genera affecting flavor amino acids of NB.Sediminispirochaeta,Carboxylicivirga,Halarcobacter,Photobacterium,ZOR 0006,Vibrio,and Sphingomonas may be the most important genera affecting flavor amino acids of TS.These results show that the intestinal flora structure of crabs from different areas were domesticated in the same area for at least 28 d before they converged to that of the domesticated crab,and the most important genera affecting the flavor amino acids of TS,VN,and NB were also identified.The results of this study provide a reference and basis for the technique of directional cultivation of the flavor quality of the crab.

Comparison of Flavor Substances in Dried Shrimp Products Processed by Litopenaeus Vannamei from Two Aquaculture Patterns

Dried shrimp is a popular aquatic food worldwide due to its unique flavor.However,its flavor qualities on the market remain uneven.This study aimed to compare flavor substances in dried shrimp processed by Litopenaeus vannamei from two aquaculture patterns(earthen pond and greenhouse)using amino acid automatic analyzer,high-performance liquid chromatography(HPLC),gas chromatography(GC)-ion mobility spectrometry(IMS),and GC-mass spectrometry(GC-MS).The results revealed that dried shrimp from earthen pond had significantly higher free amino acids and 5’-nucleotides than those from greenhouse(P<0.05),and their corresponding equivalent umami concentrations(EUCs)were 23.45 g MSG(100 g)^(−1)and 14.86 g MSG(100 g)^(−1),respectively.For volatile compounds,GC-IMS analysis indicated significant differences in volatile compounds between dried shrimp from different aquaculture patterns.According to the quantitative analysis of GC-MS,11 volatile compounds were identified as aroma-active compounds(AACs),of which six AACs(1-octen-3-ol,3-methylbutanal,nonanal,trimethylamine,2,5-dimethylpyrazine,and 2,3,5-trimethylpyrazine)were found in all dried shrimp samples.Although dried shrimp from greenhouse possesses higher OAVs,OAVs of(E,E)-2,4-nonadienal(fishy smell),and 3,5-diethyl-2-methylpyrazine(burnt smell)reached 171.2 and 333 respectively,imparting negative effects on flavor.In general,dried shrimp from earthen pond had a better flavor profile than those from greenhouse.

Influence of stir-frying on the lipid stability and flavor substances in oat flour during storage using HS-SPME-GC-MS and electronic nose

Objectives:We used stir-fried oat flour as experimental material and raw oat flour as a control to explore the influence of stir-frying on the storagequalityofoatflour.Materials and Methods:The HS-SPME-GC-MS method combined with electronic nose technology was used to understand the lipid stability and analyze the changes in the flavor of the substances during the entire storage period.Results:It was observed that during the storage period,stir-fried oat flour contained less water than raw oat flavor.The former was characterized by a lower fatty acid value,lower acid value,and lower linoleic acid content,but higher oleic acid content and palmitic acid content compared to the latter.With the passage of storage time,the palmitic acid content significantly increased,and the linoleic acid content significantly decreased in raw and stir-fried oats flour(P<o.05).The sulfur and methyl contents in the stir-fried oat flour were higher than those in the raw flour,while nitrogen oxide content in the former was lower than that in the latter.Stir-fried oat flour possessed a total of 78 identified flavor substances.The process of stir-frying boosts the oxidation decomposition of unsaturated fatty acids aldehydes and heterocyclic compounds produced by the Maillard reaction,so the flavor substances of stir-fried oat flour are richer.Conclusions:Stir-fried oat flour,containing diverse types of flavor substances,experienced more obvious flavor changes throughout the storage period than raw oat flour.

Changes and correlation of microorganism and flavor substances during persimmon vinegar fermentation

To investigate the microbial diversity and the change of the flavor substances during the traditional natural persimmon vinegar fermentation,two group samples from alcohol fermentation stage(A)and acetic acid fermentation stage(B)were analyzed.The results showed that Burkholderia,Lactobacillus,Acetobacter,Komagataeibacter were the main bacteria,and the major fungi were Saccharomyces,Hanseniaspora,Hortaea,and Cladosporium at the genus level.The contents of flavonoids and polyphenols in B increased by 17.91%and 26.59%compared with A,respectively.The superoxide anion scavenging activity significantly increased by 20.15%.The contents of total free amino acids were 5709.99±410.36 mg/L and 5736.16±472.02 mg/L,and the total contents of 9 organic acids were 19.89±1.20 g/L and 33.77±2.49 g/L in samples A and B,respectively.Pearson correlation analysis showed that 11 flavor compounds were related to Lactobacillus and Leuconostoc;8 and 10 compounds were respectively related to Komagataeibacter and Acetobacter;13 and 19 flavor compounds were respectively associated with Saccharomyces and Monascus.Orthogonal Partial Least Square(OPLS)model showed that the contents of Leu,Lys,and lactic acid were mainly associated with fungi,andγ-aminobutyric acid(GABA)content was correlated with Lactobacillus,Acetobacter,Leuconostoc,and Saccharomyces.This study revealed the relationship between microbial diversity and flavor compounds in persimmon vinegar produced by spontaneous fermentation.The results can provide a theoretical support for the safety and health assessment of persimmon vinegar.

Effects of Diet on the Volatile Flavor and Nutritional Ingredients of Common Octopus(Octopus vulgaris)

Cephalopods are important economic shellfish that have been developed extensively in the coastal water of various countries. Octopus vulgaris is a large-scaled economic cephalopod that is mainly cultured in South China. This study explored the effect of different diets on the volatile flavor and nutritional ingredients of O. vulgaris. Four diets were tested in four groups: Group A(fish(Scomberomorus niphonius)), Group B(crab(Helice tridens tientsinensis Rathbun)), Group C(clam(Mactra veneriformis)), and Group D(squid(Loligo japonica)). Octopus muscles were sampled after 36 days of feeding, and volatile flavor substances(VFSs), fatty acids(FAs), and amino acids(AAs) were detected. Results showed that the VFSs, FAs, and AAs of octopus in the four groups were obviously different. The sum of volatile ketones and aldehydes was higher in Group B than in the other groups, which could present much more flavors. All groups were abundant in unsaturated FAs, including eicosapentaenoic acid(EPA) and docosahexaenoic acid(DHA). In terms of content and variety, the FAs in Group B were more beneficial to human health than those in the other groups. The content of each AA in Group B was basically higher than those in the other groups and was significantly higher than that in Group D(P < 0.05). Comparing the VFSs, FAs, and AAs in samples fed with four kinds of diets, the results indicate that using crab to feed O. vulgaris can achieve better effects on volatile flavor and nutritional ingredients.