The quality and flavor of chicken are affected by muscle metabolites and related regulatory genes, and the molecular regulation mechanism of meat quality is different among different breeds of chicken. In this study, 40 one-day-old Daweishan mini chicken (DM) and Cobb broiler (CB) were selected from each group, with 4 replicates and 10 chickens in each replicate. The chickens were reared until 90 d of age under the same management conditions. Then, metabolomics and transcriptomics data of 90-day-old DM (n = 4) and CB (n = 4) were integrated to analyze metabolites affecting breast muscle quality and flavor, and to explore the important genes regulating meat quality and flavor related metabolites. The results showed that a total of 38 significantly different metabolites (SDMs) and 420 differentially expressed genes (DEGs) were detected in the breast muscle of the 2 breeds. Amino acid and lipid metabolism may be the cause of meat quality and flavor difference between DM and CB chickens, involving metabolites such as L-methionine, betaine, N6, N6, N6-Trimethyl-L-lysine, L-anserine, glutathione, glutathione disulfide, L-threonine, N-Acetyl-L-aspartic acid, succinate, choline, DOPC, SOPC, alpha-linolenic acid, L-palmitoylcarnitine, etc. Important regulatory genes with high correlation with flavor amino acids (GATM, GSTO1) and lipids (PPARG, LPL, PLIN1, SCD, ANGPTL4, FABP7, GK, B4GALT6, UGT8, PLPP4) were identified by correlation analysis, and the gene-metabolite interaction network of breast muscle mass and flavor formation in DM chicken was constructed. This study showed that there were significant differences in breast metabolites between DM and CB chickens, mainly in amino acid and lipid metabolites. These 2 kinds of substances may be the main reasons for the difference in breast muscle quality and flavor between the 2 breeds. In general, this study could provide a theoretical basis for further research on the molecular regulatory mechanism of the formation of breast muscle quality and flavor differences between DM and CB chickens, and provide a reference for the development, utilization and genetic breeding of high-quality meat chicken breeds.

Pelodiscus sinensis is an aquatic product with a long growth cycle in pond culture and high nutritional value meat. The flavor compounds, nutrients, and lipidome were investigated to explore the edible value changes of turtle meat aged 3 to 6 years (Y3 to Y6). Typically, P. sinensis meat is rich in high-quality protein (EAAI ≥81.22, AAS ≥86.47). Y6 has the highest level of Se, protein, amino acids, and high unsaturated fatty acids, including EPA + DHA. Y5 has the most delicious amino acids, polyunsaturated fatty acids, and key odorant content. The stronger flavor of Y5 may be mainly related to C18:2n6t and C18:2n6c. Further, triacylglycerols (TAG) and phosphatidylcholine (PC) were significant changes in Y5. Additionally, PI (16:0/18:1) was identified as the potential biomarker. These results provided available information on P. sinensis marketing age and revealed the potential impact of nutrients on the formation of VOCs.

The biocatalytic aerobic \"in-water\" reduction of anthranilic acid to 2-aminobenzaldehyde by growing cultures of the basidiomycetous white-rot fungus Bjerkandera adusta has been studied. The high specific activity of Bjerkandera adusta towards the carboxylic group of anthranilic acid that allows avoiding the formation of the corresponding alcohol has been demonstrated using different substrate concentrations. The presence of ethanol as co-solvent allows increasing the yield of target product. In contrast to chemical reducing agents that usually yield 2-aminobenzyl alcohol, an overreduction of anthranilic acid is completely suppressed by the fungus and gives the target flavor compound in satisfactory preparative yields. It was shown that the activity of Bjerkandera adusta towards anthranilic acid does not apply to its m- and p-isomers.

This study was aimed to identify and compare the taste-related compounds (nucleotide-related compounds, free amino acid contents, and fatty acid composition) and aroma (volatile organic compounds [VOC]) compounds in the chicken breast meat from 3 kinds of Korean native chicken (KNC), namely Hanhyup 3 (HH3), Woorimatdag 1 (WRMD1) and Woorimatdag 2 (WRMD2). Among the 3 breeds, WRMD1 had significantly higher IMP and AMP contents than HH3. WRMD2 exhibited higher levels of umami and sweet-taste amino acids and oleic acid composition compared to HH3 (P < 0.05). HH3 showed a higher composition of unsaturated fatty acids than WRMD2 (P < 0.05). On their discrimination by flavor composition, some compounds including aspartic acid were analyzed as important compounds. Regarding aroma compounds, unique aroma compounds were detected for each breed and some compounds such as isopropyl myristate, p-cresol, (S)-(+)-3-Methyl-1-pentanol, and cyclic octa-atomic sulfur were expected to be utilized as key compounds in discrimination of the 3 breeds. From the result of this study, the differences on the flavor compounds of three breeds were elucidated and key compounds for their discrimination were presented.

Maillard reaction products (MRP) contribute to sensory quality of various foods. Whole grains (WG) are rich in phenols which may influence Maillard reaction pathways during thermal processing and impact WG product sensory attributes. This study investigated how WG phenolic profile affects MRP formation. Amylase-hydrolyzed wheat (white and red) and sorghum (white, red, tannin) brans were hydrothermally processed at 150 °C/6 min, and characterized for MRP using colorimetry, fluorescence spectroscopy, HPLC-MS/MS, and HS-SPME/GC-MS. Bran phenolic structure, and to a lesser extent content, had larger influence on MRP formation than protein/amino acid profile. Polymeric tannins (both in situ and when added to wheat brans) strongly inhibited volatile and non-volatile MRP intermediates and melanoidin formation, likely via their carbocation depolymerization intermediates trapping furans. Principle component analysis demonstrated clear segregation of volatiles formation based on bran phenolic profile. Phenolic composition should be considered in WG product formulation and processing to achieve desired MRP formation.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and its global incidence is estimated to be 24%. Beer, wine, and Chinese baijiu have been consumed worldwide including by the NAFLD population. A better understanding of the effects of these alcoholic beverages on NAFLD would potentially improve management of patients with NAFLD and reduce the risks for progression to fibrosis, cirrhosis, and hepatocellular carcinoma. There is evidence suggesting some positive effects, such as the antioxidative effects of bioactive flavor compounds in beer, wine, and baijiu. These effects could potentially counteract the oxidative stress caused by the metabolism of ethanol contained in the beverages. In the current review, the aim is to evaluate and discuss the current human-based and laboratory-based study evidence of effects on hepatic lipid metabolism and NAFLD from ingested ethanol, the polyphenols in beer and wine, and the bioactive flavor compounds in baijiu, and their potential mechanism. It is concluded that for the potential beneficial effects of wine and beer on NAFLD, inconsistence and contrasting data exist suggesting the need for further studies. There is insufficient baijiu specific human-based study for the effects on NAFLD. Although laboratory-based studies on baijiu showed the antioxidative effects of the bioactive flavor compounds on the liver, it remains elusive whether the antioxidative effect from the relatively low abundance of the bioactivate compounds could outweigh the oxidative stress and toxic effects from the ethanol component of the beverages.

Sichuan sun vinegar (SSV) is a traditional Chinese vinegar with a unique flavor and it is fermented with bran as the main raw material. In the present study, we explored the bacterial community succession in fermented grains (Cupei) during SSV production. High-throughput sequencing results showed that bacterial community richness and diversity peaked on day 7 of fermentation. Lactobacillus and Acetobacter were the dominant bacteria throughout the fermentation process. However, Acetobacter, Cupriavidus, Sphingomonas, Pelomonas, and Lactobacillus were the most abundant genera in the late phase of fermentation on day 17. The boundaries of trilateral co-fermentation were determined through cluster analysis. Days 1-3 were considered the early fermentation stage (starch saccharification), days 5-11 were the middle fermentation stage (alcoholic fermentation), and days 13-17 represented the late fermentation stage (acetic acid fermentation). Changes in flavor compounds during Cupei fermentation were subsequently analyzed and a total of 86 volatile compounds, 9 organic acids, and 17 amino acids were detected. Although acetic acid, lactic acid, alcohols, and esters were the main metabolites, butyrate was also detected. Correlation analysis indicated that 20, 21, and 28 microorganisms were positively correlated with the abundance of amino acids, organic acids, and volatile flavor compounds, respectively. We further explored the microbial and metabolic mechanisms associated with the dominant volatile flavor compounds during SSV fermentation. Collectively, the findings of the current study provide detailed insights regarding the fermentation mechanisms of SSV, which may prove relevant for producing high-quality fermented products.

Actinomycetes (a group of filamentous bacteria) are the dominant microbial order in the Daqu (DQ) fermentation starter and in the pit mud (PM) of the Baijiu fermentation microbiome. Actinomycetes produce many of the key enzymes and flavor components, and supply important precursors, which have a major influence on its characteristic aroma components, to other microorganisms during fermentation. This paper reviews the current progress on actinomycete research related to Baijiu fermentation, including the isolation and identification, distribution, interspecies interactions, systems biology, and main metabolites. The main metabolites and applications of the actinomycetes during Baijiu fermentation are also discussed.

Microbes in pit mud play key roles in fermentation cellars for Chinese strong-flavor Baijiu (SFB) production. Pit mud, however, is frequently degraded during production, compromising the quality of the end product. In this study, a bioremediation method was used to restore degraded pit mud (DPM) using indigenous microbes derived from SFB production. Metabolomics and metagenomics were used to determine the dynamics of prokaryotes during DPM restoration and their link to SFB production. The composition of flavor compounds in SFB changed (P = 0.0001) before and after restoration of DPM. Consistent with the improved sensory quality, the ethyl caproate/ethyl lactate ratio, an SFB quality measure, increased after restoration (P < 0.001). The concentrations of humus, NH4+, available phosphorus, and available potassium in DPM increased during the restoration process (P < 0.05), which is consistent with high-quality pit mud. The relative abundance of microbes that are beneficial to SFB fermentation, such as Caproiciproducens, a bacterium that produces caproic acid, increased during the restoration process. Furthermore, a total of 18 metabolic pathways were enriched (P < 0.05) from DPM before and after restoration. This includes butanoate metabolism and pyruvate metabolism, which are related to the synthesis of key flavor esters in SFB.

The influence of the molecular structures of flavor compounds (specifically, variations in chain length and functional groups) on the binding of the flavor compounds (Z)-2-penten-1-ol, hexanal, and (E)-2-octenal to pea protein was investigated. The results showed that the molecular structures of the flavor compounds strongly influenced their binding affinity for pea protein. Specifically, (E)-2-octenal exhibited a higher binding affinity and a higher Stern-Volmer constant with pea protein than both hexanal and (Z)-2-penten-1-ol. Thermodynamic analysis indicated that the flavor compound-pea protein interactions were spontaneous. Hydrophobic interactions were dominant in the non-covalent interactions between (E)-2-octenal/(Z)-2-penten-1-ol and pea protein, whereas hydrogen bonding was dominant in the non-covalent interactions between hexanal and pea protein. Surface hydrophobicity measurements, the use of bond-disrupting agents, and molecular docking further supported the hypothesis that hydrogen bonding, as well as hydrophobic interactions, occurred between the flavor compounds and pea protein.