Microbial community succession and their relationship with the flavor formation during the natural fermentation of Mouding sufu.

Mouding sufu, a traditional fermented soybean product in China, has been recognized by the public in the southwestern regions of China. To reveal the microbial community succession and their relationship with the flavor formation during the natural fermentation of Mouding sufu, microbial community, non-volatile flavor compounds and volatile flavor compounds were analyzed by high-throughput sequencing, high-performance liquid chromatography, gas chromatography ion migration spectroscopy, respectively. The results showed that Lactobacillus and Klebsiella were the most abundant bacterial genus, whereas the main fungal genera were unclassified-f-Dipodascaeae and Issatchenkia. In addition, Glutamic acid, Aspartic acid, Alanine, Valine, Lysine, Histidine, lactic acid, succinic acid, and acetic acid were the main non-volatile flavor substances. Furthermore, the taste activity values of glutamic acid, aspartic acid and lactic acid reached 132, 68.9, 18.18 at H60, respectively, meaning that umami and sour were the key taste compounds. Simultaneously, ethyl 3-methylbutanoate-M, ethyl propanoate, methyl 2-methylbutanoate, ethyl 2-methylbutanoate, ethyl 3-methylbutanoate-D, ethyl isobutyrate, linalool-M, linalool-D, cis-4-heptenal, 2-methylpropanal were the characteristic volatile flavor of Mouding sufu. Finally, correlation analysis showed that g__Erwinia and g__Acremonium correlated with most of the key aroma compounds. 20 bacteria and 21 fungi were identified as core functional microbe for Mouding sufu production.

Effects of exogenous sulfur on alleviating cadmium stress in tartary buckwheat.

Supplying exogenous sulfur-rich compounds increases the content of glutathione(GSH) and phytochelatins(PCs) in plant tissues, enabling plants to enhance their cellular defense capacity and/or compartmentalize Cadmium(Cd) into vacuoles. However, the mechanism by which surplus S modulates tolerance to Cd stress in different tissues need further investigation. In the present study, we found that supplementing the tartary buckwheat(Fagopyrum tararicum) exposed to Cd with surplus S reversed Cd induced adverse effects, and increased Cd concentrations in roots, but decreased in leaves. Further analysis revealed that exogenous S significantly mitigated Cd-induced oxidative stress with the aids of antioxidant enzymes and agents both in leaves and roots, including peroxidase(POD), ascorbate peroxidase(APX), glutathione peroxidase(GPX), glutathione S-transferase(GST), ascorbic acid(AsA), and GSH, but not superoxide dismutase(SOD) and catalase(CAT). The increased Cd uptake in root vacuoles and decreased translocation in leaves of exogenous S treated plants could be ascribed to the increasing Cd binding on cell walls, chelation and vacuolar sequestration with helps of non-protein thiols(NPT), PCs and heavy metal ATPase 3(FtHMA3) in roots, and inhibiting expression of FtHMA2, a transporter that helps Cd translocation from roots to shoots. Results provide the fundamental information for the application of exogenous S in reversal of heavy metal stress.

Effects of sanshoamides and capsaicinoids on plasma and liver lipid metabolism in hyperlipidemic rats.

The objective of this study was to determine the effects of sanshoamides and capsaiciniods on plasma and liver lipid levels and the mRNA expression levels of key receptors involved in cholesterol metabolism in hyperlipidemic rats. A total of 56 three-week-old female Sprague-Dawley rats were assigned to 7 treatment groups based on initial body weight (n = 8 rats per group). With certain combinations of sanshoamides and capsaicinoids significantly increased food intake, reduced lipid levels in blood and liver, improved histological characteristics of a fatty liver, down regulated mRNA expression levels of cholesterol 7-alpha-hydroxylase (CYP7A1), 3-hydroxyl-3-methylglutary CoA (HMG-CoA) and Farnesoid X Receptor (FXR) in liver and apical sodium-dependent bile acid transporter, Ileal Bile Acid Binding Protein and FXR in the ileum in hyperlipidemic rats. These results indicated that dietary supplementation with sanshoamides and capsaicinoids reduced blood lipid levels and improved cholesterol metabolism in hyperlipidemic rats.