Characteristics and Discrimination of the Commercial Chinese Four Famous Vinegars Based on Flavor Compositions.

Shanxi aged vinegar (SAV), Zhenjiang aromatic vinegar (ZAV), Sichuan bran vinegar (SBV), and Fujian monascus vinegar (FMV) are the representative Chinese traditional vinegars. However, the basic differential compositions between the four vinegars are unknown. In this study, compositions of commercial vinegar were investigated to evaluate the influence of diverse technologies on their distinct flavor. Unlike amino acids and organic acids which were mostly shared, only five volatiles were detected in all vinegars, whereas a dozen volatiles were common to each type of vinegar. The four vinegars could only be classified well with all compositions, and difference analysis suggested the most significant difference between FMV and SBV. However, SAV, ZAV, and SBV possessed similar volatile characteristics due to their common heating treatments. Further, the correlation of identification markers with vinegars stressed the contributions of the smoking process, raw materials, and Monascus inoculum to SAV, SBV, and FMV clustering, respectively. Therefore, regardless of the technology modification, this basic process supported the uniqueness of the vinegars. This study contributes to improving the standards of defining the characteristics of types of vinegar.

ß-aminobutyric acid (BABA)-induced resistance to tobacco black shank in tobacco (Nicotiana tabacum L.).

Tobacco black shank is a kind of soil-borne disease caused by the Oomycete Phytophthora parasitica. This disease is one of the most destructive diseases to tobacco (Nicotiana tabacum L.) growth worldwide. At present, various measures have been taken to control this disease, but they still have different challenges and limitations. Studies have shown that ß-aminobutyric acid (BABA), a nonprotein amino acid, can enhance disease resistance in plants against different varieties of pathogens. However, it is unclear whether BABA can induce plants to resist Phytophthora parasitica infection. Therefore, this study aims to explore the effect and related mechanism of BABA against tobacco black shank. Our results showed that 5 mmol.L-1 BABA had an obvious anti-inducing effect on the pathogenic fungus and could effectively inhibit the formation of dark spots in the stems. The results also showed that a large amount of callose deposition was observed in BABA-treated tobacco. Furthermore, the application of BABA induced the accumulation of H2O2 in tobacco and effectively regulated the homeostasis of reactive oxygen in tobacco plants, reducing the toxicity of H2O2 to plants while activating the defense system. In addition, BABA spray treatment could induce an increase in the concentrations of salicylic acid (SA) and jasmonic acid-isoleucine (JA-Ile) in tobacco, and the gene expression results confirmed that BABA upregulated the expression of SA-related genes (PR1, PR2 and PR5), JA-related genes (PDF1.2) and ET-related genes (EFE26 and ACC oxidase) in tobacco plants. Taken together, BABA could activate tobacco resistance to black shank disease by increasing H2O2 accumulation, callose deposition, plant hormone (SA and JA-Ile) production, and SA-, JA-, and ET- signaling pathways.

Effect of changing the melanoidins by decoction on the release of volatiles in Zhenjiang aromatic vinegar.

Melanoidins, making general contribution to the food characteristics, are extensively generated in the production of Chinese traditional vinegar; however, their effect on flavor modification remains unknown. This study investigated the changes in the melanoidins of Zhenjiang aromatic vinegar (ZAV) during decoction, and the interactions of crude melanoidins (CM) and pure melanoidins (PM) from decocted and undecocted ZAV with mixed aroma compounds were compared. With the exception of CN, OH and CH, chemical bonds and groups varied among the four types of melanoidins. However, CM and PM, obtained from decocted or undecocted vinegar, displayed generally similar structures, which resulted in their consistent retention of volatiles owning to the overall structure characteristics. Compared to aqueous solution, CM and PM from undecocted vinegar exhibited release, non-influence, or adsorption of flavors. However, melanoidins from decocted vinegar appeared the adsorption for all flavors but 2,3,5,6-Tetramethylpyrazine with weakened release. Free low molecular weight (LMw) compounds would affect the volatiles retention. Total solids (TS) from undecocted vinegar adsorbed volatiles except diethyl succinate; however, TS from decocted vinegar released all flavors significantly. Therefore, the decocted melanoidins were beneficial for the persistence of aroma. This study provided a base for elucidating the formation of melanoidins in decoction procedure and their roles in flavor modification.