The aroma components in Meilanchun sesame flavor style baijiu were identified by aroma extract dilution analysis (AEDA), quantitative analysis, aroma active compound recombination, and omission/addition experiments.

Natural stilbenes have unique physiological effects, such as anti-senile dementia, anti-cancer, anti-bacterial, lowering blood lipid, and other important biological functions, which have attracted great attention from scholars in recent years. In this study, two stilbene compounds, resveratrol (RES) and polydatin (PD), were isolated from Mulberry (Morus alba L.), and their antioxidant activity and mechanism were investigated. The results showed that the contents of RES and PD in mulberry roots were 32.45 and 3.15 μg/g, respectively, significantly higher than those in mulberry fruits (0.48 and 0.0020 μg/g) and mulberry branches (5.70 and 0.33 μg/g). Both RES and PD showed high antioxidant potential by DPPH, ABTS free-scavenging methods, and ORAC assay, and provided protection against oxidative damage in HepG2 cells by increased catalase (CAT) activity, superoxide dismutase (SOD) activity, and Glutathione (GSH) content, and decreasing generation of reactive oxygen species (ROS), lactate dehydrogenase (LDH) level, and malondialdehyde (MDA) content. Therefore, RES and PD treatment could be effective for attenuating AAPH-induced oxidative stress in HepG2 cells. This study will promote the development and application of stilbene compounds. Furthermore, the RES and PD could be used as antioxidant supplements in functional foods, cosmetics, or pharmaceuticals, contributing to health improvement.

The antagonistic mechanisms of soluble non-volatile bioactive compounds, such as proteins and lipopeptides emitted from Bacillus have been widely studied. However, there are limited studies on the antifungal mechanisms of volatile organic compounds (VOCs) produced by Bacillus against plant fungal diseases. In this study, the antagonistic mechanisms of one specific VOC, 6-methyl-2-heptanone, against Alternaria solani were investigated. To optimize the extraction conditions of headspace solid-phase microextraction, a 50/30-μm divinylbenzene/carboxen/polydimethylsiloxane fiber at 50°C for 40 min was used. For gas chromatography-mass spectrometry using a free fatty acid phase capillary column, 6-methyl-2-heptanone accounted for the highest content, at 22.27%, of the total VOCs from Bacillus subtilis ZD01, which inhibited A. solani mycelial growth strongly in vitro. Therefore, 6-methyl-2-heptanone was selected as the main active chemical to elucidate the action mechanisms against A. solani. Scanning and transmission electron microscopy analyses revealed that after exposure to an EC50 dose of 6-methyl-2-heptanone, A. solani hyphal cells had a wide range of abnormalities. 6-Methyl-2-heptanone also caused the capture of cellular fluorescent green label and the release of adenosine triphosphate (ATP) from outer membranes A. solani cells, which may enhance 6-methyl-2-heptanone ability to reach the cytoplasmic membrane. In addition, 6-methyl-2-heptanone showed strong inhibitory effect on A. solani conidial germination. It also damaged conidial internal structures, with the treated group having collapsed shrunken small vesicles as observed by transmission electron microscopy. Because 6-methyl-2-heptanone showed strong effects on mycelial integrity and conidial structure, the expression levels of related pathogenic genes in A. solani treated with 6-methyl-2-heptanone were investigated. The qRT-PCR results showed that transcriptional expression levels of slt2 and wetA genes were strongly down-regulated after exposure to 6-methyl-2-heptanone. Finally, because identifying the functions of pathogenic genes will be important for the biological control of A. solani, the wetA gene was identified as a conidia-associated gene that plays roles in regulating sporulation yield and conidial maturation. These findings provide further insights into the mechanisms of VOCs secreted by Bacillus against A. solani.

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Jasminum sambac is a flower and usually used in food, cosmetics or other chemical industries for its unique flavour characteristics in China. However, molecular sensory technologies have not applied to identify aroma‐active compounds in J sambac concrete. In this study, gas chromatography‐olfactometry (GC‐O), gas chromatography‐mass spectrometry and solvent‐assisted flavour evaporation were applied to isolate the odorants in three Chinese J sambac concrete (E1, E2 and E3) obtained from different companies. A total of forty‐nine, forty‐eight, thirty‐nine odorants were screened by GC‐O with aroma extract dilution analysis in E1, E2 and E3, respectively. The higher flavour dilution (FD) factors were linalool (19 683‐59 049, floral), methyl anthranilate (6561‐19 683, grape‐like) and benzyl acetate (2187‐19 683, floral). Twenty‐two aroma compounds were quantitated by gas chromatography‐flame ionization detection with internal standard, and then their odour activity values were obtained. Linalool, cis‐3‐hexenyl acetate, linalyl acetate, eugenol and methyl salicylate contributed greatly to the aroma of J sambac concretes. The aroma recombination model was established by mixing twenty‐two key odorants based on their measured concentrations, and the result revealed that the overall aroma profile was similar to that of the original sample. These results proved basic data for improvement of the national standard of jasmine concrete.