Effects and Potential Risks of Chiral Penflufen on Pickled Cowpea: Combined Microbiome and Metabolomics

Pesticide residues on vegetables may affect microbes and metabolites during the fermentation process, leading to effects and potential risks. Here, the enantioselective effects and potential risks of chiral penflufen on pickled cowpea were investigated by using microbiome and metabolomics analyses. Correlation analysis was conducted to construct bacterial-metabolite interaction networks. Penflufen enantiomers were degraded little during the fermentation process. Rac-penflufen treatment significantly decreased the relative abundance of Lactiplantibacillus while increasing Weissella, but the opposite effects were found in R- and S-penflufen treatments. These shifts were linked to content and functional changes of metabolites. R-/S-/Rac-penflufen upregulated rose aroma metabolites (e.g., β-damascenone), while R- and S-penflufen downregulated floral aroma metabolites (e.g., β-ionone, 2-nonenal) and green leaf aroma metabolites (e.g., (E)-2-hexenal). S-Penflufen reduced alcohols and increased esters more significantly, and altered a higher number of volatile organic compounds (VOCs) and chiral amino acids than R-penflufen, showing a greater risk to food flavor and nutritional quality.