Exploring The Microbial Dynamics And Flavor Of Traditional Qishan Brewing Vinegar

Chinese traditional cereal vinegar was brewed by cereal through multispecies solid-state fermentation in an open environment.It is essential to investigate the microbial diversity during vinegar fermentation process and flavor for improving the quality of vinegar.The Daqu and vinegar Pei were investigated the microbial diversity by Illumina HiSeq sequencing,and unsterilized vinegar was detected the flavor formation by HPLC,L8900 and HS-SPME-GC-MS,respectively.The prevailing bacteria in Daqu were Weissell,Pseudomonas,Bacillus,Lactobacillus,Stenotrophomonas;the dominant fungi were Saccharomycopsis.However,the physiochemical variation and microbial diversity were highly similar during acetic acid fermentation no matter how significant difference in starter Daqu including Chao Daqu and mature Daqu were used in vinegar fermentation.These results demonstrated that robustness was existed during acetic acid fermentation.The dominant bacteria during acetic acid fermentation were Lactobacillus,Acetobacter,Weissella,Pseudomonas,Leuconostoc,Stenotrophomonas,Streptococcus,Acinetobacter,Bacillus,Cupriavidus.The unsterilized vinegar was investigated organic acid,amino acid and volatile flavor by HPLC,L8900 and HS-SPME-GC-MS,respectively.The six-organic acid accumulated of unsterilized vinegar contains 12 g/100 ml,and the characterized organic of Qishan vinegar were acetic acid,lactic acid and citric acid.In addition,glutamic acid,leucine,arginine,alanine and phenylalanine were the characterized amino acid in Qishan vinegar.Furthermore,volatile compounds including 20 esters,9 acids,8 aldehydes,7 alcohols,3 ketones,2 ethers,2 pyrazines were detected in unsterilized vinegar.The ethyl acetate,ethyl lactate,sugar aldehyde,3-hydroxyl-2-butanone were related rich in vinegar and also were the characterized volatile flavor.Qishan vinegar contains the tetramethylpyrazine and dimethylpyrazine and it's important for the vinegar for the health function.This study confirmed the core microbiota during vinegar brewing process and chemical coupounds in vinegar,it will aid in upgrading the vinegar brewing technology and improving the quality and safety of vinegar products.