Abstract:Potato pickles were produced by fermentation with a combination of four probiotic strains，and the naturally fermented potato pickles were used as the control group.The untargeted metabolomics based on ultrahigh performance liquid chromatography-tandem mass spectrometry was employed to analyze the metabolites in potato pickles.Based on the thresholds of fold change≥2 or≤0.5 and P＜0.05，511，525，and 105 differentially changed metabolites（DCMs）were identified between fresh raw material（XX）and inoculated fermentation for 5 days（JZD5），between XX and natural fermentation for 5 days（ZRD5），and between ZRD5 and JZD5，respectively.The DCMs between XX and JZD5/ZRD5 were mainly D-ornithine，L-ornithine，4-carboxyphenylglycine，glycyl phenylalanine，L-tyrosine-L-serine，tri-carbonyl propionic acid，2-amino-4-oxvaleric acid，and other bioactive substances and small peptides，which contributed to the nutritional value and unique flavor of potato pickles.The DCMs between ZRD5 and JZDR5 included 6-aminocaproic acid，DL-leucine，theanine，and isocitric acid，which were the main bioactive substances and flavor components of potato pickles.Sugar alcohols and organic acids had high content in JZD5，which endowed the potato pickles with a taste superior to that of naturally fermented potato pickles.In addition，the results showed that the metabolic pathways such as ABC transporters，glyoxylic and dicarboxylic acid metabolism，purine metabolism，and cofactor biosynthesis played important roles in the quality formation of potato pickles during fermentation.