Abstract:The seeds were optimized by single factor and orthogonal test，and the quality and flavor characteristics of natural and probiotic fermented pumpkin seeds were compared by automatic amino acid analyzer and GC-MS.The results showed that the optimal conditions for preparing pumpkin seeds by probiotic fermentation were fermentation time 5 d，inoculation amount 5%，strain ratio 1∶1∶1，fermentation temperature 36 ℃.The pH value of pumpkin seeds was 7.1，and sensory score was 20.The contents of bitter amino acids in pumpkin seeds fermented by probiotics decreased，but the contents of sweet amino acids increased.A total of 27 volatile components were detected.Compared with natural fermentation，the relative contents of volatile flavor substances in probiotic fermentation were significantly increased.Factor analysis showed that Lactobacillus plantarum and saccharomyces cerevisiae contributed more to the production of pumpkin seed ester in probiotic fermentation.