Abstract:In order to compare the change of volatile components in Lactobacillus helveticus fermentation pumpkin juice during 0，24，36，48 h，the volatile compounds were detected by using headspace-solid-phase microextraction combined with gas chromatography-mass spectrometry.The results showed that microbes could increase species and content of flavor substances in pumpkin juice and those existed differences in different fermentation time.29 kinds of volatile components were identified with 0 h fermentation and mainly included hexanal（12.72%），2-methyl butyl aldehyde（6.61%） and 2，4-2 tertiary butyl phenol（6.17%）.44 kinds of volatile components were identified with 12 h fermentation and mainly included 3-hydroxy-2-butanone（31.56%），2，3-dione（11.06%）and acetone（6.95%）.44 kinds of volatile components were identified with 24 h fermentation and mainly included 3-hydroxy-2-butanone（38.87%），2，3-dione（12.35%）and acetone（5.24%）.40 kinds of volatile components were identified with 36 h fermentation and mainly included 3-hydroxy-2-butanone（47.22%）and 2，3-dione（7.15%），acetic acid（5.26%）.38 kinds of volatile components were identified with 48 h fermentation and mainly included 3-hydroxy-2-butanone （32.36%）and 2，3-dione（7.79%），acetic acid （5.83%）.On the sensory，Lactobacillus could significantly affect the flavor of fermented pumpkin juice.Lactobacillus helveticus tended to convert aldehydes and alcohols into ketones and acids.The score of fermented pumpkin juice for 12 h was the highest.