利用植物乳杆菌PJ4-2发酵蜜本南瓜汁，以未发酵的南瓜汁为对照，分析利用植物乳杆菌PJ4-2发酵后南瓜汁理化指标、挥发性风味物质及感官品质的变化。结果表明：经过12 h发酵，南瓜汁pH值下降至4.52，酸度上升至10.70 mg/g，有机酸含量上升至11.64 mg/g。利用顶空固相微萃取和气相色谱-质谱联用技术（HS-SPME-GC-MS）从发酵前后的南瓜汁中共鉴定出40种挥发性风味物质，包括11种醛、9种酮、11种醇、4种烯烃、1种酚、1种酯、1种酸和2种其他物质，发酵后挥发性风味物质浓度增加了67.60%，植物乳杆菌PJ4-2对增加南瓜汁风味有重要贡献。结合香气活性值（OAV）分析以及偏最小二乘回归分析（PLS-DA）可知，南瓜汁发酵后香气差异的特征性潜在标记物为2,3-丁二酮（OAV=175.10，VIP=1.51）和3-羟基-2-丁酮（OAV=10.18，VIP=1.40），赋予发酵南瓜汁黄油香气。结果表明，植物乳杆菌PJ4-2在南瓜汁具有较好活性，发酵后南瓜汁香味浓郁、酸甜适中，整体接受度更高，植物乳杆菌PJ4-2适用于发酵南瓜汁。

Cucurbita maxima pumpkin juice was fermented by Lactiplantibacillus plantarum PJ4-2, and theunfermented pumpkin juice was used as the control. The changes in physicochemical indexes, volatile flavor substances and sensory quality of the pumpkin juice after fermentation with L. plantarum PJ 4-2 were analyzed. The results showed that after a 12-h fermentation, the pH value of the pumpkin juice decreased to 4.52, the acidity increased to 10.70 mg/g, and the content of organic acid increased to 11.64 mg/g. A total of 40 volatile flavor compounds were identified from the unfermented and fermented pumpkin juices by headspace solid-phase microextraction and gas chromatography-mass spectrometry (HSSPME-GC-MS), including 11 aldehydes, 9 ketones, 11 alcohols, 4 olefins, 1 phenol, 1 ester, 1 acid and 2 other compounds. The concentration of volatile flavor substances increased by 67.60% after fermentation, and L. plantarum PJ 4-2 made an important contribution to the increase of pumpkin juice flavor. The odor activity value (OAV) analysis combined with the partial least squares discriminant analysis (PLS-DA) revealed that 2,3-butanedione (OAV=175.10, VIP=1.51) and 3-hydroxy- 2-butanone (OAV=10.18, VIP=1.40) were the potential characteristic markers for the aroma differences of pumpkin juice before and after fermentation, giving the fermented pumpkin juice a buttery aroma. The results showed that L. plantarum PJ4-2 had a good activity in pumpkin juice, and the resulting fermented pumpkin juice was rich in fruity aroma, had moderate sweetness and sourness, and gained higher overall acceptance, indicating that L. plantarum PJ4-2 was suitable for fermentation of pumpkin juice.

山东省自然科学基金面上项目（ZR2021MC153）；烟台市科技计划项目（2022XDRH013）