本研究探讨了木醋杆菌对复合果汁乳酸菌发酵后乳酸菌活菌数、乳酸菌对胃肠道的耐受性和主要营养成分及抗氧化能力的影响。结果表明，在30 ℃的条件下，乳酸菌在复合果汁生长迅速，发酵24 h后，活菌数均达8.50 log cfu/mL以上；单一发酵组与共发酵组经人工胃液、人工肠液消化后乳酸菌存活率均在60.00%以上，通过胆盐、体外消化后存活率均对比MRS肉汤发酵组存活率有所提高；木醋杆菌可增加乳酸菌的胆盐耐受能力。发酵后的复合果汁pH值均下降到3.90以下，葡萄糖、苹果酸和Vc含量均显著性降低(p<0.05)，乳酸含量和抗氧化活性(ORAC值)均显著性提高(p<0.05)，木醋杆菌与乳酸菌共发酵显著降低复合果汁中单糖的含量，增加乙酸和纤维素产量(p<0.05)。综上所述，木醋杆菌能够在一定程度上提高乳酸菌胃肠道耐受性，降低复合果汁的单糖含量，增加果汁的酸度和细菌纤维素的含量。

This study investigated the effects of Gluconacetobacter xylinus on the number of living Lactic acid bacteria, tolerance of Lactic acid bacteria to the gastrointestinal tract, main nutrients, and antioxidant capacity of a fermented mixed juice, were studied in this paper. The results showed that at 30 ℃, Lactic acid bacteria grew rapidly in the mixed juice. After 24 h fermentation, the number of living bacteria was over 8.50 log CFu/mL. The survival rate of Lactic acid bacteria in the single fermentation group and the co-fermentation group after digestion by simulated gastric juice and simulated intestinal juice were more than 60.00%. The survival rate of the juice fermentation group was improved by the bile salt and in vitro digestion as compared with that of the MRS broth fermentation group. Gluconacetobacter xylinus could enhance the bile salt tolerance of Lactic acid bacteria. The pH of the mixed juice after fermentation decreased to less than 3.90, the contents of glucose, malic acid and Vc all decreased significantly (p < 0.05), whilst the content of lactic acid and the antioxidant activity (oxygen radical absorbance capacity (ORAC) value) increased significantly (p < 0.05). Co-fermentation with Gluconacetobacter xylinus and Lactic acid bacteria significantly reduced the monosaccharide content in the mixed juice, but increased the yield of acetic acid and cellulose (p < 0.05). In summary, Gluconacetobacter xylinus could improve the gastrointestinal tolerance of Lactic acid bacteria to a certain extent, reduce the monosaccharide content of in the mixed fruit juice, and increase the acidity of juice and the content of bacterial cellulose.

国家自然科学基金项目（31501541）；国家重点研发计划课题（2017YFD0400703）；国家公益性行业(农业)科研专项(201503142-03)；广东省省级科技计划项目（2017B020207005）；广州市科技计划项目产学研协同创新重大专项（201704020037）