探究了经嗜酸乳杆菌LA-5发酵的红甜菜汁对血管紧张素转化酶（ACE）、乙酰胆碱酯酶（AChE）的抑制能力、抗氧化活性影响及其与活性物质的关系。结果表明：发酵结束时活菌数为6.29×108 CFU/mL，甜菜红素和总酸含量分别增加了13.63%和302.21%，还原糖、甜菜黄素和黄酮含量分别降低了63.87%、43.09%和0.05%。经发酵后·O2-、·OH和ABTS+·清除率分别提高29.13%、96.36%和77.49%，AChE和ACE抑制率分别提高59.15%和35.37%，各时间段发酵液经UHPLC-Q-TOF-MS/MS共鉴定出12种甜菜色素。相关性分析表明上述功能性指标与甜菜红素呈极显著正相关（p<0.01）；主成分分析共提取3个主成分，总贡献率为90.63%，其中betanin、betanidin、17-decarboxy-betanidin、2-decarboxy-neobetanin、6ˊ-O-feruloyl-betanin、vulgaxanthin I、betalamic acid为主要活性成分；Q型聚类分析将发酵过程聚为3类，即缓慢增长期、显著变化期和平缓期；R型聚类分析将活性成分和功能指标聚为3类，与相关性分析和主成分分析结果一致。综上所述，经嗜酸乳杆菌LA-5发酵的红甜菜汁是一种以甜菜红素为主的优质抗氧化剂和AChE、ACE抑制剂来源，具有开发防治阿尔兹海默症相关功能性产品的价值。

The effects of red beetroot juice fermentation by Lactobacillus acidophilus LA-5 on the activity of angiotensin-converting enzyme (ACE), acetylcholinesterase (AChE), and antioxidants, and its relationship with active substances were studied. The number of viable bacteria at the end of fermentation was 6.29×108 CFU/mL. The contents of betacyanins and total acid increased by 13.63% and 302.21%, respectively. The contents of reducing sugar, betaxanthins, and flavones decreased by 63.87%, 43.09%, and 0.05%, respectively. After fermentation, the clearance rates of ·O2-, ·OH, and ABTS+· increased by 29.13%, 96.36%, and 77.49%, respectively, and the inhibition rates of AChE and ACE increased by 59.15% and 35.37%, respectively. Twelve betalains were identified by UHPLC-Q-TOF-MS/MS. Correlation analysis showed that the aforementioned functional indexes had a very significant positive correlation with the betacyanin content (p<0.01). Three principal components, with a total contribution rate of 90.63%, were extracted using principal component analysis. The main active components were betanin, betanidin, 17-decarboxy-betanidin, 2-decarboxy-neobotanin, 6ʹ-O-ferroyl-betanin, vulgaxanthin I, and betalamic acid. Q-type cluster analysis classified the fermentation process into three categories: slow growth, significant change, and flat periods. R-type cluster analysis grouped the active components and functional indexes into three categories. In summary, red beetroot juice fermented by L. acidophilus LA-5 is a source of high-quality antioxidants, as well as AChE and ACE inhibitors dominated by betacyanins, which prevent the development of Alzheimer’s disease.