本研究运用紫外分光光度法初筛，再以HPLC法进行复筛，从31株源自云南传统发酵食品的乳酸菌中筛选具有高效ACE抑制活性菌株，同时研究其益生特性及脱脂乳发酵过程中ACE抑制率的动态变化。综合各项研究结果，最终筛选出ACE抑制率较高、抑菌谱广、耐酸耐胆盐性强，且对抗生素敏感的Lactobacillus plantarum YM-4-3作为研究菌株。益生特性研究表明，该菌株对Escherichia coli O 157：H 7和Listeria monocytogenes的抑菌圈直径可分别达41.30 mm和42.00 mm，甚至在高胆盐（0.3%）及强酸（pH 2.5）处理后仍保持较高活菌数（大于105 cfu数量级）。脱脂乳发酵过程中ACE抑制活性的动态监测表明，37 ℃发酵48 h是Lb. plantarum YM-4-3菌株发酵产生ACE抑制肽的最适培养条件，该发酵条件下获得的发酵乳的ACE抑制率可高达81.23%，菌体生物量、游离氨基酸及多肽含量也均达到最大值。本研究成果将为新型具有高效ACE抑制活性发酵乳制品的研发提供理论依据及菌株保证。

A lactic acid bacterium with high angiotensin-I converting enzyme (ACE)-inhibitory activity was screened from 31 isolates obtained from traditional fermented foodsin Yunnan. The isolates were preliminarily screened by ultraviolet (UV) spectrophotometry, followed by high-performance liquid chromatography (HPLC). Potential probiotic properties and dynamic changes in ACE inhibitory activity during skim milk fermentation were evaluated. Lactobacillus plantarum YM-4-3 strain was selected owing to its high ACE inhibitory activity, broad antibacterial spectrum, sensitivity to antibiotics, and strong tolerance to acid and bile. The inhibition zone diameters of Lactobacillus plantarum YM-4-3 against Escherichia coli O157:H7 and Listeria monocytogenes were 41.30 and 42.00 mm, respectively.After treatment with strong acid (pH 2.5) and high concentration of bile salt (0.3%), the viable cell count was still above 105 CFU/mL. The dynamic monitoring of ACE inhibitory activity of Lactobacillus plantarum YM-4-3 during the fermentation of skim milk indicated that the optimum condition for Lactobacillus plantarum YM-4-3 to produce ACE inhibitory peptide was 37 ℃ for 48 h. Under this condition, the ACE inhibition rate of fermented milk reached 81.23%, and the maximum biomass of the strain and the highest content of free amino acid and polypeptides in fermented milk were achieved. This study can provide a theoretical basis and a candidate bacterium for the study and development of a novel, functional fermented milk beverage, with high ACE inhibitory activity.

益生菌的生理保健机能及应用（14078326）