果蔬发酵液中3株乳杆菌的体外功能特性研究

以果蔬自然发酵液中分离得到的3株乳杆菌（Lactobacillus）为对象，通过测定表面疏水性、自身凝聚率分析乳杆菌的表面特性；以DPPH自由基、ABTS自由基清除能力和铁还原能力为指标，分析3株乳杆菌的体外抗氧化能力差异；以降解胆固醇及亚硝酸盐为指标，评价乳杆菌的功能活性。结果表明:3株菌中，L3的表面疏水性和自身凝聚力均表现良好，分别为57.7%和95.2%（24 h）；3株菌的上清液具有很强的DPPH自由基清除率（>90%）、羟自由基清除率（>68%）及还原能力（>1.0），其中L1和L3的上清液具有更强羟自由基清除率，近90%，L2则具有较强的抗脂质过氧化能力（>37%）；乳杆菌在48 h内几乎完全降解200 mg/L NaNO₂；3株菌上清液均有较好的胆固醇降解能力（>19%），其活性物质主要为蛋白质和多糖类物质。综上所述，果蔬发酵液中分离所得的3株乳杆菌表现出了良好的益生特性，可为开发功能性发酵食品奠定坚实的基础。

Study on in Vitro Functional Characteristics of Three Strains of Lactobacillus in Fruit and Vegetable Fermentation Broth

Taking 3 strains of Lactobacillus isolated from fruits and vegetables natural fermentation broth as the object, the surface characteristics of Lactobacillus were analyzed by measuring the surface hydrophobicity and self-aggregation rate; DPPH free radical scavenging ability, ABTS free radical scavenging ability and iron reducing ability were used as indexes to analyze the difference of antioxidant ability of three Lactobacillus strains in vitro; to evaluate the functional activity of Lactobacillus using cholesterol and nitrite degradation as indicators. The results showed that among the three strains, L3 had good surface hydrophobicity and self-aggregation rate, which were 57.7% and 95.2% (24 h) respectively; The supernatants of the three strains had stronger DPPH radical (>90%) and hydroxyl radical clearance (>68%) and reduction ability (>1.0), among which L1 and L3 supernatant had stronger hydroxyl radical clearance, nearly 90% and L2 had stronger anti-lipid peroxidation ability (>37%); Lactobacillus almost completely degraded 200 mg/L NaNO₂ within 48 h; The supernatants of the three strains had good cholesterol degradation ability (>19%), and their active substances were mainly proteins and polysaccharides. In summary, the three strains of Lactobacillus isolated from the fermentation broth of fruits and vegetables show good probiotic properties, which can lay a solid foundation for the development of functional fermented foods.