关键词: 乳杆菌, 培养物及其组分, 自由基清除率, 抗氧化酶活性

Abstract: To study on the antioxidant ability of all fermented cultures and their ingredients of Lactobacillus plantarum CGMCC 1.557 and Lactobacillus casei CGMCC 1.570, all fermented cultures, fermented supernatants, cell suspensions and intracellular extracts of the two strains were prepared separately first. Then their scavenging rates of three free radicals (DPPH·, O2·-, ·OH) and the activity of three antioxidases, including total superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), were detected to evaluate the antioxidant ability of all fermented cultures and their ingredients of the two strains. The results demonstrated that all fermented cultures of both L. plantarum and L. casei possessed good radical-scavenging ability and decent activity of T-SOD and GSH-Px. Compared with cell suspensions and intracellular extracts, fermented supernatants of both Lactobacillus had significantly higher scavenging rates of DPPH· and O2·-, and higher activity of T-SOD (P<0.05). Cell suspensions of both Lactobacillus had the highest scavenging rate of ·OH（P<0.05）. The study indicated that two strains, L. plantarum CGMCC 1.557 and L. casei CGMCC 1.570, possessed good antioxidant ability, which mainly relied on antioxidase activity of fermented supernatants and cell. The results of the research provided theoretical foundation for further development on antioxidant Lactobacillus products.

Key words: Lactobacillus, cultures and their ingredients, scavenging rate of free radicals, antioxidase activity