【摘要】 微生物胞外多糖具有良好的抗氧化能力，为了探究来自红杆菌Rufibacter hautae NBS58-1的胞外多糖的抗氧化活性及其在草莓保鲜中的应用，采用乙醇沉淀法制备菌株NBS58-1的胞外多糖(EPS-1),利用高效液相色谱和凝胶渗透色谱法分析其单糖组成和分子量，通过自由基清除试验分析其抗氧化活性，测定草莓的质量损失率、可溶性固形物含量、丙二醛含量和抗坏血酸含量以考察EPS-1的保鲜效果。结果表明：EPS-1由葡萄糖、甘露糖、核糖、半乳糖、阿拉伯糖、木糖、半乳糖醛酸、鼠李糖、岩藻糖和葡萄糖醛酸组成，摩尔比为80.33∶11∶2.84∶2.74∶1.79∶0.61∶0.26∶0.17∶0.15∶0.1,分子量为4 652;EPS-1质量浓度为5 mg/mL时，对ABTS、DPPH和羟基自由基的清除率分别为(81.48±2.09)%、(41.47±0.37)%和(91.59±0.73)%,总还原力在700 nm处的吸光度为0.29;在草莓保鲜应用中，EPS-1可减少草莓的质量损失及丙二醛含量，延缓可溶性固形物降解和抗坏血酸氧化。由此可知，红杆菌Rufibacter hautae NBS58-1的胞外多糖EPS-1是一种杂多糖，具有自由基清除活性，可延长草莓保质期。更多还原

【Abstract】 Some microbial exopolysaccharides have efficient antioxidant capacity. In order to investigate the antioxidant activity of exopolysaccharides extracted from Rufibacter hautae NBS58-1 and study its function in strawberry preservation, the exopolysaccharide(EPS-1) from strain NBS58-1 was prepared by ethanol precipitation. The composition and molecular weight of the EPS-1 were analyzed by high performance liquid chromatography(HPLC) and gel permeation chromatography(GPC), the antioxidant activity of EPS-1 was explored by free radical scavenging experiments, and its application in strawberry preservation was explored. The results showed that the EPS-1 was composed of glucose, mannose, ribose, galactose, arabinose, xylose, galacturonic acid, rhamnose, fucose and glucuronic acid with a ratio of 80.33∶ 11∶ 2.84∶ 2.74∶ 1.79∶ 0.61∶ 0.26∶ 0.17∶ 0.15∶ 0.1, and the molecular weight was 4 652. The results of free radical scavenging experiments showed that the antioxidant activity of EPS-1 was positively correlated with its mass concentration in the concentration range of 0-5 mg/mL. At the concentration of 5 mg/mL, the scavenging rates of ABTS, DPPH, and hydroxyl radical were(81.48±2.09)%,(41.47±0.37)%, and(91.59±0.73)%, respectively. The absorption value of total reducing power at 700 nm was 0.29. When EPS-1 was used as a coating solution for strawberries, the mass loss rate of strawberries was(55.58±0.89)% after 7 d, which was smaller than that of the control group. The content of SSC was(7.03±0.12)%, which was significantly higher than that in the control group. The MDA content was 4.07 μmol/L, which was significantly lower than that of the control group. The content of Vc was(23.63±0.67) μg/g, which was significantly higher than that of the control group. These results showed that EPS-1 could reduce the weight loss and malonaldehyde content of strawberry, delay the degradation of soluble solids and Vc oxidation. Therefore, EPS-1 from R. hautae NBS58-1 is a heteropolysaccharide with free radical scavenging activity and can prolong the shelf life of strawberry.更多还原