乳酸菌联合酿酒酵母发酵对龙须菜多糖结构特征及抗氧化性的影响

Effects of Lactobacillus and Saccharomyces cerevisiae Fermentation on Structure Characteristics and Antioxidant Properties of Gracilaria lemaneiforms Polysaccharide

为明确微生物发酵对龙须菜浆液多糖体外抗氧化活性的改善效果,以期为龙须菜的高值化利用提供理论参考。采用乳酸菌副干酪乳杆菌亚种RP38与酿酒酵母JJ4复合发酵龙须菜浆液,利用色谱及光谱分析技术解析了龙须菜多糖的结构变化,考察了发酵前后浆液多糖的自由基清除能力。研究结果表明,龙须菜经发酵后浆液多糖质量分数由0.30%提高至0.79%,其中硫酸酯多糖质量分数由0.03%提高至0.12%。多糖的凝胶渗透色谱及红外光谱研究结果表明,微生物发酵不改变龙须菜多糖的官能基团,但可降解龙须菜多糖分子质量,进而使其结构暴露出更多的硫酸酯基团。核磁共振扫描发现,硫酸酯多糖的硫酸酯主要分布在半乳糖的C-6位,微生物发酵并不改变硫酸酯在糖链上的分布位置,但可以提高硫酸酯的含量。进一步研究发现,发酵后的龙须菜浆液多糖的羟自由基清除能力提高了5.33%,超氧阴离子自由基清除能力提高了32.12%。龙须菜浆液发酵后多糖抗氧化活性提高可能与生成更强给氢能力的小分子多糖以及硫酸酯基团暴露量增多有关。

The improvement effect of microbial fermentation on in vitro antioxidant properties of Gracilaria lemaneiforms slurry polysaccharide was studied to provide theoretical support for high value utilization of Gracilaria lemaneiforms.The structure changes of polysaccharide before and after fermentation by Lactobacillus RP38 and Saccharomyces cerevisiae JJ4 were analyzed by modern chromatography and spectral analysis techniques.The free radical scavenging ability of slurry polysaccharides before and after fermentation was investigated.The result showed that the mass fraction of polysaccharide increased from 0.30%to 0.79%,and sulfated polysaccharide mass fraction increased from 0.03%to 0.12%.Results of gel permeation chromatography and infrared spectroscopy revealed that functional groups of Gracilaria lemaneiforms polysaccharides remained unchanged after biological fermentation,the molecular weight of the polysaccharide was reduced,and then more sulfate groups exposed.In addition,it was found by nuclear magnetic resonance scanning that sulfate group of sulfated polysaccharide was mainly distributed in the C-6 position of galactose.The distribution position of sulfate was not changed by biological fermentation,but the content of sulfate was improved.The hydroxyl radical scavenging ability of Gracilaria lemaneiforms polysaccharide was increased by 5.33%and the superoxide radical scavenging ability was increased by 32.12%after fermentation.In conclusion,the antioxidant properties of Gracilaria lemaneiforms slurry could be improved by Lactobacillus RP38 and Saccharomyces cerevisiae JJ4,which may be related to the fact that the formation of small molecular polysaccharide with hydrogen supply capacity and more sulfate groups exposure during fermentation.