摘要
考察不同低聚糖不同浓度对乳杆菌的生长促进作用和常见实验室或生产保藏过程中对乳杆菌的活性保存作用。采用不含葡萄糖的MRS培养基,分别添加0,0.3%,0.6%,1.2%(W/V)浓度的6种低聚糖,接种乳杆菌后测定A630,连续测定42 h并绘制生长曲线进行分析。采用不同处理过程,添加2%或20%低聚糖溶液,测定活菌数目或牛乳-pH变化曲线,考察低聚糖对乳杆菌的活性保存作用。处理过程包括硅胶干燥保存、冷冻保存和冷冻真空干燥保存。活菌计数反映存活菌数,而牛乳-pH曲线反映存活菌的延迟期,间接反映其活性状态。冻干菌粉进一步进行2周的室温保藏,测定菌体失活速率评估低聚糖对冻干菌粉的活性保护作用。针对效果较好的低聚糖,采用LC-MS分析冻干及保藏过程中低聚糖成分的组成和变化。低聚半乳糖、低聚异麦芽糖、低聚木糖和低聚果糖对3种实验菌株生长的支持较好,且表现出浓度效应。1.2%浓度时,低聚半乳糖或低聚异麦芽糖效果最好,接近于含葡萄糖的完全MRS肉汤(葡萄糖2%)。水苏糖和棉籽糖对实验菌株生长支持较差。冷冻保藏时,2%浓度的各种低聚糖具有近似的保护效果,而20%浓度时低聚果糖和低聚木糖表现出更好的保护作用。在干燥保藏和冻干保藏过程中,水苏糖和棉籽糖的保护效果最好,冻干菌粉室温保藏2 w仍能保持较高乳酸菌活菌数。进一步的LC-MS分析表明,水苏糖和棉籽糖在冻干和保存过程中并未进入细胞内部被分解利用,可能通过在胞外提供一个较好的物理保护环境发挥作用。不同低聚糖对乳杆菌生长促进效果不同,1.2%低聚半乳糖或低聚异麦芽糖对实验乳杆菌支持效果最优。保藏益生菌时,可根据不同的保藏手段,合理选择低聚糖,达到较好的活性保存效果。
To investigate the growth-promoting effect and activity preservation effect of oligosaccharides on Lactobacillus,different concentrations of the six oligosaccharides,i. e.,0,0. 3%,0. 6%,and 1. 2%（ W /V）,were added to MRS medium without glucose.Strains of Lactobacillus were inoculated into the mMRS-oligosaccharide medium and A630 was measured continuously for 42 h to obtain growth curves. Oligosaccharides of 2% or 20% were tested for the protective effects on Lactobacillus during various treatments,including silica gel desiccation,freezing,and freeze-drying. Viable cells counts and pH value curves in milk were determined to show the viability and activity of remaining cells. Freeze-dried powder was stored for two weeks at room temperature and the dying rate was measured. LC-MS was used to analyze the composition and changes of oligosaccharides during the freeze-drying and preservation period. Results showed that galacto-oligosaccharide,isomalto-oligosaccharide,xylo-oligosaccharide and fructo-oligosaccharide supported the growth of tested strains better than other oligosaccharides. At the concentration of 1. 2%,galacto-oligosaccharide and isomalto-oligosaccharide had the best effect on supporting Lactobacillus growth and achieved a similar effect to that of glucose,whereas raffinose and stachyose performed the worst. All tested oligosaccharides with a concentration of 2% protected Lactobacillus well in freezing storage. With a concentration of 20%,fructo-oligosaccharide and xylo-oligosaccharid showed a better protective effect than that of others. In the silica gel desiccation and freeze-drying preservation tests,raffinose and stachyose performed the best. After 2 weeks storage at room temperature,viable counts remained high in freeze-dried form with raffinose or stachyose. Further LC-MS analysis showed that raffinose or stachyose was not absorbed into cells and degraded in the freeze-drying storage,indicating an extracellular physical protecting mechanism. Various growth-promoting effects of different oligosac
出处
《药物生物技术》
CAS
2014年第4期338-342,共5页
Pharmaceutical Biotechnology
关键词
低聚糖
益生素
冻干
保藏
乳杆菌
液质联用
01igosaccharide, Prebiotics, Freeze-drying, Preservation, Lactobacillus, LC-MS
