高活菌数干酪乳杆菌LZ183E冻干保护剂的制备

Preparation of Lactobacillus casei LZ183E lyoprotectant with high viable cell count

在高密度培养的基础上,以干酪乳杆菌LZ183E为研究对象,菌株存活率和菌剂产酸能力为响应指标,通过单因素试验考察4种保护剂(海藻糖、低聚木糖、脱脂乳粉和谷氨酸钠)用量对菌株活力的影响;在此基础上采用响应面法对保护剂进行复配优化,并对最优条件下的菌剂的活力和产酸能力作出评价。结果表明,海藻糖、低聚木糖、脱脂乳粉以及谷氨酸钠对干酪乳杆菌LZ183E在冻干过程中有明显的保护效果,并且其最佳复配参数为海藻糖用量6.0%、低聚木糖用量8.5%、脱脂乳粉用量11.5%和谷氨酸钠用量1.0%(均为质量分数)。此条件菌株存活率为(98.236±0.137)%,显著高于未加保护剂的菌剂的存活率(79.241±0.382)%。

Based on high-density culture,Lactobacillus casei LZ183E was used as the research object,the survival rate and the acid production capacity of the strain were taken as response indicators,and effect of the amount of four protective agents(trehalose,xylooligosaccharides,skimmed milk powder and sodium glutamate)on the viability of the strain was investigated through single factor test.On this basis,response surface method was used to optimize the protective agent,and evaluate the vitality and acid production capacity of the bacteria under the optimal conditions.The results showed that trehalose,xylooligosaccharides,skimmed milk powder and sodium glutamate had a significant protective effect on L.casei LZ183E during the freeze-drying process,and the optimal compounding parameters were,ω(trehalose)6.0%,ω(xylooligosaccharide)8.5%,ω(skim milk powder)11.5%,ω(sodium glutamate)1.0%.Under this condition,the survival rate of this strain was(98.236±0.137)%,which was significantly higher than that of the unprotected bacteria(79.241±0.382)%.