益生菌植物乳杆菌G1-28复合冻干发酵剂制备及保藏条件研究

为延长益生菌菌种的保藏时间，提高细胞存活率，以具有体外降胆固醇降甘油三酯功能的植物乳杆菌G1-28为菌种，对离心条件、冻干发酵保护剂配方及保藏条件进行了研究和优化。以活细胞收集率为指标，研究了菌悬液离心转速和时间对细胞收集率的影响；通过单因素实验及正交试验优化了植物乳杆菌的冻干保护剂并以存活率为指标，研究了真空条件和保藏温度对植物乳杆菌G1-28冻干发酵剂保藏效果的影响。结果表明，植物乳杆菌G1-28菌悬液的离心收集条件为5000 r/min，20 min，在此条件下活细胞收集率为96.26%；在脱脂乳7%，海藻糖2%，山梨醇3%，甘油4%条件下，细胞存活率最大为93.20%；最佳保藏条件为抽真空条件下?20 ℃保藏，保藏4个月后其存活率为97.1%，研究结果可为植物乳杆菌G1-28益生菌发酵剂的制备及降胆固醇降甘油三酯功能性食品的开发奠定基础。

Preparation and Preservation Technology of Probiotic Lactobacillus plantarum G1-28 Composite Lyophilized Starter

In order to prolong the preservation time of probiotic bacteria and improve the cell survival rate, the conditions of centrifugation, formulation and preservation of lyophilized fermentation protection agent werestudied and optimized with Lactobacillus plantarum G1-28, which has the function of lowering cholesterol and triglyceride in vitro. Effects of centrifugal speed and time on cell collection rate of bacterial suspension were studied by living cell collection rate. And the effects of vacuum conditions and preservation temperature on the preservation effect of Lactobacillus plantarum G1-28 lyophilized starter were studied by single factor test and orthogonal test. The experimental results showed that the centrifugal collection condition of Lactobacillus plantarum G1-28 suspension was 5000 r/min and 20 min, and the collection rate of live cells was 96.26%. The cell survival rate could reach 93.20% under this condition of skim milk 7%, trehalose 2%, sorbitol 3%, glycerol 4%. The best preservation condition was ?20 ℃ under vacuum condition, and the survival rate was 97.1% after 4 months. As a result, the research could lay a foundation for the preparation of Lactobacillus plantarum G1-28 probiotic starter and the development of cholesterol-lowering triglyceride functional food.