为提高酵母冻干存活率，以酿酒酵母为研究对象，菌株存活率为相应指标。冻干保护剂以燕麦β-葡聚糖为主，并与γ-聚谷氨酸和甘露醇复合；采用单因素轮换试验确定3因素的水平并作为响应面优化试验的中心点，进一步利用Central Composite响应面法优化设计试验建立酵母存活率与3因素之间的回归方程；通过响应面分析各个因素对响应值的效应关系，并采用扫描电子显微镜观察冻干后酵母细胞形态。结果表明，保护剂最佳配比为：燕麦β-葡聚糖6.56%、γ-聚谷氨酸0.15%、甘露醇1.15%，菌体与保护剂质量比为1:2混合时，此条件下菌体细胞存活率可达到90.69%，与理论预测值89.86%接近；与未添加保护剂组酵母细胞相比，添加保护剂组酵母细胞形态饱满、结构完整。研究结果可为酵母的冷冻干燥保护及推广应用提供数据支撑。

To improve the survival rate of freeze-dried yeast, Saccharomyces cerevisiae was selected as the research object, and the survival rate of the strain was the corresponding index. The main freeze-dried cryoprotector was oat β-glucan, which was combined with γ-poly-glutamic acid and mannitol. The single factor rotation test was used to determine the level of three factors and serve as the central point of response surface optimization test. The regression equation between the survival rate of yeast and the three factors was established by Central Composite response surface method. The effects of various factors on the response values were analyzed by response surface analysis, and the morphology of lyophilized yeast cells was observed by scanning electron microscope. The results showed that the best ratio of cryoprotectores was 6.56% oat β-glucan, 0.15% γ-poly-glutamic acid, 1.15% mannitol, and the mass ratio of bacteria to protective agent was 1:2. Under these conditions, the survival rate of cells could reach 90.69%, which was close to the theoretical predicted value of 89.86%. Compared with the yeast cells without adding cryoprotector, the yeast cells in the group with adding cryoprotector were full in morphology and complete in structure. The results of this study can provide data support for the freeze-drying protection and promotion of yeast.

国家自然科学基金项目（31601506）；河南省科技攻关项目（192102110100；182102110320）