响应面法优化产朊假丝酵母培养及干燥工艺

本研究旨在优化产朊假丝酵母液体培养参数及干燥保护剂配方,提高产朊假丝酵母液体培养数量,制备出高复苏率的活性干酵母。以装液量、转速、温度和培养时间为影响因素,设计单因素试验,并采用Box-Behnken试验设计及响应面分析法优化产朊假丝酵母液体培养方案。在此条件下培养酵母,以L-谷氨酸钠、乳糖、脱脂奶粉为影响因素进行单因素保护试验,并采用响应面分析法优化干燥保护剂的组合。结果表明,产朊假丝酵母最佳培养条件为装液量45 mL/250 m L,转速200 r/min,温度30℃,培养时间24 h。在此条件下,培养的产朊假丝酵母数量可以达到9.34×10~8CFU/mL;最佳保护剂组合1%L-谷氨酸钠、12%脱脂奶粉、6%乳糖,经干燥后,产朊假丝酵母复苏率达到81.9%。此时活菌数7.65×10~8CFU/g,比未加保护剂组提高了3.83倍。

Optimization of Culture and Drying Process in Candida utilis by Response Surface Methodology

This study aimed to optimize the liquid culture parameters of Candida utilis and the formulation of drying protective agent, improving the quantity of liquid culture in Candida utilis and making preparation of active dry yeast with high recovery rate. The single-factor experiment was designed with the influence factors of liquid volume, speed, temperature and culture time, and the box-behnken test design and response surface analysis were used to optimize the liquid culture of Candida utilis. On the basic of these conditions, the yeast was cultured and the single factor protection test was carried out with sodium L-glutamate, lactose and skimmed milk powder as the influential factors, and the combination of dry protective agent was optimized by response surface analysis. The results showed that the best culture conditions of Candida utilis for the liquid volume 45 m L/250 mL, speed 200 r/min, temperature 30℃, culture time 24 h. In this condition, the number of Candida utilis could reach 9.34×10~8 CFU/mL;The optimal combination of dry protective agent was 1% sodium L-glutamate,12% skimmed milk powder and 6% lactose. After drying, the cell recovery rate of Candida utilis reached81.9%. At this time, the number of viable cells was 7.65×10~8 CFU/g, which was 3.83 times higher than that of the unprotected group.