以泽兰为原料,利用微生物发酵法制备种新型的α-低聚半乳糖,其组成包括蜜二糖、半乳三糖、半乳四糖和半乳五糖等。实验通过Plackett-Burman设计从6个因素中筛选出了有显著影响的发酵温度、初始糖浓度、酵母膏和KH2PO44个因素;通过陡爬坡试验和Box-Behnke设计进步优化,并利用Design-Expert软件进行回归分析,得到以上4个因素的优条件分别为:发酵温度28℃,初始糖浓度8.76°Brix,酵母膏1.2 g/100mL,KH2PO40.21 g/100 mL。采用优化后的发酵条件,α-低聚半乳糖含量由86%提高到94%。

A new type of α-galactooligosaccharide( α-GOS) by microbial fermentation from herba lycopi was studied.Its componet includes melibiose,trisaccharide,tetrasccharide and pentosaccharide.By Plackett-Burman design and response surface methodology,the optimization of preparation α-GOS by fermentation was carried on.A Plackett-Burman design was first used to evaluate the influence of six related factors,and fermentation temperature, concentration of initial sugar,yeast extract and KH 2 PO 4 were selected as the important factors.Steepest ascent experiment and Box-Behnke design were used for further optimization on these factors.By establishing the regression model equation,the optimal concentration of these variables were determined as: fermentation temperature 28℃,concentration of initial sugar 8.76° BX,yeast extract 1.2g /100ml,KH 2 PO 4 0.21g /100ml.Under the above optimal culture conditions,the concentration of α-GOS increased from 86% to 94%.