重结晶法分离甜菊糖的工艺研究

Separation of steviosides by recrystallization

采用甲醇/异丙醇混合溶剂对甜菊糖进行重结晶,以结晶中甜菊甙与莱鲍迪甙A的含量比(S/RA)为主要指标,并综合结晶率,考察结晶溶剂、溶剂用量、结晶温度以及结晶时间的影响。通过正交试验得到重结晶法分离甜菊糖的最佳工艺为:混合溶剂中异丙醇含量30%,溶液初始浓度40%,结晶温度-5℃,结晶时间12h,结晶中S/RA由原料中的0.96提高到3.30。对重结晶的母液在15℃进行二次结晶,结晶中S/RA仅为0.072。

Stevioside （S） and rebaudioside A （RA） was separated by recrystallization using methanol/isopropanol as solvent. The effects of key operation parameters, including solvents, concentration of steviosides, temperature and crystallization time, on the ratio of Stn RA in the crystal product were studied. Under the optimized conditions, namely, methanol ： isopropanol= 70 ： 30 （V： V）, initial concentration 40%, crystallization temperature 5 ℃, crystallization time 12 h, S/RA increased from 0.96 in raw material to 3.30 in the crystal. Then the mother liquor was crystallized at 15 ℃ for second time, and S/RA was 0. 072.