ABSTRACT
Objective To development a cooling crystallization process that is suitable for industrial preparation of purified dihydromyricetin.Methods Screen design was used to investigate effects of process parameters such as,temperature,concentration ethanol aqueous,quantity of activated charcoal and adsorption time on yield and purity of dihydromyricetin.Purity was verified by high performance liquid chromatography and thin layer chromatography.The solubility of dihydromyricetin in water at viable temperature and ethanol proportion was also determined by UV spectrophotometry.The solid form was characterized by thermal analysis and powder X-ray diffractometry.Results When temperature was ＞ 85 ℃,ethanol concentration ＜ 10％,dosage of activated charcoal 0.1％-0.3％,and adsorption time 1-3 min,yield of dihydromyricetin was more than 70％,and the purity greater than 98％.The crystals,prepared by cooling crystallization from water and ethanol aqueous,had the same physical form and crystal habit.Conclusion Cooling crystallization from low concentration of ethanol aqueous gets higher yield and the process is more robust than crystallization from water.