Abstract:

The polysaccharides from the bark of Eucommia ulmoides Oliver. were extracted by ultrasonic-assisted extraction. With the extraction rate of polysaccharides as the evaluation index, on the basis of single factor experiment, the extraction process of polysaccharides from the bark ofEucommia ulmoides Oliver. was optimized by orthogonal test; with the decolorization rate and the retention rate of polysaccharides as the evaluation indexes, the process of removing pigment in the polysaccharides extracted from the bark of Eucommia ulmoides Oliver. by activated carbon was optimized by orthogonal test. The results showed the optimum extraction technology of polysaccharides from the bark of Eucommia ulmoides Oliver., in which the liquid-solid ratio was 30∶1（mL∶g）, the ultrasonic temperature was 50 ℃, the ultrasonic power was 400 W, and the ultrasonic time was 30 min. Under these conditions, the average extraction rate of polysaccharides from the bark of Eucommia ulmoides Oliver. is 2.16%, and the relative standard deviation（RSD）is 1.86%. The optimum conditions for decolorization of polysaccharides from the bark of Eucommia ulmoides Oliver. by activated carbon method are as follows: the dosage of activated carbon is 0.60%（m/m）, the decolorization temperature is 60 ℃, the decolorization time is 50 min, and the pH of decolorization solution is 5.0. Under these conditions, the average decolorization rate is 76.20%, and the RSD is 2.46%; the average retention rate of polysaccharides is 62.68%, and the RSD is 2.35%.

Key words: bark of Eucommia ulmoides Oliver., polysaccharide, ultrasonic, extraction, depigmentation