Abstract: The ultrasonic pretreatment followed by hot water treatment was investigated to establish a method to extract polysaccharide from Toddalia asiatica. Effects of operation conditions on polysaccharide yield, such as ultrasonic power, extracting time, temperature and the ratio between material and water were studied by single factor experiment and orthogonal test. The result showed that the optimal extraction technology of polysaccharides was the ratio between water and material 15:1 (mL:g), pretreatment by 250 W ultrasound for 25 min, then was of the traditional water extraction at temperature 55℃ for 2 h. The polysaccharide yield was 2.18%. Compared with traditional water extraction, the polysaccharide yield was improved by 66.4% under the ultrasonic-pretreated extraction.

Key words: Toddalia asiatica, polysaccharides, ultrasonic pretreatment