Abstract: Five cultivars of Chinese jujube were analyzed to compare their chemical components. Results of tests showed that Ziziphus jujuba cv. (Jinsixiaozao)had higher content of soluble fiber and lower contents of protein and ash. The ultrasonically assisted extraction conditions of polysaccharides from Z. jujuba cv. were studied. Method of response surface regression was used to optimize the extraction under various conditions for the optimum yield and purity of polysaccharides. Analysis showed that yield and purity changed substantially with changes of extraction temperature and ultrasonic power. Optimum extraction conditions were identified to be temperature 45 to 53℃, ultrasonic power 86 to 96 W, time 20 min, stock ratio 1:20 (g:mL). FT-IR spectra analysis indicated that structural characteristics of the extractives obtained under ultrasonically assisted extraction were almost identical to those from the traditional method.

Key words: ultrasonically assisted extraction, Ziziphus jujuba cv., Chinese jujube polysaccharides