Abstract: To develop the resource of Cyclocarya paliurus polysaccharides (CPP),ultrasonic and enzyme-assisted extraction of CPP was optimized and its structure was preliminarily studied.Firstly,the optimum range of each single factor was identified by single factor experiment.Then,the key factors affecting the yield of CPP were screened with Plackett-Burman design,and the extraction of CPP was optimized with Box-Behnken experiment.Finally,UV,FTIR spectra and gas chromatograms were employed to preliminarily identify the structure of CPP.Results indicated that the key factors were pH,amount of mixed enzyme,enzymatic time and ultrasonic power.In addition,the optimal extraction conditions were pH of 6.11,amount of mixed enzyme of 4.81%,enzymatic time of 1.685 h,ultrasonic power of 96.9 W,solid to liquid ratio of 1:20,and ultrasonic time of 30 min.Under these conditions,the extraction yield of CPP was 7.18%.CPP was a typical polysaccharide and the monosaccharide composition was consisted of rhamnose,arabinose,xylose,mannose,glucose,galactose,with a molar ratio of 1.00: 7.03: 2.06: 2.11: 5.25: 12.06.

Key words: Cyclocarya paliurus polysaccharides, ultrasonic, mixed enzyme, Plackett-Burman experiment, Box-Behnken experiment, monosaccharide composition