Abstract:

The microwave-assisted extraction of polysaccharide from dried burdock root powder below 40 mesh was separately performed under normal atmospheric and closed high pressures. One-factor-at-a-time and L9(34) orthogonal array methods were employed for optimizing two extraction procedures of polysaccharide from burdock roots. Maximum polysaccharide yields of 28.84% and 31.97% were obtained by extraction for 100 s at 250 W microwave power and normal pressure with a material/water ratio of 1:25 and by extraction for 160 s at 90 W microwave power and 0.4 MPa pressure with a material/water ratio of 1:35, respectively, both of which were higher than the yield of 24.18% by hot water reflux extraction for 6 h. All these results indicate that microwave-assisted extraction is a simple and rapid method, and microwave extraction combined with high pressure technology is more efficient.

Key words: atmospheric pressure microwave, high pressure microwave, burdock, polysaccharide, extraction