Effects of microwave extraction on characteristics of polysaccharides from cherry, kiwi and wolfberry

Microwave-assisted extraction (MAE) is a rapidly developing new technology for extracting natural compounds. The effects of MAE on the yield, structure and bioactivity of polysaccharides from cherry, kiwi and wolfberry fruits were investigated. Water-soluble polysaccharides (WSP) from those fruits were extracted by a boiling water procedure (BW) and MAE. The MAE was performed at microwave power of 1 000 W and heating temperature of 140℃. The extraction time was 5, 10 and 20 min, respectively. Results showed that the yield, relative molecular weight and antioxidant activities of WSP extracted by MAE were lower than those extracted by BW. The molecular weight of WSP was decreasing with the increase of microwave extraction time, however, the yield and antioxidant activities of WSP had no significant change when the microwave extraction time increased from 5 min to 20 min. The sugar composition of WSP by MAE was different from that by BW. The results provide usefully references for the extraction of fruit polysaccharides by microwave technique and the polysaccharides quality control during extraction.