Optimized technology for microwave-aqua extraction and purification of Amomum villosum L. polysaccharides

For utilizing the different effective components in Amomum villosum L. compositively, three-grade of microwave extractions were designed. The impurities in the sample were removed, while the flavor and taste ones were reclaimed at the same time, and then Amomum villosum L. polysaccharides were gained by microwave-aqua extraction. In the process, the previous gentle extraction protected the trait of the later products. The experiment procedure is that the lower polarity chemical components in Amomum villosum L. were removed by ether; followed by raising the polarity of solvents, the middle polarity ones were removed by 95% ethanol, and then polysaccharides was extracted by aqua. The single factor and orthogonal experiments were carried on to choose the best technics for extracting the polysaccharides. Results are as follows: solvent/solid ratio 10∶1(V/W); microwave power 600 W; time 20 min, and the corresponding yield of Amomum villosum L. polysaccharides is 11.33%; the conditions of purifying the polysaccharides: the proportion of CHCl₃ and n-butanol in Sevag reagent is 3∶1; the time of extraction is 3; the yield of the purified polysaccharide is 50.30%; the dry conditions: temperature -49～-56℃; pressure 24～40 kPa and time 4 h.