Optimization of Ultrasonic/Microwave-Assisted Extraction of Polysaccharides from Green Tea by Response Surface Methodology

Response surface methodology was used to optimize the ultrasonic/microwave-assisted extraction of water-soluble polysaccharides from crude green tea.The traditional water extraction and ultrasonic/microwave-assisted extraction methods were compared for their effect on extraction efficiency,purity and structure of polysaccharides.The optimal ultrasonic-assisted extraction conditions were extraction time of 23 min,material-to-liquid ratio of 1:30(g/mL) and microwave power of 90 W.The ultrasonic/microwave-assisted extraction method required shorter time and increased polysaccharide yield from 2.95% to 4.19% and polysaccharide purity from 70.15% to 86.08% compared with the traditional water extraction method.Polysaccharides extracted by the methods had basically the same groups.