Abstract: Fresh ginger was used as materials in this study. The optimal extractional conditions of the polysaccharide were researched by orthogonal test using temperature, time and ratios of ginger to water as testing parameters. The methods of deprotein of ginger polysaccharide extract were compared among trichloroacetic acid method, digallic acid method and Sevag method. The results showed that: the optimal conditions of ginger polysaccharide extraction are 60 ℃ of temperature, 1:10 of ratios of ginger to water and 3 h of extracting times, the extracting ratio is 20.43%±0.23% under these conditions. The digallic acid method is more suited to remove protein from gigner polysaccharide extracts, the purity of obtained the polysaccharide after deprotein is 73.11%±0.05%.

Key words: ginger, polysaccharide, extraction, deprotein