Extraction and Purification of Water-soluble Carbohydrates from the Fruit Body of Grifola frondosa

Grifola frondosa contains abundant carbohydrates. Oligosaccharides and polysaccharides were extracted with different temperatures for the research of the types and contents of water-soluble carbohydrates in G. frondosa. Oligosaccharides were isolated and purified, extracted at a low temperature of 30℃. The structure of oligosaccharide was identified by Nuclear magnetic resonance. A single substance was filtered through the Sephadex G-25 gel after desalting and decoloring. The structural identification results showed that the substance was trehalose with a content of 10.89% (dry weight). The carbohydrate content in the slag phase obtained by centrifugation was still very high (about 30%) after extraction at 30℃. In order to make full use of G. frondosa material, the slag phase, treated by low temperature (30℃), was used to extract polysaccharides at 130℃ and alcohol precipitation, The yield of polysaccharides extracted at high temperature was 3.42% (dry weight), and two polysaccharides were separated by Sephadex G-75 gel filtration, whose relative molecular mass was 300 kDa and 16 kDa, respectively. The surface structure of the raw material and slag (130℃) was observed by scanning electron microscope. The three-dimensional image of the material was obtained quickly and effectively to observe the surface modification of the material. The results showed that compared with the original sample, the residue of G. frondosa treated at high temperature was loose and porous, which reflected the position of soluble carbohydrates in G. frondosa obviously.