Study On Preparation Of Water-soluble Sugars From Volvariella Volvacea And Their Probiotic Effects

In this paper, extraction, purification and prebiotic effects of polysaccharides and oligosaccharides from fruit body of Volvariella volvacea were investigated. The results are as follows:The contents of dominant components of Volvariella volvacea were determined. The results showed that protein, crude fat, crude polysaccharides, total saccharides, reducing sugars and ash in fruit body of Volvariella volvacea were33.18%,2.04%,39.42%,7.14%,9.86%and7.09%, respectively. Orthogonal test were applied to optimize the extracting of total saccharides from Volvariella volvacea. The optimal conditions were as follows:solid-to-liquid ratio1:30, temperature at50℃, extracting time for2hours, continual extraction2times. The yield of total water-soluble was29.8%。Volvariella volvacea polysaccharides were isolated by alcohol precipitation. The deproteinization and decolorization methods were compared. The best method for removal of protein is Sevag method combined with Papain. With this method, deproteinized rate was95.3%and polysaccharide loss rate was10.08%. Deproteinized polysaccharide solution was decolorized by activated carbon and the optimal conditions as follows:activated carbon dosage1.5%, temperature at70℃, decolorizing30minutes. Under this condition, the decolorization rate was76.12%and polysaccharides retention rate was80.03%. After dialysis and drying, light yellow straw mushroom polysaccharide with different molecular weight was obtained.The supernatant after alcohol precipitation for separation of polysaccharide were mixed with oligosaccharides and monosaccharides. The monosaccharides and fermentable oligosaccharides could be removed by yeast fermentation for48h, and the unfermentable oligosaccharides were mainly composed of trehalose. After depletion of yeast by centrifuge, fermented both were decolorized by D101macroporous resins and activated carbon, and then purified by ion-exchange resin to give refined oligosaccharides.The prebiotic effects in vitro of Volvariella volvacea oligosaccharides and polysaccharides showed that Volvariella volvacea polysaccharide significant induced the proliferation of bifidobacteria and lactobacilli, while the oligosaccharides had no obvious effect on these two bacteria.