Study On The Extration, Isolation, Purification, Antioxidant Activity Of Polysaccharides From Barley Malt Roots

Barley malt roots are fibrous roots of malt, slender and curved. Barley malt roots as a by-product of beer industry account for about 3% of total feed. Barley malt roots contain amino acids, proteins, carbohydrates, vitamins and minerals and other elements and nutrients. At present, Barley malt roots mainly used as feed all over the world. In this paper, barley malt roots as a raw material were systematic studied on the aspect of basic nutritional component, optimization of extraction of polysaccharides from malt roots, separation, purification, physical and chemical properties, primary structure and biological activity. The results are as follows:Method of water extraction and alcohol precipitation was used for extracting water-soluble polysaccharide from malt roots. Orthogonal experiment based on the single factor experiments which were extraction temperature, extraction time and ratio of solid to liquid, on extraction rate of polysaccharides of malt roots. The optimum extraction parameters:liquid ratio 40:1 (V/W), temperature 90℃,extraction three times, time 2 hours.The polysaccharides of malt roots BCP30, BCP50, BCP80were obtained by water extract, protein removal, decolorization, precipitation and refined with different concentration of ethanol. BCP80 was obtained after diethylamino ethyl (DEAE) cellulose column chromatography. Using 0 to 1.0 mol/L NaCl solution, elution, three fractions BCPⅠ,BCPⅡ,BCPⅢwere obtained. The three fractions were concentrated and freeze-dried, white powder were obtained. BCPⅡpurified by Sephadex G-100 column chromatography was obtained two symmetrical peaks BCPⅡa, BCPⅡb. BCPⅢpurified by Sephadex G-100 column chromatography was obtained a fraction named as BCPⅢa. By paper chromatography, cellulose acetate membrane electrophoresis and optical rotation, BCPⅡa, BCPⅡb and BCPⅢa were homogeneous fractions, respectively.BCPⅡa, BCPⅡb, BCPⅢa are white powdery solid, soluble in water, dilute acid and alkali, insoluble in ethanol, acetone and other organic solvents. Phenol-sulfuric acid reaction was positive, negative Fehling reagent, Coomassie brilliant blue staining reaction was negative, iodine-potassium iodide reaction was negative, Molish positive for reaction, ferric chloride reaction was negative. Results show that the three fractions of polysaccharide are of non-reducing, non-polyphenol, protein-free polysaccharide. UV, IR and 1H-NMR analysis, the three fractions of polysaccharide areβ-glycosidic linkage of the pyran ring polysaccharide. Rotary steam condensed by water extraction and alcohol precipitation of polysaccharide extracted and purified with 50% and 80% ethanol were two separate sub-analysis of alcohol polysaccharides BCP50 and BCP80,Spectrophotometry of the two polysaccharides in different systems on the hydroxyl radical, superoxide, DPPH radical scavenging, reducing power and lipid oxidation determined with the methord of Rancimat with witch antioxidant activity were measured.The results show that the polysaccharides separated and purified from malt roots are beta glycosidic bond pyranoid ring polysaccharide. There exists antioxidant activity for malt extract extracted at optimization being water-soluble polysaccharide. And more, malt polysaccharide antioxidant activity offers the base for further studies of immune activity, antitumour, antimutation, antiviral. Therefore, the research on active, polysaccharides especially malt plays an important role and broad application prospect.