Extraction, Purification And Structure Analysis Of Polysaccharides From Peanut Meal

Cold-pressed peanut meal is a by-product of the cold pressed peanut oil, with good function characteristic and high utilization value. Peanut polysaccharide (PPS) is one of the main active ingredients of the peanut meal, with the function of anti-oxidant, hypoglycemic and liver injury protection, so the extraction and research on peanut polysaccharides has practical significance. This subject adopt cold pressed peanut meal as the research object, then discuss the technology of high temperature and high pressure extracting peanut polysaccharides and research the technique of purification and primary structure. The main content of this research and conclusions are summarized as follows:1. Through the single factor experiment investigated the extraction temperature, pH, extraction time and solid-liquid ratio effect on the yield of polysaccharide, on the basis of Box-Behnken optimization design test, established a peanut polysaccharides extraction of two degree polynomial regression model, through the response surface analysis of peanut polysaccharides optimization the optimal extraction conditions: extraction temperature 118℃, pH 2.5, extraction time 65min and solid-liquid ratio1:20. The yield of polysaccharide peanut is 9.91% in this experiment condition, which is very close to the predictive value, which indicates that the two multinomial regression equation can well simulate the extraction conditions of experiment. The component analysis of peanut crude polysaccharide which extracted depend on this method indicates that the fat, protein and ash content in crude polysaccharide is low, but the starch content has a high proportion 27.58%, we need to study its removal method.2. Study the purification process of peanut polysaccharide starch enzyme to lift, and removal of protein. The optimizing technological conditions of thermostable alpha-amylase enzyme is enzyme amount 4%, pH 6.5, temperature 100℃, time 20minutes, in this condition the DE value is 18.86%. And the optimizing technological conditions of glucoamylase is enzyme amount 2.0%, pH 4.5, temperature 60℃, time 2 hours, in this condition the DE value is 95.65%. The peanut polysaccharide we get after using enzymes to remove starch does not contain starch, and the purity of polysaccharide increases from 51.76% to 78.87%. Papain-TCA method can achieve the effective removal of protein in the crude polysaccharides purpose.3. Study the purification process of peanut polysaccharide column chromatography classification. By DEAE-52 cellulose ion exchange column chromatography purification of peanut polysaccharide, first distilled water elution and then 0-0.3mol/L NaCl linear gradient elution, all peanut polysaccharide in 0.223 mol/L NaCl concentration are eluted from the column, and two major polysaccharide polysaccharide PPS-1 and acidic polysaccharides PPS-2, these two polysaccharide by Sephadex G-200 column chromatography, the experimental results can initially determine the PPS-1 and the PPS-2 are relatively simple polysaccharide, which indicates that on DEAE-52 cellulose ion exchange chromatography can better achieve the separation of the different peanut polysaccharide.4. The purity identification and color reaction of the peanut polysaccharides showed that PPS-2 is a non-starch polysaccharide which combined without protein. It is composed of rhamnose, fucose, arabinose, xylose, glucose and galactose in a molar ratio of 1.61:0.14:7.54:2.4:0.25:1 by Gas chromatography analysis. Its molecular weight Mw is 8.77×105 determined by HPGPC. It is showed that the PPS-2 is a type pyranoid ring polysaccharide by the structure analysis of UV, IR and NMR.