Study On Extraction And Hydrolysates Of Lycium Barbarum Polysaccharides

With so many good curative effect on the immune regulation, anti-tumor, anti-virusand so on, plant polysaccharides is widely used in health care products, food, cosmetics,medical supplicatin. But macromolecular polysaccharides was poorly water-soluble, toa certain extent affects the absorption of it. In recent years, studies found plantpolysaccharides hydrolysate with smaller molecular weight, solubility and permeabilitycan be improved to some extent, can compensate for the defects of low utilization rateof macromolecular polysaccharides, also showed good biological activity. In this paper,dried wolfberry was used as raw materials. The response surface analysis method wasused to study the extraction process of Lycium barbarum polysaccharide andhydrolyzed LBP by acid hydrolysis method, the degree of hydrolysis and anoxidationability of the hydrolyzate were researched. Then ultrafiltration membrane separationtechnology was used to separate hydrolyzate and oxidation resistance was comparedafter seperation, finally the hydrolysate was purified and a preliminary structural studywas made. The main fingdings are as follows:1. Hot water extraction method was used to extract LBP, Box-Behnkenexperimental design was implemented based on single-factor test. At last the optimumprocess conditions of extraction LBP was determined: the material liquid ratio was1∶27, extraction temperature was81℃, the extraction time was2.5h, the yeild of LBPcan be as high as5.03%.2. The hydrolysis technology of LBP was studied and the degree of hydrolysis andanoxidation ability in vitro of the hydrolyzate was used as index by L9(33) orthogonalexperimental design to optimize the parameters of acid concentration, reactiontemperature and reaction time, the test results were analyzed using comprehensivebalance multi-index, the result showed that the optimal concentration of hydrochloricacid in the process of hydrolysis was2mol/L, hydrolysis temperature was90℃, thereaction time was5h, and the verification test showed that under this condition, thedegree of hydrolysis was85.50%, the reducing power absorption value of hydrolysatewas0.465, free radical clearance rate of hydroxyl radicals, DPPH and superoxide anionrespectively was47.06%,96.31%,23.29%.3. The ultra-filtration method was used to separate LBP hydrolyzate based onmolecular weight, receiving Mw>10KDa,5KDa<Mw<10KDa,3KDa<Mw<5KDa,Mw<3KDa this four kinds of molecular weight segment, and a comparision of theiroxidation resistance in vitro was studied, the results showed that the molecular weight was closely related to the antioxidant, the Mw<3KDa part haved the highest antioxidantactivity, however the highest molecular weight portion and the component withintermediate range of molecular weight haved the smaller antioxidant activity, so thecomponent with the smallest molecular weight was choosed for further analysis.4. Using DEAE-52cellulose anionic column for simple separation and purificationof the smallest molecular weight part to get A and B two substances, IR and GC/MSanalysis was infrared. The results showed A substance was mainly composed of glucose,MS spectrum showed the possibility of A substance was2,3,4,5,6-Penta-O-acetyl-D-gluconitrile; MS spectrum showed the the possibility of Bsubstance was composed of à-D-Galactopyranoside,methyl-2,3,6-tri-O-acetyl-4-O-octyl-、d-Mannitol, pentaacetyl-1-O-propyl-、d-Mannitol,1,4-anhydro-,tetraacetate,3-Desoxy-3-acetoxymethyl-1,7-diacetyl-2,5:4,6-dimethylene-d-glycero-d-mannito, indicated B substance contained mannose andgalactose.