Study On The Extraction,Purification,Structure Analysis And Application Of The Polysaccharide In Dandelion Root

Dandelion is a medicinal and herbaceous plant with broad development prospects and high comprehensive utilization value.This project selected dandelion root as the experimental material,the extraction process of dandelion root polysaccharide,separation and purification methods,preliminary analysis of the structure and antioxidant activity in vitro were studied,according to its functionality developed dandelion functional beverages,aimed to provide useful support for the development and comprehensive utilization of dandelion.The main research contents and results are as follows:(1)Dandelion root polysaccharide extraction methods.The experiment was based on the yield of dandelion root polysaccharides.By comparing the hot water extraction method,ultrasonic assisted hot water extraction method and ultra high pressure method.It was found that the highest yield of polysaccharide extracted by the ultra-high pressure extraction method was 14.29%.The operation of the ultra-high pressure equipment at room temperature avoids the loss of polysaccharide due to high temperature,and significantly shortens the extraction time and increases the extraction efficiency.Response surface experiments were performed on the basis of single factor experiments.The optimal conditions for the extraction of dandelion root polysaccharides by ultra-high pressure method were as follows:pressure holding time 7 min,pressure 300 MPa,and solid-liquid ratio 1:25 g/mL.(2)The study was on the separation and purification methods of dandelion root polysaccharides.The crude polysaccharide was decolorized by activated carbon.The optimal conditions for decolorization were obtained by single factor and orthogonal experiments:the amount of activated carbon was 2%,the temperature was 40?,time was 30min,and pH was 4.0.The decolorization rate of polysaccharide was 88.3%,and the polysaccharide retention rate was 65.8%.Deproteinized and decolorized dandelion root polysaccharides were successively separated and purified by DEAE-52 cellulose and Sephadex G-100 Sephadex column to obtain three components DRP1-1,DRP2-2,and DRP3-3.The total polysaccharide purity was 76.5%.(3)The preliminary study was on the structural analysis and the antioxidant activity of dandelion root polysaccharide.According to infrared spectroscopy(IR)analysis,the three components obtained from the purification contained characteristic absorption peaks of five polysaccharides.The mass fractions of the three components in the dandelion root polysaccharide were determined by high performance liquid chromatography(HPLC):DRP 1-1 was 6.23×103,DRP 2-2 was 1.307×104,and DRP 3-3 was 9.48×103 Da.The monosaccharide composition and its percentages of the total polysaccharide were:D-rhamnose 8.7%,D-xylose 4.01%,D-arabinose 16.4%,glucose 27.6%,and D-galactose 17.1%.The results of the antioxidant activity of dandelion root polysaccharides showed that dandelion root polysaccharides can effectively scavenge hydroxyl radicals(·OH),superoxide radicals(O2-)and DPPH radicals,and had a positive correlation with polysaccharide concentration.(4)The study was on the development of dandelion root polysaccharide beverages:The dandelion stock solution was used as the base liquid,mixed with lemon juice,seasoned,and added with dandelion root polysaccharide,supplemented with honey,white sugar,CMC-Na,and formulated dandelion polysaccharide beverage.The best formula for dandelion root drink was:dandelion 8.0%of the stock solution,1.5%of lemon juice,3.04%of dandelion polysaccharide,2.0%of honey,5.0%of white sugar,0.01%of CMC-Na.The content of dandelion polysaccharide in the beverage prepared by this formula was 6.21%.Compared with the beverage without added polysaccharide,the antioxidant activity can be better exerted,and the product was light yellow,had the unique fragrance of lemon and dandelion,was suitable for the sweet and sour entrance,slightly bitter,liquid clarification,no precipitation,stability it was good.