Study On Extraction, Purification And Antioxidative Activity Of Polysaccharide From Litchi Flesh

Litchi is a plant of Litchi department of Sapindaceae, and originated from China. It is not only a kind food with good color, smell and tastes, but also a precious tonic. It has two functions as food and precious tonic. In recent years, some active ingredients extracted from litchi already have aroused people's interest. The research showed a lot of functional ingredients such as anthocyanin, phenolic acid, polysaccharide, proanthocyanidin. The substance extracted from litchi pit or peel have several physiological functions such as antioxidation, anti-inflammatory, anti-mutagenesis, preventing saccharine diabetes, hypdipidemic, but at present the research about the active ingredients including litchi polysaccharide extracted from litchi flesh is reported rarely. This paper studied on extraction, purification and antioxidative activity of polysaccharide from litchi flesh, which gave a foundation for the further research. The main results and innovations were as follows:1. The quantifying of litchi polysaccharide was used by the phenol-sulfuric acid, and determined the polysaccharide's content and scale factor from litchi flesh of several kinds of common litchi varieties including black leaf were compared. The result showed different litchi varieties had different content and scale factor of polysaccharide,and black leaf litchi was optimum to extract polysaccharide.2. Litchi polysaccharide was obtained by Microwave extraction. RSA experiment was carried out to determine the optimal condition of the extraction. The optimal condition were: Microwave time 10min, power 640W, and the water-to-flesh ratio 8.Under this condition, the yield of Litchi polysaccharide was 6.17%,the polysaccharides content was 60.1%. The yield and content of polysaccharide by using microwave extraction were higher than using hot water. The method of microwave was optimum to extract polysaccharide.3. The removal of protein in rude litchi polysaccharides was studied by three methods including Sevag method, TCA combined with Sevag method and enzyme combined with Sevag method. The research showed the enzyme combined with Sevag method was optimum. The removal rate of protein was 83.94%, the loss rate of polysaccharides was 24.56% by using 1% enzyme combined with 3 times Sevag method.4. The deproteinized polysaccharide was decolored with macroporous resin. The best...