Separation Of Yam Polysaccharide And Development Of Compound Yam Beverage

Chinese yam, an traditional medicinal and edible food, has thousands of years planting history. It has been planted throughout our country. Yam polysaccharide, having a wide range of biological activity, is one of the major functional components of Chinese yam. The purpose of this paper is to set up a method to extract and purify yam polysaccharide, to determine its physical and chemical properties, to study its structure preliminary, to research its oxidation resistance, and to develop a compound beverage of Chinese yam, aiming at make full use of the value of yam.Water extraction of crude yam polysaccharide was optimized by means of orthogonal experiment. The results implied that the optimal conditions of water extraction were 60 degrees Celsius,3 hours,1 to 20 solid-liquid ratio and 3 times extraction. At the optimal conditions, the extraction rate of polysaccharide was 3.63%. Methods to remove protein on crude yam polysaccharide were contrasted, including Sevag method, trichloroacetic acid method and neutral protease method. Sevag method was better than trichloroacetic acid method and neutral protease method on protein removal.The related properties were determined and the polymerization forms were observed on purified yam polysaccharide (YP). The intrinsic viscosity of YP was 47.01mL/g. It had a strong oil absorption capacity, certain hygroscopic and moisture retention. Based on these properties, YP could be used in food industry. The macroscopic morphology of YP was loose porous fragment observed at scanning electron microscopy. The characteristic absorption peaks of furanose were detected by infrared spectroscopy. The particle size distribution was concentrated from 41.85nm to 374.12nm and 648.91nm to 1934.23nm.After the purification by Sephadex G-100 column chromatography, YP was eluted two constituent YP1 and YP2. It could be determined that both YP1 and YP2 was single pure substance after intensive elution, UV spectrum scanning and laser light scattering analysis.Antioxidant activities were determined on crude yam polysaccharide, YP, YP1 and YP2. The results implied that the order of antioxidant strength was YP>YP2> crude yam polysaccharide, while YP1 almost didn’t have any antioxidant, inferring that antioxidant activities of yam polysaccharides may be derived from the large molecular weight YP2, and the antioxidant activities would be good while the concentration of YP range from 3-5 mg/mL.A Compound Fruit Beverage with Chinese Yam and Wolfberry was developed. The beverage would be in a good condition of color protection when 0.3% sodium erythorbate, 0.3% sodium sulfite and 0.4% ascorbic acid. The time of color protection is 1.5h and the temperature of color protection is 40℃. The optimal formulation for this beverage is 35% of Chinese yam juice,20% of wolfberry juice,6% of sugar and 0.3% of citric acid. The optimal stabilizer formula is 0.10% of CMC and 0.20% of xanthan gum. The polysaccharide proportion was 0.382g/100mL, expecting the beverage could play a certain antioxidant effects.