Study on the Optimum Extraction Process of Mulberry Leaf Polysaccharide

The experiment was conducted to study the best extract process of mulberry leaf polysaccharide,three factors and three levels orthogonal test was designed to optimize the extraction process.Three factors were considered,including ratio of solid to liquid,decoction time,the time of extracting and the yield of mulberry leaf polysaccharide was determined with phenol-sulfurie acid colorimetry as the evaluate index.Meanwhile,the influence of ethanol concentrations on mulberry leaf polysaccharide extract was studied.The results showed that decoction times could greatest affect the extraction percent of the polysaccharides.The extraction percent of polysaccharide was the highest (4.94%) when the rate of solid to liquid was 25,the time of extracting was 2 h and decoction times was 2.While the most appropriate process was 25 times for the rate of sdid to liquid,2 h for extracting and decoction times was 3,considering with practical situations.The concentration of ethanol would significantly affect polysaccharides yield and purity.When the concentration of ethanol was 70%,the yield of mulberry leaf polysaccharid was highest.When the concentration of ethanol was 40%,the content of mulberry leaf polysaccharide was highest (41.5%),significantly higher than other ethanol concentration (P < 0.05).It suggested that the higher the ethanol concentration,the lower the polysaccharide content,but the higher the yield.The optimum extraction of mulberry leaf polysaccharides were that the rate of solid to liquid was 25,extractign for 2 h,decoction 3 times and 70% ethanol precipitation.