The Extraction Process Of Chinese Yam Polysaccharide Complex And Its Quality Evaluation

Yam is generally welcomed in China and abroad as a kind of health foods, and yam polysaccharide is the main component of yam health products. To enrich the variety of water-soluble components in yam, one-step extraction with the alkaline process was used. By means of measuring the content of multiple water-soluble ingredients which in extraction to evaluate extraction efficiency. Using the polysaccharide extraction rate as an index, the influence of the solid-liquid ratio(g/mL)、pH、digestion timing、digestion temperature、extract times and particle size on extraction rate were investigated. The orthogonal experiment was used to determin the optimum process conditions of alkaline process in extracting yam polysaccharide. And a clarified process was used to remove some harmful heavy metal, tannins, so as to get a better extraction which is required. Finally, to inspect the related quality of the extraction,so as to adapt to the development and market demand better, and search the better quality。Through the orthogonal experiment, the optimum process conditions of alkaline process extract yam polysaccharide is determined:solid-liquid ratio1:10、extraction temperature50℃、pH10、extraction1.5h. The experimental results showed that under the best extraction conditions, the rate of yam compound polysaccharide extraction was5.716%, and the extraction contained polysaccharide, glycoprotein, crude fat, allantoin, saponins content were42.7582%,0.4497%,3.6869%,1.35%,0.66%. There were17kinds of amino acid in the extraction through the amino acid analyzer, which explain that the extraction contains a various amino acids.and the8essential amino acids to human body were complete. One of the highest content is glutamic acid3166.24mg/100g. Followed by arginine, Aspartic Acid, and serine content were1883.92mg/100g,1633.55mg/100g and1104.07mg/100g respectively. These showed that yam polysaccharide complex contained riched amino acids, high nutritive value and could be used for industrial production and health products. The optimum conditions of clarification process was,that add ZTC-Ⅱ natural clarify agent B first, then60℃heat20min.Finally add the ZTC-1I natural clarify agent A, heat preservation60℃under20min.The dosage of clarify agent B and A were1.2g/L and0.6g/L respectively, impurity rate was26.63%. The contents of lead、arsenic、mercury and copper in unclarified extraction are higher,and copper content was52.2674ug/g, arsenic was1353.651ng/g. The heavy metals was reduced to the half in the clarified extract,which indicates the clarify effect was good. We Measured the polysaccharide complex, refine from yam flour by alkaline process, on the amount of colony lump-sum of bacterium and coliform;and analysed the safety of polysaccharide complex by white rat test preliminary. The results showed that:the yam polysaccharides complex which extracted from yam powder to irrigate in mice stomach when the dose reached to5g\kg the mice without any adverse reactions, the totally number of coliform and bacterial colonies corresponding to the green food in the NY/T1511-2007were not exceed.