Characterization of Alkali Extracting Polysaccharides from Cultured Cordyceps militaris

Polysaccharides from many sources, catching more and more attention because of their multiple pharmacological activities [1-4], can be extracted by hot water, alkali, and enzyme and so on. In traditional viewpoint, polysaccharides are soluble in water for their hydroxyl and the solubility is the base of its bioactivities while insoluble polysaccharides have low or no bioactivities. The predominant extracting method is hot water extraction to date because of low productivity and restricted research technology of other method. However, the method has some defects, including high extraction temperature and long time to operate, which probably lead to degradation of polysaccharides. Moreover, a great deal of residue, possibly containing active components, is discarded after hot water extraction. Alkaline extraction is another commonly used method to extract polysaccharides and the products usually have bioactivity [5-8]. Nevertheless, most of the researchers focus on polysaccharides extracted by hot water. As a result, there are fewer researches about polysaccharides extracted by alkali as well as their corresponding biological activities, and those about water insoluble polysaccharides are even more less.