Optimum Extracting Technology of Intracellular Polysaccharides from Cordyceps militaris

The suitable extraction condition of intracellular polysaccharides from submerged-cultured Cordyceps militaris was investigated in the study. The optimum condition of hot water extraction has been investigated using orthogonal array design L9 (34) and extraction temperature, solid-to-olvent ratio, extraction time and number of extraction cycles were chosen as the independent variables. The optimization of extraction parameters were applied to further analyze the effects of hot water extraction, thermal cycling extraction, hydrochloric acid extraction, and sodium hydroxide alkali extraction on extraction rate of intracellular polysaccharides from Cordyceps militaris. The results showed that the optimum extraction conditions of hot water extraction for intracellular polysaccharides were established as follows: solid-to-solvent ratio of 1 : 40 (g/mL), 75 ℃, 2 extraction cycles, and 2.5 h each cycle. The sequence of factors that worked on the extraction rate of polysaccharides, in turn, is solid-to-solvent ratio, extracting temperature, extracting time and extracting times. The optimum extracting conditions of thermal cycling extraction method consisted of hot water extraction for 2.5 h in optimum condition followed by cold water extraction for 48h. The corresponding extraction rate of intracellular polysaccharides from these two extraction conditions were 14.74% and 15.92%, respectively. Sodium hydroxide extraction (55 g/L) and hydrochloric acid extraction (25 g/L) exhibited the highest extraction rate of 6.31% and 9.93%, respectively. In conclusion, the optimum?extraction method, in turn, is thermal cycling extraction, hot water extraction, hydrochloric acid extraction and sodium hydroxide extraction.