Comparative Study on Extraction of Crude Polysaccharides from Dendrobium Candidum and Removing Protein Procedure

Objective: To study the best extraction condition of crude polysaccharides from Dendrobium Candidum and methods for deproteinization. Method: By combining single- factor and orthogonal experiments to explore the best extraction technology of crude polysaccharides from Dendrobium Candidum,we compared the deproteinization methods of hydrochloric acid and trichloroacetic acid. Results: The results showed that the best extraction condition for crude polysaccharides was as follows. The extraction temperature was 70 ℃. The ratio of solid to liquid was 1 ∶ 40 and the time was 4 h with once extraction. Of the four conditions,temperature had the greatest influence on crude polysaccharides extraction.The best method of protein removal rate was hydrochloric acid method at p H = 3. Conclusion: The optimized extraction process was stable while the yield of crude polysaccharides can reach 4. 67%. When p H = 3,via hydrochloric acid method,the content of polysaccharides can be the highest,which is more suitable for actual production.