Extraction and preliminary characterization of polysaccharide from Umbilicaria esculenta cultivated in Huangshan Mountain

In this study, the effects of extraction temperature, extraction time and liquid–solid ratio on the extraction yield of polysaccharide (HSSEP) from Umbilicaria esculenta cultivated in Huangshan Mountain were investigated using Box–Behnken response surface design. A second-order polynomial equation was employed to optimize the heat water extraction of HSSEP. The optimal extraction conditions of HSSEP were: 100.37 °C extraction temperature, 0.98 h extraction time and 11.02 mL/g liquid–solid ratio. Under these conditions, the maximum extraction yield of HSSEP was 27.68%. Additionally, two purified polysaccharide fractions, designated as HSSEP1 and HSSEP2, were prepared from HSSEP. The results indicated that HSSEP1 and HSSEP2 were acidic polysaccharides. HSSEP1 was mainly composed of mannose, glucose and galactose, in a ratio of 12%, 76% and 12%, respectively, while HSSEP2 was mainly composed of glucose. This study demonstrated the optimal extraction conditions and structure characterizations of HSSEP for the...