Thermal studies on Tremella fuciformis polysaccharide-water interaction

Characteristic features of polysaccharide derived from fungi (Tremella fuciformis), which are believed to have medical attributes for longevity, were investigated from the viewpoint of water interaction properties. Phase transition behaviour of Tremella fuciformis polysaccharide (TFP) in the presence of water in a range from 0 to 2.5 (mass of water / mass of dry sample, g g-1) was measured by differential scanning calorimetry in a temperature range from 123 to 281K. Four transitions, i.e., glass transition, cold crystallization, melting and endotherm at a temperature higher than melting were detected. Furthermore, bound water content of the TFP was evaluated from the enthalpy of melting. From these results were obtained that non-freezing water content of TFP is similar to that of hyaluronan and larger than those of ordinal water-soluble polysaccharides. It is suggested that the chemical structure of TFP with dense placement of the hydroxyl groups is attributed to the above characteristic water binding.