RT Journal Article ID 18d8b1431bd64b86 A1 Khondkar, Proma A1 Aidoo, Kofi E. A1 Tester, Richard F. T1 The Effects of Temperature, pH, and Cations on the Rheological Properties of the Extracellular Polysaccharides of Medicinal Species of Genus Tremella Pers. (Heterobasidiomycetes) JF International Journal of Medicinal Mushrooms JO IJM YR 2010 FD 2010-03-30 VO 12 IS 1 SP 73 OP 85 K1 Tremella K1 medicinal mushrooms K1 extracellular polysaccharides K1 medicinal value K1 rheological properties K1 Power law K1 ionic strength AB Extracellular polysaccharides were produced from nine Tremella species using the malt-yeast (MY) media. The rheological properties of the polysaccharide solution were examined by the Power-law model. The extracellular polysaccharide solutions showed shear-thinning (pseudoplastic) behavior. The pseudoplasticity was more pronounced for 5% polysaccharide solutions. T. cinnabarina and T. indecorata polysaccharide solutions (0.1% w/v) gave the highest and lowest viscosities—9.18 and 1.73 mPa, respectively—at 25°C and at a shear rate of 150 s−1. The effects of chemical and physical factors on solution viscosity were studied. The viscosity of solutions decreased with an increase in temperature and also at extreme pH values. Rheological analysis revealed that divalent cations (calcium and zinc) did not increase the viscosity of polysaccharides, but monovalent cations (sodium and potassium) did, which suggests that ionic bridging occurred between polymer chains. A synergistic increase in the viscosity of the solution was observed when the polysaccharides were mixed with xanthan. PB Begell House LK https://www.dl.begellhouse.com/journals/708ae68d64b17c52,7a925fcb5505d4dc,18d8b1431bd64b86.html