earticle

영어

Adsorption isotherms for chaga mushroom powder as influenced by particle size were investigated using a gravimetric technique. Samples were equilibrated in desiccators containing sulfuric acid solutions of known water activity (0.11-0.93), then placed in temperature-controlled chambers for approximately ten days. Equilibrium moisture content (EMC) of chaga mushroom powder increased with water activity in all samples. EMC was slightly greater in the samples comprised of smaller particle size, however there was no marked difference in appearance between the three samples. The chaga mushroom powder exhibited Type II behavior. When the BET model was used to determine mean monolayer values, 0.077, 0.077, and 0.070 H2O/dry solid was observed for <250, 250-425, and 425-850 um sized samples, respectively, however mean monolayer values were 0.121, 0.111, and 0.101 H2O/dry solid, respectively, when the GAB model was used. The experimental EMC values were related to the computed values from Henderson's model. The coefficient of determination and standard error for the linear regression were 0.997 and 0.003, respectively.