THE MOISTURE-CONTENT RELATIVE-HUMIDITY EQUILIBRIUM RELATIONSHIP OF WHEAT - A REVIEW

Thirty three sources of hygroscopic data for wheat are identified. Gra vimetric methods predominate in the literature, followed by hygrometri c methods which largely employ a dew point technique for relative humi dity determination. Hysteresis effects vary considerably in magnitude. The greatest difference between adsorption and desorption isotherms o ccurs in the 20 - 40% RH region. A table of equilibrium moisture conte nts interpolated from the data sets is presented for a fixed set of te mperatures and RH to enable comparison. The isotherm equations used to fit the data are also reviewed. The Strohman-Yoerger, Modified-Oswin, Modified-Chung-Pfost, Chen-Clayton and Modified-Henderson equations a re identified as the most suitable. Further investigation is needed to compare them.