EQUILIBRIUM MOISTURE CHARACTERISTICS OF SUNFLOWER SEEDS, HULLS, AND KERNELS

The equilibrium moisture content (EMC) of sunflower seeds, hulls, and kernels at 10, 25, 40, and 55-degrees-C were determined by equilibrating the samples to known relative humidities above saturated salt solutions. EMC of the hulls was higher and EMC of kernels was lower than that of seeds at all temperatures and equilibrium relative humidities (ERH). Equilibrium moisture curves of seeds of three hybrids with oil contents ranging from 34.9 to 47.5% (dry basis) at 25-degrees-C were practically coincidental when the moisture contents were calculated on an oil-free basis. At 55-degrees-C, equilibrium moisture contents of three hybrids were not affected by oil content. Fitting of data to four sorption models (Henderson, Chung-Pfost, Halsey, and Guggenheim-Anderson-de Boer) revealed that the GAB equation gave the best fit to the experimental data for individual temperatures. But for the consideration of temperature dependence, the Halsey equation was an acceptable model for describing EMC-ERH data of sunflower seeds, hulls and kernels.