MOISTURE SORPTION CHARACTERISTICS OF FREEZE-DRIED, OSMOFREEZE-DRIED, AND OSMO-AIR-DRIED CHERRIES AND BLUEBERRIES
Equilibrium moisture contents (EMC) of freeze-dried, osmo-freeze-dried, and osmo-air-dried sweet cherries 
(‘Bing’) and highbush blueberries (‘Bluecrops’) at 10, 25, and 40°C were determined by equilibrating samples to eight 
different humidities. Moisture sorption isotherms of cherries and blueberries displayed characteristics typical of highsugar 
foods with crossing points at 0.4 to 0.8 water activity (aw) depending on temperature. Fitting of five sorption 
models (modified Henderson, Chung-Pfost, Halsey, Oswin, and Guggenheim-Anderson-de Boer) to data showed that the 
modified Henderson equation predicted isotherms with the smallest standard error of moisture content and mean relative 
percent error values. None of the equations described the EMC data adequately for the entire range of ERH. The modified 
Henderson equation was found to give a good fit at aw < 0.8. For aw < 0.5, the modified Oswin and Halsey equations 
gave acceptable results. However, the Halsey equation was the best model for aw > 0.8.