Moisture sorption characteristics of food powders containing freeze dried avocado, maltodextrin and inulin

Moisture adsorption isotherms of the freeze-dried powders containing avocado, maltodextrin and inulin with different ratio, were determined using gravimetric static method of saturated salt solutions at 25 °C and the range of the water activity from 0.11 to 0.86. The data obtained were evaluated using sorption models: BET (Brunauer-Emmett-Teller), GAB (Guggenheim, Anderson and deBoer), Peleg, Lewicki, Oswin and Henderson. The goodness of the fit evaluated on the basis of criteria such as coefficient of the determination and root mean square values. Sorption isotherm of the pure avocado powder was III type while curves plotted for others powders showed sigmoid shape. It was found that the Peleg model was the most adequate for representation of the sorption data of all analyzed blends. In order to characterize the research material, chemical composition of the edible part of the avocado fruit was determined. Main component of the dry matter was fat.