EQUILIBRIUM MOISTURE-CONTENT OF DRIED BLOOD FLOUR IN THE TEMPERATURE-RANGE OF 20-50-DEGREES-C

The paper presents results of water sorption tests of died blood flour carried out under laboratory conditions and mathematical analyses of sorption isotherms obtained Moisture equilibrium data were investigate d at air temperatures in the range of 20 - 50 degrees C and water acti vity ranging from 0.4 to 0.99. The experimental procedure used was a g ravimetric dynamic method with continuous registration of sample weigh t changes. Sorption capacity decreases as temperature increases. Rehyd ration of the dried material results in hysteresis bur this phenomenon was small. Four models of equilibrium moisture content/equilibrium re lative air humidity (Chung-Pfost. Halsey. Henderson and Oswin) were ev aluated for their ability to fit data for the samples of dried blood T he modified Henderson equation nas a good model for moisture adsorptio n and desorption of died blood flour.