PL
W artykule przedstawiono badania mające na celu wyjaśnienie wpływu ciśnienia stosowanego podczas obróbki wstępnej na przebieg procesu suszenia konwekcyjnego jabłek oraz zmiany współczynnika dyfuzji wody wynikające z zastosowania zmiennych warunków ciśnienia podczas obróbki osmotycznej. Zakres doświadczeń obejmował zastosowanie ciśnienia zredukowanego i podwyższonego względem atmosferycznego. Podjęto próbę wyznaczenia współczynnika dyfuzji wody w czasie suszenia konwekcyjnego jabłek
EN
Pressure influenced significantly heat and mass transfer condition during convective drying apples osmotically pre-de- hydrated. Curves of drying and velocity were determined by using high pressure of the grade 50 and 500 MPa. The rise above the atmospheric pressure during osmotic pre- treatment cause significant decreasing of the initial water content. At the same time through internal structure changes, using of pressure influence also decreasing of the final water content in the conditions of drying. The course of drying and velocity curve for apples pre-dehydrated in different pressure condition have in the whole studied range of the water con¬tent, decreasing character. High pressure treatment during osmotic dehydration cause, that those curves are characteri¬zed by exponential function. Pressure change during osmotic dehydration influence values of the both average (appointed for the whole course of dry¬ing curve) diffusion coefficient and also that one appointed in the lockers of reduced water content. The lowest values of average diffusion coefficient of water was noticed for apples pre-treated in over pressure condition. At the same time dif¬fusions coefficients appointed in the lockers of water content, are characterized by decreasing course, till the achievement of reduced -water content at the level of 0,2 (about 200 minutes of drying).