Mathematical modeling on hot air drying of thin layer apple pomace

The hot air convective drying characteristics of thin layer apple pomace were evaluated in a laboratory scale dryer. The drying experiments were carried out at 75, 85, 95 and 105 degrees C and at the air velocity of 1.20 +/- 0.03 m/s. Different mathematical models were tested with the drying behavior of apple pomace in the dryer. The results indicated that the Logarithmic model can present better predictions for the moisture transfer than others; the drying process took place in two falling rate periods, the effective diffusivities in the second period were about six times greater than that in the first period; the general relationship of moisture ratio against drying duration in the thin-layer convective drying of apple pomace were found and can be used in design and operation of the convective drying, suggested by 0.9923 of square correlation coefficient and 0.00001 of chi square. (c) 2006 Elsevier Ltd. All rights reserved.