Kinetics of the combined drying technology of pear slice (Pyrus)
2009
Pavkov, I. | Babic, Lj. | Babic, M. | Radojcin, M., Faculty of Agriculture, Novi Sad (Serbia)
The aim of the research was measuring the influence of analysed factors of osmotic and convective drying on the change of moisture of the pear and increase of dry matter. The factors of osmotic drying were temperature and solution concentration, and factors of convective drying were temperature and air velocity in front of the layer of the material. During the osmotic drying, the most significant change concerning moisture and the increase of dry matter happened in the first 100 minutes of the process. A change in moisture is also detected later in the process, but the velocity of that change decreased. In 180 minutes the moisture decreased from the initial value of 0.82 kg/kg to 0.775 kg/kg for solution temperature of 60 deg C and solution concentration of 50 degree Bx and 0.776 kg/kg for solution temperature of 40 deg C and solution concentration of 50 degree Bx. Maximum recorded increase of dry matter equaled 0.036 kg/kg for the solution temperature of 60 deg C. Within the period of 24 hours of convective drying, the biggest decrease in moisture was achieved in air temperature of 60 deg C and air velocity of 1.5 m/s. The moisture of the material decreased from the initial value of 0.776 kg/kg to 0.453 kg/kg, and tissue temperature equaled 57.34 deg C. Evaluation of the chosen factor levels influences of convective drying on the speed of drying by dispersive analysis was conducted. The results of dispersive analysis pointed out the significant influence of chosen levels of air temperature and decreased influence of chosen levels of air velocity on the speed of drying.
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