MATHEMATICAL MODELING OF CONCENTRATIONS OF GRAPE, POMEGRANATE AND BLACK CARROT JUICES BY VARIOUS METHODS

摘要

In the present study, grape, pomegranate and black carrot juices were concentrated to 65 °Brix (Bx) from initial concentrations of 15.93, 13.91 and 11.23 °Bx respectively. The concentration kinetics of the juices were investigated using a rotary vacuum evaporator at 80°C, a microwave vacuum evaporator at 180 W and 300 W and osmotic distillation (OD) at room temperature. Experimental data were compared according to three statistical parameters: the correlation coefficient (R 2 ), reduced chi-squared (χ2) value, and root mean-square error (RMSE), with values predicted by 13 models. Midilli model exhibited a better fit for the concentration kinetics (R 2 ≥ 0.9990; χ 2 ≤ 0.4588; RMSE ≤ 0.5350) than the other models, in general. This model was followed by the logarithmic, Page and two-term exponential models. The logarithmic model exhibited slightly better fitting for the thermal concentration method than Midilli model. The lowest energy consumption (1.334-1.540 kWh) was determined for the OD technique.