engleski

Application of Peleg's model to Study of Drying Temperature Influencecon Dehydration and Rehydration of Potatoes

Peleg’ s two-parameter model was used to study drying temperature influence on dehydration and rehydration of potatoes. Conventional and ecological cultivated potatoes were fluid bed dried at 60, 70, 80, 90 °C and halogen dried at 60, 70, 80, 90, 100 °C. After dehydration soaking in water at room temperature were used for rehydration of dried potatoes. The experimental data were fitted with Peleg’ s model, which gave a good prediction of dehydration and rehydration kinetics in all experiments (R>0, 992). The Peleg rate constant (K_1) for dehydration process decreases with increasing drying temperature. This relations was linear for fluid bed drying and exponential for halogen drying that imply the bigger influence of drying temperature on dehydration kinetic during the halogen drying. The lesser K1 values for fluid bed drying suggested the greater initial drying rates in comparison with halogen drying at all drying temperature. Peleg’ s K_1 constants for rehydration process of dried potatoes were not much affected by drying temperature. It means that the initial rate of water absorption was similar for both potato cultivars regardless of drying temperature and drying method. The Peleg capacity constant (K_2) shows the mean influence of drying temperature on rehydration capability. An Arrhenius plot for K_2 exhibited slop change around 70 °C, which can correspond to gelatinisation temperature. Drying potatoes at higher temperatures (80 – 100 °C) caused an intensive structural changes and decreasing of rehydration capacity.

Peleg's model; dehydration; rehydration; potatoes

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