Electrohydrodynamic Drying of Carrot Slices

Abstract

Carrots have one of the highest levels of carotene, and they are rich in vitamins, fiber and minerals. However, since fresh carrots wilt rapidly after harvest under inappropriate storage conditions, drying has been used to improve their shelf life and retain nutritional quality. Therefore, to further investigate the potential of this method, carrot slices were dried in an EHD system in order to study the effect of different voltages on drying rate. As measures of quality, carotene content and rehydration ratio were, respectively, compared against the conventional oven drying regime. Carotene, the main component of the dried carrot, and rehydration characteristics of the dried product can both indicate quality by physical and chemical changes during the drying process. Mathematical modeling and simulation of drying curves were also performed, using root mean square error, reduced mean square of the deviation and modeling efficiency as the primary criteria to select the equation that best accounts for the variation in the drying curves of the dried samples. Theoretically, the Page model was best suited for describing the drying rate curve of carrot slices at 10kV to 30kV. Experimentally, the drying rate of carrots was notably greater in the EHD system when compared to control, and quality, as determined by carotene content and rehydration ratio, was also improved when compared to oven drying. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the drying properties of carrots, and, as a result, it provides deeper insight into the industrial potential of the EHD drying technique.