Investigation of Radiofrequency Drying Kinetics of Turmeric Slices and Its Mathematical Modeling

ABSTRACT

The drying kinetics of turmeric slices was investigated using a radiofrequency dryer. The drying experiments were conducted at three slice thicknesses (2, 4, and 6 mm) with exposure duration per run of 5, 10, 15, 20, and 26 min and drying temperatures of 40°C, 50°C, and 60°C achieved by varying the conveyor speed and the electrode gap, respectively. The shortest drying time of 55 min was observed at the exposure duration per run of 5 min. The slice thickness, temperature, and the exposure duration showed significant effects over the drying kinetics of the turmeric slices. The mathematical modeling results showed that among the evaluated thin layer drying models, the radiofrequency drying process showed a good fit for nine models. Page model exhibited best‐fit for the obtained experimental drying kinetics with the highest R ² value of 0.9998 and the least error values. The effective moisture diffusivity within the turmeric slice during radiofrequency drying was valued between 0.156 × 10 ⁻⁰⁹ and 0.243 × 10 ⁻⁰⁹ for the varying exposure time per run. These research findings support the applicability of radiofrequency drying for efficient dehydration of turmeric slices.