Effect of Drying Temperature and Slice Thickness on Drying Kinetics, Moisture Diffusivity, Energy Use, and Color Change in Convectively Dried Chayote Squash Slices

Abstract

Insufficient fiber intake is strongly associated with chronic diseases. Chayote squash (Sechium edule), widely available in Indonesia, has potential as a fiber source, and drying provides a practical method for its use in food products. This study evaluated the drying kinetics, specific energy consumption (SEC), total color change (ΔE*_ab), and effective moisture diffusivity (D_eff) of chayote slices under different temperatures (50, 60, and 70 °C) and thicknesses (3 and 6 mm) to determine the optimum drying conditions. Drying time (DT) ranged from 150 min (70 °C, 3 mm) to 350 min (50 °C, 6 mm). The approximation of diffusion and the Midilli and others models best represented the drying kinetics. The highest SEC was 3.40×10⁶ kJ·kg⁻¹ (60 °C, 3 mm), while other treatments showed no significant differences. D_eff increased with temperature and thickness (3.38×10⁻¹⁰ to 1.28×10⁻⁹ m²·s⁻¹). Food color, an important factor influencing consumer acceptance, showed no significant ΔE*_ab differences across treatments. The optimum drying condition determined was 70 °C with 3 mm slices (DT of 149 min, ΔE*_ab of 16.62, SEC of 3.02×10⁶ kJ·kg⁻¹). These findings provide insights into designing chayote drying processes that achieve desirable quality while minimizing energy consumption.