Comparative Drying Kinetics, Moisture Diffusivity Modeling and Processing Method Detoxification Efficiency of Cassava Root Chips

Abstract

This study comparatively evaluates the drying kinetics, moisture diffusivity, and processing method detoxification efficiency of cassava root chips under oven and sun drying conditions. Thin‐layer drying experiments were conducted using chips of 10 × 5 × 0.2 mm, with oven drying at 30°C–100°C for 70 min and sun drying at daytime ambient temperatures over an effective exposure time of 2520 min. Moisture ratio data exhibited a short constant‐rate period followed by a dominant falling‐rate phase, confirming diffusion‐controlled drying. The Logarithmic model best described the drying behavior with R 2  = 0.94–0.98, RMSE < 0.02, and drying‐rate constants of 2.87 × 10 −4  min −1 to 3.42 × 10 −4  min −1 and 0.0120 min −1 to 0.0160 min −1 for sun and oven drying methods respectively. Effective moisture diffusivity ranged from 8.11 × 10 −13 to 1.08 × 10 −12  m 2 /s for oven drying and 5.62 × 10 −14 to 6.49 × 10 −14  m 2 /s for sun drying, with oven drying enhancing mass transfer by up to three orders of magnitude. Cyanide detoxification followed a coupled reaction–mass transfer mechanism, transitioning from enzyme‐driven hydrolysis to diffusion‐controlled volatilization of HCN. Sun drying achieved 83%–89% cyanide reduction over 2520 min, with detoxification rate constants of 7.69 × 10 −4  min −1 , 13 times lower than oven detox rate constants of 2.0 × 10 −2  min −1 . The results demonstrate that moisture diffusivity is the key controlling parameter linking drying kinetics and detoxification efficiency, highlighting the need for integrated process optimization to achieve safe and energy‐efficient cassava processing.