Thin‐layer drying kinetics and mathematical modelling of osmotically pretreated vacuum dried green chilli

Abstract Background Chilli is highly perishable, often requiring drying to extend shelf life. This study assesses and compares the drying kinetics of osmotically pretreated green chilli under vacuum drying conditions while evaluating suitable mathematical models and calculating effective moisture diffusivity and activation energy. Results Sliced chilli samples were osmotically dehydrated (optimised: 40°C, 30 °Brix, 99.32 min) to 68.87% ± 0.6% moisture, then dried in a vacuum oven (50 kPa) at 50, 60, and 70°C. The drying process primarily occurred during the falling‐rate period, with significantly reduced temperatures resulting in shorter drying times (13 h at 50°C vs. 9 h at 70°C). The Page model provided the best fit for the drying curves, and the effective moisture diffusivity ranged from 3.92 × 10 −10 to 5.16 × 10 −10 m 2 /s. Activation energy was determined to be 12.57 kJ/mol. Conclusion Vacuum drying with osmotic pretreatment efficiently dehydrates green chilies and lowers the activation energy, thereby enhancing moisture removal. The Page model, diffusivity values, and insights into activation energy contribute to optimising drying processes. This method can significantly shorten drying times and preserve product quality, offering a promising industrial approach for chilli drying that may help minimise post‐harvest losses.