Modelling of Thin-Layer Drying of Osmo-Pretreated Red Bell Pepper

The paper observes a thin-layer drying behaviour of red bell pepper. The red bell pepper (192 samples) was pretreated in osmotic solution of salt of concentrations 5–20% (w/w) at osmotic solution temperatures (30–60 °C) and osmotic process durations (30–120 min) and dried at 60 °C in a locally fabricated convective dryer after preformation of osmotic dehydration pretreatment process. Experimental moisture content values obtained from the drying process were converted to moisture ratios. Seven existing thin-layer drying model equations were used for model equation fitting. The predicted and experimental (observed) moisture ratios were analysed statistically. The statistical indices and rules used to judge and select the model equation that would best describe the process were the highest values of coefficient of determination (R²); the lowest values of chi-square (χ²), root mean square error (RMSE), and sum of squares error (SSE). Results showed that the two-term exponential model equation best described the drying behaviour of osmo-pretreated red bell pepper. The ranges of statistical indices of selected two-term exponential model equation are: R² (0.9389–0.9751), χ² (0.0642–0.1503), RMSE (0.2032–0.1668), and SSE (0.6424–1.5027).