Thin-layer convective drying of plantain banana was performed at four different temperatures from 50 to 80 °C, with slice thicknesses from 2 to 8 mm. The drying curves, fitted to seven different semi-empirical mathematical models, were successfully used to fit experimental data (${\mathrm{R}}^2$ 0.72–0.99). The diffusion approach had better applicability in envisaging the moisture ratio at any time during the drying process, with the maximum correlation value (${\mathrm{R}}^2$ 0.99) and minimum value of $x^2$ (2$.5\times {10}^{-5}\mathrm{to}1.5\times {10}^{-4})$ and RMSE (5.0 $\times {10}^{-3}\mathrm{to}1.2\times {10}^{-2})$. The $D_{eff}$, $h_m$, and $E_a$ values were calculated on the basis of the experimental data, and overall ranged from $1.11\times {10}^{-10}$ to $1.79\times {10}^{-9}$ m² s⁻¹, $3.17\times {10}^{-8}$ to 2.20 $\times {10}^{-7}$ m s⁻¹ and 13.70 to 18.23 kJ mol⁻¹, respectively. The process energy consumption varied from 23.3 to 121.4 kWh kg⁻¹. The correlation study showed that the drying temperature had a close correlation with $h_m$ value and sample hardness. A significant (p < 0.05) increase in hardness of dried plantain banana was observed at 80 °C compared to the other temperatures. Additionally, the sample hardness and process energy consumption were more positively correlated with the thickness of the samples.

Green banana (Musa spp.) is a significant source of starch (resistant starch ∼50%), phenolics and flavonoid compounds, and minerals (K, Mg, Zn, and Fe). The utilization of green bananas in their fresh form is limited, whereas the drying of bananas provides the opportunity to use them for various purposes. Drying temperature and slice thickness are important to be optimized for drying of bananas as they affect the quality parameters. The present study was conducted using response surface methodology to optimize tray-drying temperatures (50–80°C) and slice thicknesses (2–8 mm) on the basis of phytochemical and physical parameters of dried green banana slices. The cubic model was found to be the best fit for most of the responses (R² = 0.95–1), and the quadratic model was fit for water activity () (R² = 0.92). The optimized drying conditions were found as drying temperature of 50°C and slice thickness of 4.5 mm. Experimental responses exhibited maximum L (84.06), C (13.73), and h^o(83.53) and minimum losses of total phenolic content (89.22 mg GAE/100 g) and total flavonoid content (3.10 mg QE/100 g) along with lower (0.25). The optimized green banana flour was rich in carbohydrates (77.25 ± 0.06%) and low in fat (1.79 ± 0.11%). The flour obtained had good flowability with a mean particle size of 60.75 ± 1.99 µm. Flour’s gelatinization and decomposition temperatures were 102.7 and 292°C, respectively. In addition, flour’s water absorption, oil absorption, and solubility were 5.19 ± 0.01, 1.58 ± 0.01, and 0.14 ± 0.02 g/g, respectively. Green bananas dried at optimized conditions resulted in a better product with less phytochemical loss than dried with other methods.