Solar convective drying of Otala lactea meat: kinetic modeling, thermodynamic analysis, and multi-objective optimization of nutritional and functional quality

Otala lactea is a promising alternative protein source, yet the effects of solar convective drying on its quality remain poorly understood. This study evaluated the drying kinetics, composition, functional properties, and energy performance of O. lactea meat dried in an indirect forced-convection solar dryer at 40, 50, and 60°C and airflow rates of 150 and 300 m 3 /h, using freeze-dried samples as a reference. Each drying condition was performed once, while compositional and functional analyses were conducted in three technical replicates. Solar-dried treatments were assessed by two-way ANOVA for temperature, airflow, and interaction effects, and compared with the freeze-dried reference using Dunnett-adjusted tests. Among 12 thin-layer models, the Midilli-Kucuk model showed the best fit (R 2 = 0.9996). Arrhenius analysis gave an apparent activation energy of 41.22 kJ/mol (R 2 = 0.9976). Drying conditions significantly influenced proximate composition, mineral profile, and functional properties, with temperature being the main source of variation. PCA showed that PC1 and PC2 explained 69.8% of total variance. The highest protein content was obtained at 50°C-300 m 3 /h (66.39 ± 1.96% dry matter). Exploratory multi-criteria optimization ranked 60°C-150 m 3 /h highest (91/100; SEC 13.9 MWh/kg), representing the best overall quality–process compromise rather than the minimum-energy condition. These findings support selection of promising drying conditions for future validation and scale-up.