Performance and quality assessment of microwave-pre-treated solar drying of potato slices using an Arc'Teryx dryer

Improving drying efficiency while preserving quality remains a major challenge in processing high-moisture potato (Solanum tuberosum L.) tubers. This study specifically investigated the influence of microwave pre-treatment followed by solar drying on drying efficiency and potato powder quality. This study investigated the combined effects of slice thickness (3–7 mm) and microwave pre-treatment (0–6 min) on the drying performance and quality of solar-dried potato powder. A two-factor factorial design evaluated drying kinetics, physicochemical and functional properties, and nutrient retention. Slice thickness and microwave pre-treatment significantly (p < 0.05) affected drying behavior. The shortest drying time (5.67 h), highest drying rate, and greatest moisture loss occurred with 3 mm slices and 6 min microwave pre-treatment, demonstrating enhanced heat and mass transfer. The improved drying performance is attributed to microwave-induced structural modification of potato tissues, which enhanced internal moisture migration during subsequent solar drying. The drying process occurred entirely within the falling-rate period, indicating diffusion-controlled moisture removal. Quality evaluation showed that optimized drying conditions improved color, lightness, and vitamin C retention (up to 10.40 mg/100 g), while proximate composition and mineral content remained largely unchanged. Functional properties also improved, with increased water absorption capacity (up to 271.53%) and oil absorption capacity, and reduced bulk density, indicating better rehydration and handling. Interaction effects further confirmed that microwave pre-treatment enhanced internal moisture migration through structural modification. Overall, microwave pre-treatment followed by solar drying effectively produced high-quality potato powder with improved drying efficiency and desirable quality attributes, reducing post-harvest losses.