Comparative assessment of drying kinetics and physicochemical properties of vegetables under different solar drying methods

This study compared drying kinetics, physicochemical quality, and sensory attributes of onion ( Allium cepa L.) and mint ( Mentha piperita L.) processed by solar tent drying (STD), sun drying (SD), and shade drying (ShD). According to the results, SD provided the fastest drying rate, followed by STD and ShD, whereas ShD preserved the highest total phenolic content (onion: 65.67 mg GAE/g; mint: 70.36 mg GAE/g), antioxidant activity (DPPH: onion 31.10%; mint 98.49%), and rehydration capacity (onion 272.2%; mint 60.87%). STD provided a balanced performance, preserving moderate bioactive content, acceptable color (ΔE = 12.15), and lower microbial loads (1.66 × 10 3 CFU/g) while shortening drying duration compared with ShD. In contrast, SD caused severe discoloration (ΔE = 30.34), greater shrinkage, and higher microbial counts. PCA confirmed distinct clustering of drying methods, with STD positioned between SD and ShD. Overall, STD represents a practical approach that improves efficiency while maintaining quality. • Solar tent drying balances quality retention with practical drying efficiency. • Tent drying preserves color and bioactives better than open sun drying. • Multivariate analysis confirms drying method as the main quality driver. • Shade drying maximizes quality but lacks operational feasibility.