A multidimensional study on tomato drying in greenhouse solar systems: From life cycle impacts on quality characteristics

This study focuses on the performing a life-cycle assessment of two different solar drying systems developed in Gwalior, Madhya Pradesh, India. Present study evaluates the thermal characteristic and morphology analysis of tomato slices in a greenhouse solar drying system (GHSDS) and compares it with traditional open sun drying (OSD) methods. Experiments assessed drying characteristics, mass transfer coefficient, and quality of dried tomato slices under both drying techniques. The GHSDS achieved a maximum temperature of 59.5 °C with solar intensity of 855 W/m². The initial moisture content of 81.25 % in tomato slices decreased to 11.22 % in GHSDS and 22 % in OSD within 10 h. Drying rates were 0.65 for GHSDS and 0.61 kg water/kg solid. hr for OSD. The Prakash and Kumar model accurately described the drying kinetics for both methods. GHSDS showed increases of 6.45 % in effective moisture diffusivity, 7.07 % in mass transfer coefficient, and 46.6 % in heat transfer coefficient compared to OSD. Activation energy ($E_a$) was 35.32 kJ/mol for GHSDS and 61.54 kJ/mol for OSD. The Life Cycle Assessment (LCA) technique was employed to compare the environmental impacts of a GHSDS with those of a parabolic solar drying system (PSDS). The results revealed significant differences between the two systems across all evaluated categories. The GHSDS consistently demonstrated a lower environmental impact compared to the PSDS. This study is the first to integrate drying kinetics, thermal performance, quality assessment, morphology analysis, and a full Life Cycle Assessment of greenhouse solar drying for tomato slices.