Engineered eggplant drying with sustainable green pretreatments for enhanced characteristics and physicochemical properties

The global issues of food insecurity and postharvest losses of perishable crops like eggplant (Solanum melongena L.) necessitate highly sustainable preservation methods. Traditional drying, while generally effective, can negatively impact product quality. Therefore, this research investigated green pretreatments including hot water blanching, ultraviolet irradiation, and ultrasonication to successfully enhance the characteristics and physicochemical properties of eggplant slices, using a customized tray dryer. These specific pretreatments were applied prior to drying at 35°C, 40°C, and 45°C, at a constant 2 m/s air velocity. Moisture diffusivity, porosity, surface area, and color were carefully analyzed. The Page model best fit the drying kinetics, determined via rigorous statistical analysis. Hot water blanching at 45°C yielded the highest moisture diffusivity (1.74x10-9 m2/s) and greatest porosity (0.775), indicating faster drying and more significant structural changes. While hot water blanching caused the most discoloration, ultrasonication retained color best. Hot water blanching also exhibited the lowest activation energy, clearly indicating the most efficient process. Ultimately, this study demonstrates that green pretreatments, particularly hot water blanching, significantly improve eggplant drying kinetics and modify physicochemical properties, contributing greatly to a more sustainable and efficient preservation process, thus offering a very promising potential solution for extending shelf-life and reducing food waste.