Impact of sun-drying and oven-drying on the biochemical and phytochemical properties of eggplant (Solanum aethiopicum)

In developing countries, vegetables such as the eggplant Solanum aethiopicum are grown locally. Its high water content makes this vegetable highly perishable; to address this problem, this study was conducted with the aim of reducing the water content in the eggplant as much as possible to extend its shelf life. Analysis of biochemical and phytochemical compounds was performed using standard methods. The results showed variations among most of the parameters analyzed. The water content in fresh eggplant is 90.2%, whereas dried eggplant samples have a water content of 9.1%. Regarding biochemical properties, sun-dried eggplants had higher levels than oven-dried eggplants and fresh eggplants. The ash, fat, protein, and fiber contents, as well as the energy value, ranged from (0.67 to 6.7%), (0.23 to 10.3%), (1.98% to 15.03%), (3.03 to 28.75%), (24.83 to 273.3%). As for minerals, with the exception of potassium and manganese, sun-dried eggplants had the highest levels compared to oven-dried and fresh eggplants. The levels range from Ca (6.11 to 57.14 mg/kg), Fe (3.75 to 35.88 mg/kg), K (3.45 to 37.89 mg/kg), Mg (7.42 to 89.78 mg/kg), Mn (3.39 to 33.60 mg/kg), Na (6.33 to 66.16 mg/kg), Zn (7.18 to 71.77 mg/kg). The levels of phytochemicals range from polyphenols (31.67 to 730.63 mg EAG/100 g), flavonoids (1.08 to 66.28 mg EAG/100 g), tannins (5.55 to 154.79 Emg/100 g), antioxidant activity (18.27 to 63.02 Emg/100 g). Drying is an effective method for adding value to African eggplants, as it both improves their shelf life and optimizes their nutritional quality.