Drying Temperature and Storage Duration for the Retention of Bioactive Compounds of Selected Wild Edible Plants From Ethiopia

Foods rich in bioactive compounds significantly prevent chronic diseases; however, these compounds are susceptible to drying temperature and storage duration because they lose some of their functionalities. This study aimed to determine effective drying temperatures and storage durations for better retention of bioactive compounds of three Ethiopian wild edible plants: Mussaenda arcuata, Celosia trigyna, and Pteridium aquilinum. The collected samples were oven-dried at 60°C, 65°C, and 70°C in a convective oven dryer to equilibrium moisture content and cooled to room temperature and analyzed for ascorbic acid, β-carotene, total flavonoid and phenolic contents. To select an appropriate mathematical model for drying, parameters to determine the drying kinetics were also collected simultaneously. The results showed that the dried sample at 60°C exhibited better retention of ascorbic acid, β-carotene, and flavonoids, except for the phenolic content of Celosia trigyna at 65°C. Drying kinetics results in the Henderson and Pabis's model best fitted for Mussaenda arcuata and Celosia trigyna, while a two-term model is fitted for Pteridium aquilinum. After determining the optimum drying temperature, the samples were then packed with polyethylene bags and stored at room temperature for 12 months. The phytochemical contents were also analyzed at 0, 4, 8, and 12 months to determine the optimal storage time. Storage analysis over 12 months showed significant degradation of bioactive components, particularly ascorbic acid in Mussaenda arcuata (47.57% loss within 4 months), with a half-life time of 4.56 months. Therefore, drying at 60°C and consuming the products in 4 to 6 months ensures better retention of bioactive compounds, supporting the effective use of wild edible plants to promote improved nutrition, sustainable food processing, and improved food and health security in both rural and urban communities.