Impact of different drying methods on antioxidant properties of Moringa oleifera leaves

Abstract:

Moringa oleifera leaves are among the most nutrient-dense greens consumed in the tropics, yet their short shelf life limits year-round availability. Drying extends storability but may degrade heat-sensitive bioactives. This research compared three drying methods—shade drying (ambient), tray drying (40-80 °C), and open sun drying—for their impact on total phenolic content (TPC), DPPH radical scavenging, vitamin C, β-carotene, and colour of Moringa leaf powder. Work was carried out at the Department of Food Processing, University for Development Studies, Tamale, Northern Region, during September-December 2023. Shade drying retained the highest antioxidant activity (DPPH 81.2%, TPC 84.3 mg GAE g⁻¹) and vitamin C (128.4 mg/100 g), followed by tray drying at 50 °C (DPPH 72.1%, vitamin C 98.3 mg/100 g). Sun drying caused the greatest losses across all parameters. Tray drying at 50 °C offers a practical compromise between antioxidant retention and drying speed for small-scale processors.