Comparison and Modeling of the Drying Kinetics of Moringa Leaves Using a Closed Facility in the Field and Using a Convective Tray Dryer

Abstract

[EN] Climate change requires a transition to crops that need less water and are more tolerant of high temperatures. In this regard, the adaptation of Moringa oleifera to the Spanish Mediterranean Basin offers the sustainable alternative production of a plant with a high nutritional value. It might also serve as a substitute crop with significant economic potential in less developed tropical regions in the world. Moreover, to provide the market with a homogeneous product, the stabilization of the leaves is necessary. The lack of control in the traditional form of moringa leaf drying (which only makes use of shade and air) does not guarantee a final homogeneous water content that can extend the crop¿s shelf life. Consequently, the purpose of this study was to develop a modular, affordable, and expandable dryer that enables the dehydration of leaves in the same field, lowering production costs in the process. The drying kinetics of leaves from crops of different ages (1 and 4 years) have been fitted to several mathematical models, using the ¿field dryer¿ and a semi-industrial tray dryer. In addition, their physicochemical properties were also compared. The outcomes demonstrate the viability of the field dryer¿s design. The drying kinetics of both dryers were more effectively adapted to the logarithmic model. Due to the variable air conditions in the field, the equilibrium moisture level attained was somewhat greater using the field dryer than using the tray dryer, but the product color and antioxidant and protein contents were similar. Finally, younger plants produced leaves with greater antioxidant capacities and a lower final water content.