Ouagadougou: Faced with significant post-harvest onion losses, Dr. Boukare Ouedraogo, a lecturer and researcher at Norbert Zongo University, is proposing an innovative solar-based solution. In an interview with AIB, he presented the "solar cell for preserving agri-food products," highlighting accessible and scientifically validated techniques to improve onion preservation and increase producers' incomes.
According to Burkina Information Agency, Dr. Ouedraogo emphasized the importance of planning onion storage from the start of nursery establishment, distinguishing between onions meant for storage and those for immediate consumption. This involves selecting a suitable variety and adhering to production guidelines recommended by agronomists. Key post-harvest practices, such as cutting the bulbs correctly, transporting them carefully, and conducting the "curing" process to remove excess water, are essential for forming a protective layer that reduces losses and damage.
Heat transfer plays a crucial role in onion preservation. Improper heat management during the curing process can lead to rapid water loss and spoilage. Dr. Ouedraogo stresses the need for controlling heat, ensuring good ventilation to remove moisture, and using dry air. The critical parameters for effective storage include temperature, humidity, and ventilation, which are influenced by heat transfer. The Sahelian context adds the challenge of external heat from the sun, impacting storage conditions through radiation, convection, and conduction.
Scientific factors contributing to onion losses involve air exchange control, management of external heat shock, and humidity control. Poor handling of these factors, especially during the wet season, promotes rot. Optimal storage requires maintaining a temperature between 25 and 30°C, a relative humidity of 65 to 75%, and an air exchange rate of 250 to 300 m³/h per ton of onions.
Dr. Ouedraogo suggests that producers follow technical guidelines from agricultural engineers to ensure proper preservation. Storing onions in unsuitable conditions, such as poorly ventilated areas, can lead to significant losses. Technologies are available to improve preservation, but their success depends on the producers' discipline.
The solar-based technology developed by Dr. Ouedraogo is adaptable to various regions, including West Africa, and can be adjusted if necessary.