Effet de la fermentation sur la cinétique de séchage solaire des fèves de cacao

Résumé

Effect of fermentation on the solar drying kinetics of cocoa beans

Cocoa farming is a major agricultural activity for the economy of Côte d’Ivoire. Thus, the permanent improvement of the marketable quality of cocoa beans is essential for the sustainability of this agricultural capital. After harvest, fermentation and drying are the crucial operations on which the merchantability and organoleptic qualities of cocoa beans depend. To study the impact of these two post-harvest processes, experiments on the fermentation and drying of Forastero cocoa beans were carried out. Thus, 100 kg of fresh cocoa beans were fermented for varying times. The monitoring of the fermentation tests showed a decrease in the humidity of the cocoa beans from 61% to 52% in wet basis. The temperature of the cocoa beans increases gradually to reach a peak of 50°C after 5 days of fermentation. Which suggests an optimal fermentation time of 5 days. The pH varied between 3.5 and 5.5. Direct solar drying of fermented cocoa beans, and non-fermented control beans, was then carried out. The fermented cocoa beans, unlike the control beans, reached water contents less than or equal to 8%. Depending on the fermentation state, the drying kinetics of the cocoa beans showed a virtual absence of the constant rate phase. The evolution of parameters such as the rate of drying, speed and duration of drying have been analyzed.

Keywords: Cocoa beans; Fermentation; Drying kinetics; Temperature; pH.