Influences of Intermittent Drying on Local Fruits: The Case of Mangoes, Bananas, Potatoes, and Sweet Potatoes

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Résumé

In the context of promoting local agricultural products in the face of significant post-harvest losses in West Africa, optimizing drying methods is a key challenge. This research explores the impact of various intermittent drying regimes applied to four fresh products, namely mangoes (Mangifera indica), bananas (Musa sapientum), potatoes (Solanum tuberosum), and sweet potatoes (Ipomoea batatas) from the market in Ouagadougou (Burkina Faso). The objective is to evaluate the influence of intermittent drying kinetics on product quality. The samples, with an average unit mass between 150 and 350 g, were dried in an oven at 50°C, according to intermittent regimes varying from α = 1/2, 1/3, 1/4, 2/3, and 3/4 (drying time/rest time ratio). The reduced moisture content curves were obtained and the drying rate calculated. The drying time was shortened by 50%. The results indicate that for intermittent treatment, α = 1/2 for bananas, sweet potatoes, and potatoes, and α = 3/4 for mangoes, allows hygroscopic equilibrium to be achieved. The Langmuir and Peleg models were used to analyze the desorption isotherms. Peleg showed the best fit for bananas (R² = 0.98394; RMSE = 0.00272), while Langmuir proved more effective in describing mangoes (R² = 0.99708; RMSE = 0.00557), sweet potatoes (R² = 0.99825; RMSE = 0.00078), and potatoes (R² = 0.9989; RMSE = 0.00303) in a range of water activity from 20 to 88%. These results indicate that intermittent drying accelerates the drying of fruits and tubers while preserving their physical, structural, and nutritional qualities.

Mots-clés

intermittent drying, drying kinetics, mango, banana, potato, Ipomoea batatas, post-harvest losses, desorption isotherms, Peleg model, Langmuir isotherm, moisture content, hygroscopic equilibrium, food quality preservation