Développement de solutions innovantes de séchage solaire adaptées aux fruits et légumes, en intégrant des méthodes de prétraitement et des séchoirs solaires optimisés

Abstract

This study evaluated the impact of various chemical pretreatments (citric acid, ascorbic acid, NaCl, CaCl2, sucrose, glucose) and thermal pretreatments (blanching in hot water or steam) on the drying kinetics, quality, and rehydration capacity of five plant-based products: strawberries, apples, bananas, onions, and beets. The experiments were conducted using an indirect solar dryer to propose sustainable and energy-efficient preservation solutions. The results showed that pretreatments help accelerate the dehydration process, preserve the natural color of the products, improve texture, and enhance rehydration capacity. Citric acid proved effective in reducing enzymatic browning, while CaCl2 increased tissue firmness. Sugars, although slightly slowing down drying, improved flavor and texture. Blanching contributed to enzymatic inactivation and better microbiological hygiene. Each product reacted differently depending on its intrinsic composition: Strawberries retained their color better with citric acid; apples exhibited better firmness and a more pleasant texture after acid soaking; bananas preserved their sweetness due to sugaring; beets required blanching to achieve optimal texture; and onions showed improved behavior with combined acid/salt treatments.