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Etude comparative des procédés de séchage couplés à la texturation par Détente Instantanée Contrôlée DIC, en termes de cinétique et de qualité nutritionnelle. Applications à la valorisation des déchets agro-industriels

Abstract : The present PhD work concerns the effect of thermo-mechanical texturing by DIC (Instantaneous Controlled Pressure-Drop) on fruit and vegetable drying. This pretreatment dramatically improves drying kinetics when the internal mass transfer coupled to the shrinkage of the product, is the limiting process. Indeed, the drying time decreased by 67% in the case of onion and 77% for blackcurrants, while the effective diffusivity Deff increased up to 246%, 795%, 336%, and 1223% for cranberry seed and waste, onion and blackcurrants, respectively. With these products, the saturated steam pressure generally has a significant positive effect on the drying kinetics.DIC treatment significantly improves the main nutritional and functional characteristics of the fruits and vegetables, with more available phenols and higher antioxidant activity. As thermal degradation is negligible, the DIC treatment involves micromechanical effect linked to the instant pressure drop, which allows cell to break and structure to be more porous such increasing the maximum extractable amount. Various physical, microstructural and functional characteristics of new textured material allow water interaction to be completely modified in terms of rehydration kinetics and capacity, sorption isotherm, microbiological and nutritional content... depending on operating DIC conditions, which can be optimized according to the consumer needs.
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Nsren Albitar. Etude comparative des procédés de séchage couplés à la texturation par Détente Instantanée Contrôlée DIC, en termes de cinétique et de qualité nutritionnelle. Applications à la valorisation des déchets agro-industriels. Autre. Université de La Rochelle, 2010. Français. ⟨NNT : 2010LAROS309⟩. ⟨tel-00567220⟩

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