Experimental investigation and numerical modeling of the hydration operation of date fruits

Abstract

Hydration represents the main unit operation in the industrial thermal process of dry dates. In this work, Tunisian Deglet Nour dates were hydrated experimentally at a laboratory scale by using saturated air as it is commonly undertaken in industry. This study focuses on the modeling of this unit operation in order to control the moisture uptake phenomenon during processing. A physic-based simplified numerical model describing moisture transfer during hydration was implemented in COMSOL[Formula: see text]Multiphysics software. The model considers the real geometry of dates instead of approaching the fruits by simplified shapes. Moisture diffusivities of two types of Deglet Nour dry dates characterized by different maturation stages were estimated. Results showed a good agreement between experimental and numerically computed values of average moisture content. Moisture profile in dates flesh was computed numerically using estimated moisture diffusivities. The numerical model proposed in this work could be therefore employed as a predictive tool to simulate and optimize the hydration operation of dates.