Ricerc@Sapienza

Abstract: A non-isothermal moving-boundary model for food dehydration, accounting for shrinkage and thermal effects, is proposed and applied to the analysis of intermittent dehydration in which air temperature, relative humidity, and velocity vary cyclically in time. The convection-diffusion heat transport equation, accounting for heat transfer, water evaporation, and shrinkage at the sample surface, is coupled to the convection-diffusion water transport equation. Volume shrinkage is not superimposed but predicted by the model through the introduction of a point-wise shrinkage velocity.

We investigate and quantify the error in the estimate of water diffusivity resulting from the adoption of one-dimensional (1-d) models to describe the drying process of thin discoidal or long-thin cylindrical samples. Numerical results obtained with the 1-d and the 2-d moving boundary models recently proposed by Adrover, Brasiello, and Ponso (2019a, 2019b) are compared for different sample aspect ratios.

recently proposed moving-boundary model for food isothermal dehydration was applied
to analyze the dehydration kinetics of ellipsoidal cocoa beans, characterized by a moderate shrinkage
and a non-uniform initial distribution of water content between the core and the shell of the bean.
The aim is to predict the influence of air velocity and non-uniformity of the initial water distribution
on the dehydration rates, as well as the temporal evolution of the water content in the core and