Experimental and numerical study of heat and mass transfer during contact heating of sliced potatoes

International audienceTo deal with this, kinetics of product water loss and temperature rise were recorded during contact heating of potato slices in order to examine the influence of the heating power and of the presence or not of an oil layer below the heated product. From the experimental data acquired, a 2D mathematical model based on a moving boiling-front approach was developed and validated allowing the determination of contact heat transfer coefficient values of 512.2 +/- 12.4 W m(-2).K-1 and 197.5 +/- 5.8 W m(-2).K-1 for experiments with and without oil respectively. The analysis of the simulation results showed that the overall heating of the product is limited by: (i) the evaporation of liquid water at the location of a boiling front propagating within the heated product and (ii) by the development of a dried region (crust) in the lower part of the product acting as a thermal insulating layer. It should also be noted that the determination of the contact heat transfer coefficient can become an incidental problem (especially for experiments with oil) since the thermal contact resistance is often much lower than the thermal resistance associated with conduction in the dried region of the product

Evolution of Moisture Distribution During Storage in a Composite Food Modelling and Simulation

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Effect of Temperature on Moisture Barrier Efficiency of Monoglyceride Edible Films in Cereal-Based Composite Foods

International audienceThe effects of temperature on moisture transfer within a composite food consisting of a sponge cake (SC) separated from a high moisture content agar gel (AG) by an acetylated monoglyceride (AMG1 and AMG2) film were investigated through moisture content profile experiments. A diffusion model was successfully used to predict moisture transfer within various composite foods (AG/SC, AG/AMG1/SC, and AG/AMG2/SC). The barrier efficiencies of the two hydrophobic films studied were reduced by temperature increase due to activation of diffusivity and equilibrium water sorption. Despite the low melting point of highly acetylated monoglyceride films, their barrier efficiency appeared to be less sensitive to temperature than monoglyceride films with a lower degree of acetylation. Consequently, in poor storage temperature conditions, these latter monoglyceride films seemed to be more effective in enhancing the shelf-life of the composite food studied here

Preventing Moisture Transfer in a Composite Food Using Edible Films: Experimental and Mathematical Study

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Modelling of Moisture Transfer in a Composite Food: Dynamic Water Properties in an Intermediate aw Porous Product in Contact with High aw Filling

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