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

• Published in: Journal of food engineering Vol. 275; p. 109868
• Main Authors: Viné, T., Flick, D., Bernuau, E., Broyart, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2020; Elsevier
• Subjects: Chemical and Process Engineering; Contact heating; Engineering Sciences; Food and Nutrition; Heat and mass transfer; Life Sciences; Modelling; Heat and mass transfer; Contact heating; Modelling
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2019.109868

Studies concerning the contact heating of food products remain relatively rare in the literature despite the importance of this mode of heat transfer in many operations (grilling, pan-frying). To 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. •Contact heating of sliced potato was studied at different heating powers, with oil or not.•A 2D model with moving boiling front adapted to contact heating was validated.•Oil below the product enhances heat transfer only at the beginning of heating.•Water evaporation and crust formation limit product heating by contact.