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Drying of coating on bun bread: Heat and mass transfer numerical model

Cevoli, Chiara, Nallan Chakravartula, Swathi Sirisha, Rosa, Marco Dalla, Fabbri, Angelo
Biosystems engineering 2019 v.181 pp. 1-10
breads, coatings, drying, drying temperature, edible films, finite element analysis, heat, mass transfer, mathematical models, moisture diffusivity, solvents
The application of edible coating in bakery products could be a suitable alternative to maintain safety, textural and organoleptic characteristics during the storage. To achieve a continuous coating layer, the coating solvent should be eliminated by a drying process, avoiding the food internal dehydration. The main factors that influence the drying time of the coating are the temperature, thickness of the coating and the solvent concentration. In order to define the optimal drying time, numerical modelling could provide a suitable alternative to experimental techniques. In this study, finite elements models able to describe the heat and moisture transfer inside and on the surface of coated bun breads, as function of drying temperature, time and coating thickness were developed and validated. A good agreement was obtained between calculated and experimental data reporting RMSE of 0.05 and 0.04 kgwater kgsolid−1 for the samples dried at 25 and 60 °C, respectively. A relation between the optimal drying time, coating thickness and the drying temperature was determined (R2 = 0.981, 95% confidence bounds). The model could be used for other coating formulations and bakery products, simply by changing material properties and geometrical dimensions.