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Modeling Heat Transfer During Blanching of Cubic Particles of Loche (Cucurbita moschata Duch.) and Potato (Solanum tuberosum L.) Using Finite Difference Method

Mauricio, Vidaurre‐Ruiz Julio, Francisco, Salas‐Valerio Walter
Journal of food process engineering 2017 v.40 no.3
Cucurbita moschata, Solanum tuberosum, aluminum, blanching, computer software, heat transfer, heat transfer coefficient, models, potatoes, pumpkins, temperature profiles, thermal diffusivity
The aim of this study was to model heat transfer during blanching of cubic particles of loche (Cucurbita moschata Duch.) and potato (Solanum tuberosum L.). The model included the variation of thermal properties based on temperature and the solution of the model was implemented by explicit finite difference method. Cube particles of 1 × 1 × 1 cm³, 2 × 2 × 2 cm³, and 3 × 3 × 3 cm³ were subjected to blanching at temperatures of 70, 80, and 90°C, each one, for 5 min. The heat transfer coefficient (h) was determined experimentally during heating of different sizes of aluminum cubes. The variation of the thermal diffusivity (α) was also determined according to the temperature increase, finding the minimum and maximum value of (α) for loche were: 1.55–1.61 × 10⁻⁷ m² s⁻¹ and for potato were: 1.40–1.46 × 10⁻⁷ m² s⁻¹. A computer program in Visual Basic language was developed. The program includes the variation of the thermal diffusivity with respect to the increase of temperature with a second degree polynomial function. Experimental temperature profiles were compared with simulated ones, showing that an efficient convergence was achieved (RMSE: 0.329–5.119°C) for cubic particle of both vegetables. PRACTICAL APPLICATIONS: The explicit finite difference scheme in three‐dimensions (3D) developed in this research can be used to simulate heat transfer during heating of cubic particles of vegetables with variable thermal properties. Thermal properties of Loche (peruvian pumpkin) was reported for the first time and can be used for design and optimization of processes involving heating.