Efecto de la temperatura y del poder de calentamiento en las propiedades térmicas de oca (Oxalis tuberosa), jícama (Smallanthus sonchifolius), mashua (tropaeolum tuberosum) y camote (Ipomea batatas)

Abstract

The knowledge of the food thermal properties is very useful, because they are essential dates for the planning of various thermal treatments, which are involved in the creation of industrial processes, equipment designs, process time estimation and production of food suitable for consumption and with a long commercial life. Therefore, the objective of this study was to determine the effect of temperature and heating power on the food thermal properties (specific heat, thermal diffusivity and thermal conductivity) of four types of Andean tubers (sweet potato, jicama, mashua and oca), whole and in extract. The effect of temperature was determined at 8 and 16 Celsius degrees for specific heat by the method of mixtures and for thermal diffusivity at 35 and 60 Celsius degrees by the cylinder method; while thermal conductivity the effect of the heating power at 7.5 and 9 volts was evaluated by the probe method. The thermal properties of the four tubers studied were affected in all cases by the chemical composition, the structural changes of the food, as well as the temperature and the heating power. Jicama presented the highest value of specific heat and thermal conductivity, due to the high-water content. While total solids have an inversely proportional relationship with thermal diffusivity, due to the internal resistance they exert to heat transfer. On the other hand, the three thermal properties studied have higher values when working with extracts, because heat transfer in liquids is predominantly carried out by convection.