Determinación de propiedades térmicas de zanahoria blanca (Arracacia xanthorrhiza), melloco amarillo (Ullucus tuberosus), papa china (Colacasia esculenta) y achira (Canna edulis)

Abstract

Today, the large number of available foods creates a great demand for knowledge of thermal properties. These properties are important in any process of the food industry because they are related with costs, optimization and product quality. In this sense, the objective of the present study was to determine the thermal properties (specific heat, thermal conductivity and thermal diffusivity) of four Andean tubers (yellow melloco, white carrot, chinese potato and achira), both in whole tuber and in extract. The thermal properties were studied as a function of temperature. The specific heat was evaluated at 4 and 12 Celsius degrees, while the thermal diffusivity was monitored at 50 and 70 Celsius degrees. The specific heat was determined by the method of the mixtures and by differential scanning calorimetry, the thermal conductivity by the method of the probe and the thermal diffusivity by the method of the cylindrical object. As for the results, higher values of specific heat were observed in yellow melloco and achira keeping relation with the nutritional composition. While in thermal conductivity and thermal diffusivity higher values were found in yellow melloco and lower values in achira. On the other hand, the thermal properties exhibited higher values when the extracts were evaluated, due to the reduction of air spaces, density and small resistance to heat transfer in this type of food matrices. On the other hand, chinese potato has the highest gelatinization temperature, being the most resistant to high temperatures.