MODELING OF THE HEATING AND COOLING INTERNAL RATES IN FRUITS. CASE: MEXICAN LIME

Abstract

Heating and cooling treatments are frequently applied to harvested fruits to extend their shelf life. In both cases it is fundamental to know the time required to reach certain temperature at the center of the material. In this work we developed a reliable methodology to determine the heating or cooling time in fruits and for providing elements that allow improving their postharvest management. The mexican lime [Citrus aurantifolia (Christm.) Swingle] fruit was taken as study subject. A modeling of the heat conduction and convection mechanisms occuring inside the fruit and between it and the external environment, was developed. Models determined a thermal diffusivity coefficient of 10.2×10^-8 m² s^-1 and a thermal convection coefficient ranging between 19 and 58 W m^-2 °C^-1. The models predicted that the time for temperature conditioning is minimal if the air in contact with the fruit is moving at 3.7 m ^s-1.