DRYING KINETICS OF CASHEW TREE BARK – Anacardium occidentale L.: MATHEMATICAL MODELING AND THERMODYNAMIC PROPERTIES

Abstract

The cashew tree (Anacardium occidentale L.) has a very large cultural and socioeconomic impact in tropical areas such as the North and Northeast of Brazil due to its fruit, pseudofruit and for having chemical and biological properties such as antioxidants, anti-inflammatory and antifungal properties, among others. present in this species. The present work aimed to study the drying kinetics of the cashew bark, as well as to apply mathematical models, thus observing their behavior. In addition to calculating the main thermodynamic properties such as: effective diffusivity, enthalpy, entropy and Gibbs free energy. The experimental tests were carried out at the Laboratory of Storage and Processing of Agricultural Products (LAPPA), Laboratory of Food Engineering (LEA) and Laboratory of Renewable Energy Sources (LABFREN). The cashew husks were dried at three different temperatures (50, 60 and 70 ºC) of drying air in a convective dryer with a fixed air speed of 1m/s. The Diffusion Approximation mathematical model was the one that most suited the data on the drying kinetics of the cashew peel, presenting high values ​​for the coefficient of determination (R² > 0.99). The effective diffusivity ranged from 8,89×10^-10m²s^-1 a 1,53×10^-9m²s^-1, the activation energy obtained a value of 25.1041 kJmol^-1. The change in Gibbs free energy increased with increasing temperature and was considered a non-spontaneous process, while enthalpy and entropy decreased.