Convective drying of black rice grains (Oryza sativa L.): new mathematical modeling insights and thermodynamic properties

Abstract

The aim of this study was to investigate the thin layer drying of brown rice grains at different temperatures (35-75 °C), exploring its kinetics and thermodynamic properties. Black rice grains (30% b.u.) were subjected to convective drying, and the experimental data were subjected to analysis of theoretical, semi-theoretical and empirical drying models, and thermodynamic parameters were calculated. Increasing temperature accelerated drying, shortening the time required to reach moisture balance. The modified Page model modified by Cavalcanti-Mata showed excellent fit to the experimental data, standing out for its simplicity and effectiveness in describing the relationship between water content and drying time. The analysis of thermodynamic properties revealed that the activation energy increased with temperature, evidencing its influence on moisture removal. The observed variations in thermodynamic properties reinforce the importance of considering energy factors in drying. The results offer insights to optimize the black rice grain drying process, contributing to advances in the food industry and providing a basis for future research in the processing of agricultural products.