Estudo da modelagem matemática e propriedades termodinâmicas na secagem da polpa de graviola em leito de espuma.

Abstract

The major problema ínvolving íiuits and perishables in general are related to the storage and detemiination of maturation point. The drying process has been used to reduce the water content of food products, hindering microbial growth, chemical and biochemical reactions and facilitating its storage. Foam-mat dtying is a process in which liquid or semiliquid feeds are transfomied unto stable foams by the incorporation of foaming agents and subsequently subjected to dehydration. The objective of this work was to study the mathematical modeling and thermodynamic properties in the drying of the graviola pulp in the coam bed, for the conditions oftemperatures 50 ' C, 60 ' C and 70 ' C using air circulating greenhouse. After the drying data were co]]ected, they were ana]yzed by the mathematica] models of Logarithm, Pane, Henderson and Pabis, Midillí and Kucuk Diffusion Approximation. The mode] that best üjt the experimental data was Page and the second best was Midilli and Kucuk for presenting the best determination coefficient (R2) and the lowest estimated average error describing satisfactorily the drying kinetics studied. Temperatura was the main controjlíng factor of the process. It was observed that increasing the temperature of the drying air caused the water removal rates of the product to increase, taking less time for the pulp to reach its thermodynamic equilibrium, and consequently the pulp took less time to reach its thermodynamic equilibrium.