Evaluation of Models to Describe Sorption and Desorption Equilibrium Moisture Content Isotherms of Virginia-Type Peanuts

Abstract

ABSTRACT AKNOWLEDGE of the equilibrium moisture content of a biological material is essential for the efficient design and operation of systems for drying, wetting or storing the material. The equilibrium mois-ture content of a material in a given environment may be defined as the moisture content which the material would reach if exposed to the environment for an infinite period of time. Since several investigators in-cluding Babbitt (1945), Hubbard et al. (1957), Breese (1955), and Young and Nelson (1967), found a hysteresis between the equilibrium moisture curves for wetting and drying proc-esses, it is necessary to define both sorption and desorption equilibrium moisture content isotherms. The objective of this study was to experimentally determine sorption and desorption equilibrium moisture content isotherms for Virginia-type peanut kernels and hulls at various temperatures, to use the experi-mentally determined curves to eval-uate the parameters of several pub-lished equations for equilibrium moisture content, and to investigate the implications of parameter values on such physical and thermal proper-ties as surface area per unit mass of dry matter and heat of sorption or desorption of water by peanut components.