Note: Estimation of Sorption Isotherm and the Heat of Sorption of Quinoa (Chenopodium quinoaWilld.) Seeds

Abstract

A modified Guggenheim-Anderson-de Boer (GAB) equation of four parameters was obtained to adjust the experimental sorption data for washed quinoa seeds. From the original GAB equation, only the monolayer moisture resulted in a dependence-temperature parameter showing a negative exponential trend with the absolute temperature. The results of the statistical adjustment showed that the new four parameters GAB equation adequately represented the experimental data in the range of 20 to 30°C with a corrected correlation coefficient of 0.999. The sorption heat of washed quinoa seeds was estimated by combining the GAB model with the Clapeyron equation and it resulted approximately 32% higher than the sorption heat of pure water in the temperature ranges between 20 and 60°C for temperature and 0.003 and 0.30 for moisture content. Using Othmer method the ratio of latent heats varied from 1.18 to 1.0474 in the range of moisture content studied.