Vol. 11(4), pp. 41-46, July 2019 DOI: 10.5897/JETR2017.0626 Article Number: 2FB56C361247 ISSN: 2006-9790 Copyright ©2018 Author(s) retain the copyright of this article http://www.academicjournals.org/JETR Journal of Engineering and Technology Research Full Length Research Modeling of the adsorption isotherm of Pleurotus ostreatus using Guggenheim-Anderson-de Boer (GAB) equation Monsurat Bello, Matthew Olusola Oluwamukomi* and Victor N. Enujuigha Department of Food Science and Technology, Federal University of Technology, Akure, Ondo State, Nigeria. Received 5 July, 2017; Accepted 21 August, 2017 Moisture sorption isotherms of Pleurotus ostreatus were determined at three different temperatures (10, 30 and 40) and relative humidity (6 to 88%), using standard static gravimetric method. The samples were used to determine the equilibrium moisture content and the data fitted to the Guggenheim- Anderson-de Boer (GAB) equation to describe the moisture adsorption characteristics within the water activity used for this study. Model parameters c, k and M o were derived. The GAB monolayer moisture values (M o ) were 0.179, 0.163 and 0.123 at 10, 30 and 40°C respectively. The c and k value decreased from 0.729 to 0.613 at 10°C and 19.455 to 18.551 at 30°C, and increased to 0.712 and 24.737 when the temperature was further increased to 40°C. The mean relative percent modulus (%E) were 1.318, 5.393 and 3.224% at 10, 30 and 40°C respectively. The r 2 values obtained varied between 0.980 and 0.997, indicating strong correlations between the experimental and predicted data; whereas the error values ranged from 0.007 to 0.017, showing very good fitness between the experimental moisture sorption and the modeled sorption. Thus, GAB model could be used to predict the moisture sorption behavior of P. ostreatus mushroom at the range of water activity used in this study. Key words: Pleurotus ostreatus, mushroom, Guggenheim-Anderson-de Boer (GAB) model, adsorption, isotherm, monolayer. INTRODUCTION Moisture sorption isotherms are useful thermodynamic tools in the determination of interactions of water and food substances, to provide information on food processing operations such as drying, packaging and storage (Rizvi, 1995). The oyster mushroom (Pleurotus ostreatus) is a Basidiomycete fungus belonging to the Polyporaceae family. This edible mushroom is widely used as a culinary ingredient and dietary supplement in Asia because of its enticing flavor and nutritional value (Hong et al., 2013; Tsao et al., 2013). Fresh mushrooms easily deteriorate because of their high moisture content and nutrient density. In terms of preservation, studies have increasingly focused on various processes for the drying of mushrooms (Cui et al., 2003). In order to *Corresponding author. E-mail: mukomi2003@yahoo.com. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License