Investigation of hygroscopic equilibrium and modeling sorption isotherms of the argan products: A comparative study of leaves, pulps, and fruits

•Study of hygroscopic equilibrium of argan leaves, pulps, and fruits.•Experimental determination of thermodynamic properties of argan products.•Modeling the adsorption and desorption isotherms of argan products.•The irradiation gamma treatment of the argan products.•Instant controlled pressure drop and drying processes of argan product. The aim behind this work is to demonstrate and validate a predictive experimental model of the thermophysical behaviors of the three argan products, leaves, pulps and fruits, using the experimental determination of sorption isotherms. They constitute an important information source to establish the stability of the products of argan and their conditions of conservation. The use of a suitable model for the analysis of the experimental data of sorption is a crucial step in the optimization and the design engineering setting on the scale of drying processes which are considered to be among the largest energy consumers in the chemical industry and agro-foodstuffs. The medicinal herbs are complex mixtures of chemical product that make it difficult to determine mass and heat mechanism. Digital simulations of the isotherms by the model of GAB (Guggenheim–Anderson–Boer) could not only correlate the equilibrium moisture content in food systems but also explain the different properties of sorbed water. Indeed, they are deemed of as helpful tools that allow better thermophysical valorization and lasting conservation. Net isosteric heat of sorption, total heat of wetting, differential entropy and spreading pressure were determined from the isotherms to define the energy associated with the sorption processes. The paper also investigates the impact of both the ionization (food irradiation) and the instant controlled pressure drop processes on water activity of the argan products.