Main content area

Thermodynamic properties, kinetics and adsorption mechanisms of Swiss cheese bioaroma powder

Silva, Eric Keven, Borges, Soraia Vilela, da Costa, Joyce Maria Gomes, Queiroz, Fabiana
Powder technology 2015 v.272 pp. 181-188
Swiss cheese, adsorption, corn starch, encapsulation, enthalpy, entropy, maltodextrins, microparticles, models, powders, spray drying, temperature, water, water activity, water vapor
Water adsorption kinetics of Swiss cheese bioaroma microparticles were determined by a static method at 15°C, 25°C, 35°C and 45°C. This work used the Guggenheim–Anderson–de Boer (GAB) model to calculate thermodynamic properties of water adsorption. Additionally, this work predicted conditions for the stable storage of microparticles obtained through a spray drying encapsulation process with maltodextrin and modified corn starch (Capsul®) at a 1:1 (w/w) ratio. We evaluated the mechanisms that direct water vapor adsorption by studying enthalpy–entropy compensation. The product reached equilibrium phases after 120h of storage. The observed minimum values for the net integral entropy were indicative of maximized stability conditions of the product. At these conditions, water activity values ranged from 0.391 to 0.537, and the temperature ranged from 15°C to 35°C. An isokinetic compensation was confirmed for the adsorption phenomenon. This approach resulted in two zones, low and intermediate-high water activities. Under low moisture, the process was controlled by entropy; under intermediate-high moisture, it was driven by enthalpy.