Water Sorption Thermodynamic Behavior Of Whey Protein Isolate/ Polyvinyl Alcohol Blends For Food Packaging

Publication date: Available online 24 January 2020Source: Food HydrocolloidsAuthor(s): Bruna Rage Baldone Lara, Marali Vilela Dias, Mario Guimarães Junior, Paulo Sérgio de Andrade, Bruna de Souza Nascimento, Laura Fonseca Ferreira, Maria Irene YoshidaAbstractIn food packaging systems, moisture content influences chemical and physical film properties, also determining processes such as food spoilage, and properties of food texture and crispiness level. The study of water permeation and sorption processes of new materials intended to be used as packaging is very important to determine the best application conditions and to predict the film behavior under different moisture conditions inside and/or outside the packaging. In order to determine the suitable temperature and water activity (aw) application conditions for whey protein isolate (WPI)/polyvinyl alcohol (PVOH) blends as food flexible packaging, water permeation and water sorption thermodynamic behavior of these materials were evaluated. WPI/PVOH films and blends had solubility preponderant over the diffusion on the water permeation process. Water sorption experimental data were well described by the GAB model, and curves showed a more expressive increase of water sorption at aw> 0.75, with lower equilibrium moistures (Ye) at room than at chilled temperatures. Differential enthalpy decreased and differential entropy increased by the Ye gain, and the occurrence of enthalpy-entropy compensation was confirmed with enthalpy...
Source: Food Hydrocolloids - Category: Food Science Source Type: research