Barrier and mechanical properties of milk protein-based edible films containing nutraceuticals

Calcium caseinate (CC) and whey protein isolate (WPI) films were prepared to contain 5 or 10% Gluconal Cal (GC), a mixture of calcium lactate and gluconate, or 0.1 or 0.2% alpha-tocopheryl acetate (VE), respectively. The pH and viscosity of film-forming solutions and the water vapor permeability and tensile property of the films were determined using standard procedures. CC and WPI films have the capabilities to carry high concentration of GC or VE, but some of the film functionality might be compromised. Adding VE to CC and WPI films increased film elongation at break, whereas incorporating 0.2% VE decreased WVP of CC films and tensile strength of both CC and WPI films. Incorporation of GC reduced the tensile strength of CC films (P < 0.05), with 10% GC decreasing both elongation at break and WVP (P < 0.05). These types of films may be used for wrapping or coating to enhance the nutritional value of foods. The concentration of GC and VE added to the films must be carefully selected to meet required water barrier and mechanical properties of the films depending on their specific applications.