Mechanical and barrier properties of sodium caseinate–anhydrous milk fat edible films

Edible films were cast from solutions of sodium caseinate (NaCAS) and from emulsions of this protein with anhydrous milk fat (AMF). The moisture sorption isotherms, mechanical properties [tensile strength (TS) and elongation] and water vapour and oxygen permeabilities were determined for films based on NaCAS as a function of AMF concentration. AMF concentration significantly affected TS (P < 0.001) and elongation (P < 0.05). The increase of lipid content led to a loss of mechanical efficiency, but had little influence on water vapour barrier properties. No significant difference (P > 0.05) occurred between oxygen permeability of films at each lipid concentration.