Egg White Protein Film Production Through Extrusion and Calendering Processes and its Suitability for Food Packaging Applications

The goal of this study was to produce a film made of egg white protein (EWP) through extrusion and calendering processes, the most common filmmaking processing technology, and to determine its potential for food packaging applications. The latter was assessed by measuring the mechanical, barrier, thermal, and optical properties; plasticizer leakage; and microbial resistance of the EWP film when exposed to specific combinations of relative humidity (RH) and temperature, and by comparing some of the results to those of commercial polylactic acid (PLA) film, the most commonly used bioplastic for food packaging applications. A transparent, continuous, thin, and uniform EWP film was produced with extruder-zone temperatures of 40 degrees C-50 degrees C-60 degrees C-70 degrees C-75 degrees C from feeder to die and with roller temperatures and speed set to 115-120 degrees C and 0.111rpm. The permeability, lightness, and transmittance of the resulting film were affected by temperature while the RH affected its thickness, tensile properties, permeability, color, transmittance, and glycerol loss. Compared to the PLA film, the EWP film was less breakable and flexible, and had a lower barrier to water and higher rigidity, thermal resistance, and barrier to oxygen. The two materials present similar transparency, lightness, color, barrier to ethanol, and sensitivity to RH. This study proves that EWP film can be produced through extrusion and calendaring processes and can be used as an alternative to other materials for food packaging applications where thermal resistance, rigidity, strength, barrier to oxygen, and avoidance of condensation are desired.

The authors thank the Hatch project 1007253 from the United States Department of Agriculture’s National Institute of Food and Agriculture (USDA NIFA). The authors also thank Abdhi Sarkar with the Michigan State University Center for Statistical Training and Consulting for her advice on the statistical analyses performed in this study. Dr. González-Buesa thanks the National Institute for Agricultural and Food Research and Technology (INIA) for a DOC-INIA research contract, and the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013), REA grant agreement no. 332201.

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