The results of this work indicate the potential of PL in developing films with unique characteristics and functionality. This study is expected to directly impact the Food Industry, by providing technical information that would allow the development which will be able to design protein films with unique characteristics and functionality. Such films could be primarily used for the manufacture of biodegradable packaging materials.
impact statement issue
The packaging and food industries have continuously joined efforts to reduce the amount of food packaging materials, both for cost effectiveness and environmental reasons. The latter has become increasingly important in recent years, hence the increased efforts to use biodegradable materials as a more environmentally-friendly alternative to synthetic packaging materials. Unfortunately, the physical properties of biopolymer films, such as protein films, are inferior to those of synthetic films. Cross-linking has the potential to improve the mechanical strength and barrier properties of protein films. Photo-induced polymerization uses light to initiate and propagate a polymerization reaction to form a linear or cross-linked polymer structure. The objective of this phase of the project was to explore the effectiveness of Pulsed Light treatment as a photo-polymerization technique for improving the structural and functional properties of protein films made out of casein, soy proteins and their mixtures.
impact statement response
In the past year we focused on exploring the ability of soy proteins, casein and their mixtures to form edible biofilms that could have a wide range of applications in the food industry. Native micellar casein (MCN) and soy protein (SP) powders were used to prepare both individual protein solutions and mixtures with 1:1 SP:MCN ratio. Films were prepared by casting from protein solutions and their mechanical properties, microstructure and moisture barrier properties were evaluated. The films were then treated with Pulsed Light (PL) in order to increase their mechanical strength by inducing cross-linking of the structure. PL treatment of casein films with up to 12 pulses increased surface smoothness and homogeneity, while higher levels of treatment caused structural cracking. PL treatment did not affect water vapor permeability of the films. For casein films with PEG (400) diacrylate, a significant increase in tensile strength was observed after PL treatment. The incorporation of PEG (200) diacrylate resulted in films with a porous microstructure, with interesting photo-patterning effects observed at high level of PL treatment.
impact statement summary
The packaging and food industries have continuously joined efforts to reduce the amount of food packaging materials, both for cost effectiveness and environmental reasons. The physical properties of biopolymer films, such as protein films, are inferior to those of synthetic films. The objective of this phase of the project was to explore the effectiveness of Pulsed Light treatment as a photo-polymerization technique for improving the structural and functional properties of protein films made out of casein, soy proteins and their mixtures. PL treatment of casein films with up to 12 pulses increased surface smoothness and homogeneity, but did not affect their water vapor permeability. For casein films with PEG (400) diacrylate, a significant increase in tensile strength was observed after PL treatment. The incorporation of PEG (200) diacrylate resulted in films with a porous microstructure, with interesting photo-patterning effects observed at high level of PL treatment. The results of this work indicate the potential of PL in developing films with unique characteristics and functionality.
