Processing and Validation of Whey-Protein-Coated Films and Laminates at Semi-Industrial Scale as Novel Recyclable Food Packaging Materials with Excellent Barrier Properties

Abstract

A biopolymer coating for plastic films was formulated based on whey protein, and its potential to replace current synthetic oxygen barrier layers used in food packaging such as ethylene vinyl alcohol copolymers (EVOH) was tested. The whey-coating application was performed at semi-industrial scale. High barrier to oxygen with transmission rate down to ranges of 1 cm3(STP) m−2d−1bar−1at and 50% relative humidity (r.h.) but interesting humidity barrier down to ranges of 3 g m−2d−1(both normalized to 100 μm thickness) were reached, outperforming most existing biopolymers. Coated films were validated for storing various food products showing that the shelf life and sensory attributes were maintained similar to reference packaging films while complying with food safety regulations. The developed whey coating could be enzymatically removed within 2 hours and is therefore compatible with plastic recycling operations to allow multilayer films to become recyclable by separating the other combined layers. A life cycle assessment was performed showing a significant reduction in the environmental impact of the packaging thanks in particular to the possibility of recycling materials as opposed to incinerating those containing EVOH or polyamide (PA), but due to the use of biosourced raw materials.

State of the Art in the Development and Properties of Protein-Based Films and Coatings and Their Applicability to Cellulose Based Products: An Extensive Review

“…The solvents used to prepare protein film-forming solutions are generally based on water, alcohol or mixture of water and alcohol or a mixture of other solvents. Most commonly, the solvent removal is generally achieved by hot air or a combination of techniques as it may lead to a differential protein structuring and therefore variable protein films properties [85]. Indeed, as previously mentioned, during film formation, covalent bonds leading to a three-dimensional network forming may occur which have an important effect on resulting properties.…”

“…Film properties of the formulations can be influenced or modified by the addition of lipids, salts and different plasticizers but also by chemical, biochemical or physical modifications. Whey proteins for film productions are kept into account in several recent research activities due to their good industrial potential especially as plastic lacquer and paper extruded coating [39,55,56,85,[141][142][143][144][145][146]. Rossi et al, prepared and investigated transglutaminase-crosslinked whey protein/pectin films [147].…”

“…As the two polymers have a different density the separation by flotation is particularly easy. The process is described by Bugnicourt et al [85].…”

“…While substituting the EVOH barrier layer, such approach was investigated by Bugnicourt et al [85] was shown to allow an optimized recycling approach. Interestingly the presence of the protein based layer in the system would allow improving the barrier properties of the packages, replacing petrochemical layers with natural ones and also improving their recycling, by separating the different material in post-consumer packages and introducing composting for the bio-based fraction.…”

Polyhydroxyalkanoate (PHA): Review of synthesis, characteristics, processing and potential applications in packaging

“…In recent years more and more biopolymers have been studied by researchers revealing a large range of possible sources from which they can be obtained and an increasing range of applications that bio plastic produced from them can fulfil. The possible sources range from different types biomass (Figure 1) including proteins (from animal and vegetal sources which are gaining interest due to their high functionality and excellent properties) [1] lipids and polysaccharides (e.g. starch and cellulose based biopolymers).…”