Whey protein coating aims for eco-friendly benefits in multilayer packaging
A whey protein coating is being developed as part of an EU project to replace existing polyethylene (PE) or petrochemical plastic coatings in multilayer packaging and enhance recyclability.
The coating system will be created based on renewable raw materials from agrofood waste and its application for extrusion coating cartons to produce packaging materials for solid and liquid foods.
The EU project, dubbed BioBoard, claims the barrier coating will be biodegradable and can be washed off from the substrate where it is applied using enzymatic detergents.
It will build on past research that shows whey protein coating can provide bio-degradable plastic layers that can replace existing plastic coatings in multilayer packaging and boost recyclability.
Project aim
BioBoard, which started in November last year and runs until the end of October 2015, aims to produce packaging materials from the extrusion of coating paper, paperboard and cardboard.
Current methods of using polyethylene (PE) or other petrochemical based coatings generally lead to complex structures causing difficulty in recycling, according to the project consortium led by Innovacio I Recerca Industrial I Sostenible (IRIS), based in Spain.
It said seven million tons of coated paper, paperboard and cardboard are manufactured annually worldwide and the standard PE coating contains about 20 mass percent.
The recycling process involves grinding, washing, flotation, cleaning and screening to recover the fibres and not all paper mills are equipped for handling resulting residues comprising up to 25% of aluminium and plastic.
High shearing during the recycling leads to a reduction of the fibres size and limits their reuse to less demanding applications.
Whey and potato base
The base material for the coating will be formulations based on proteins such as whey and residues from potato.
Around 50% of the 50 million tons of whey produced annually in Europe is discarded, said the consortium.
At least 200,000 tonnes of potato by-products are disposed in Europe each year, they added.
Dr Elodie Bugnicourt, BioBoard project coordinator from Barcelona-based IRIS, said that: “BioBoard stands in response to the current demand from producers of coated paper, paperboard and cardboard manufacturers for a bioplastic that will enable them to substitute much of the currently used synthetic coating without compromising the barrier properties of the resulting packaging laminates and overcoming the current challenge to the recycling of such packaging”.
