Dairy proteins could have packaging potential
ARS researcher Peggy Tomasula, in a new publication from Woodhead Publishing Dairy-Derived Ingredients: Food and Nutraceutical Uses, evaluates the latest research and development work on films made from dairy proteins, with an emphasis on those based on casein and whey, the major proteins found in milk.
Edible films and coatings made from food grade proteins and carbohydrates are an untapped source of renewable material, argues Tomasula, who is based at the ARS Eastern Regional Research Center where scientists are focused on developing such biodegradable dairy-based films as alternatives to oil based materials.
Most food packaging consists of multilayer films that are thin, continuous sheets of synthetic polymers. And Tomasula reports that edible films and coatings have the potential to replace one or more of these polymeric film layers to facilitate recycling.
With growing consumer and retailer concern about the waste generated during the manufacture of multilayer packaging, there is a need for viable, biobased packaging with good barrier proteins, she states.
The publication reports that, as a dairy ingredient, casein shows good adhesion to different substrates. But while casein is an excellent barrier to oxygen, carbon dioxide, and aromas, it is a weak barrier to moisture.
It also notes that because the water-soluble nature of those proteins poses a challenge, much of the research on edible casein films to date is directed toward improving their water-vapor-barrier properties but whey has been found to act as a good moisture-barrier film.
The ARS scientist also reveals that current research is looking at ways in which edible films could carry antimicrobials and thus be used on the surface of foods to prevent bacterial growth.
Research into the use of dairy proteins for edible films arose from the need to utilize excess surplus dairy proteins and efforts have been primarily focused on improving their mechanical and barrier traits but Tomasula argues that future research into dairy based films must extend to their production on a large scale basis to bolster shelf-life and food application evaluation.
WHEYLAYER, an EU funded three year project which was initiated in 2008, aims to develop whey protein-coated plastic films to replace expensive polymers and increase recyclability by replacing currently used synthetic oxygen-barrier layers with whey protein.
The researchers point out that replacingchemical based plastics with a natural by-product would safeguard the performance and enhance the recyclability of substrate film, thus adding huge value for the European packaging and food industries.