Edible packaging getting closer to reality

Protein-based electrospun nanofibres have potential for applications in tissue engineering, biomedical applications such as wound dressings, and now other emerging food packaging applications.

In a new proof-of-concept study by researchers at Penn State, milk protein and cellulose derived from plants have been spun into thin fibres mats that could be used for wound dressings, cosmetics, filtration and even edible food packaging.

Using an electrospinning process, the liquid solution of milk protein casein with hydroxypropyl methylcellulose is forced under voltage into a cone shape to develop tiny nanofibres, 1000 times thinner than a human hair. These fibres are then fabricated into mats which could then be developed into biodegradable and edible food packaging.

In the study, which is available online, the researchers said the combination of casein enriched with hypromellose was electrospinnable up to a cellulose-to-casein ratio of one to four. However, the fibres spun from a solution with a cellulose-to-casein ratio of 1:12 provided the best outcome for the mats.

The researchers also discovered that at 100% relative humidity the fibre mats chemically reacted to moisture with ease, transforming into clear films that also hold potential for food wrap.

This study is the latest in a series of published research involving the electrospinning of casein. Previously, the research group assessed the electrospinning of casein alone and casein combined with carrageenan, a food additive derived from red seaweed and primarily used as a thickener, stabiliser and emulsifier in various food products. However, the mats produced in those studies contained weak and brittle nanofibres.

In this study, the researchers tested the idea of supplementing casein with hypromellose, which they thought could provide strength and flexibility to the protein and it appears that their hypothesis was right.

The team’s future research will further explore novel applications for the edible casein nanofibres, such as food packaging and filtration.

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