By Blake Jackson
Researchers at Penn State have made a advancement in sustainability by combining milk protein and plant-derived cellulose to create ultra-fine nanofibers with potential uses in biodegradable and edible food packaging.
Using electrospinning a process that applies voltage to transform a liquid solution into extremely thin fibers the team merged casein, a milk protein, with hydroxypropyl methylcellulose (hypromellose), a cellulose-based compound from plants, to produce fibers about 1,000 times thinner than human hair.
These fibers were then formed into mats that could serve a variety of sustainable applications. “In a proof-of-concept study, we demonstrated the successful fabrication of stand-alone casein-rich electrospun mats,” said team co-leader Federico Harte professor of food science in the College of Agricultural Sciences. “Protein-based electrospun nanofibers are highly sought after for their potential use in tissue engineering, biomedical applications such as wound dressings, and emerging roles in edible packaging, offering sustainable food preservation and safety solutions.”
The research revealed that the combination of casein and hypromellose could be electrospun effectively at cellulose-to-casein ratios up to 1:4.
However, the mats with the fewest imperfections and the greatest surface area qualities crucial for food packaging were made from a solution with a 1:12 cellulose-to-casein ratio.
A notable discovery was that at 100% humidity, the fiber mats chemically reacted with moisture and transformed into clear films, making them ideal candidates for food wraps.
“Casein has a long history of use as a material for both food and non-food uses,” said team co-leader Gregory Ziegler, distinguished professor of food science, explaining that the protein can enhance food textures and nutritional values, as well being used in the production of glues, paints, paper coatings, cosmetics and pharmaceuticals. “This research adds to its utility by giving a new form: nanofibers.”
Previously, the team experimented with casein alone and combined with carrageenan, a red seaweed-derived food additive, but those mats were weak and brittle. The addition of hypromellose provided the necessary strength and flexibility.
“Our early efforts using casein alone clearly showed that we needed to improve the mechanical properties of the mats,” Harte said. “We eventually decided to add hypromellose because we thought that an interaction between casein and cellulose would optimize mechanical properties in these mats.”
Future research will explore applications for these edible nanofibers in food packaging and filtration technologies.
Photo Credit: penn-state-college-of-ag-sciences
Categories: Pennsylvania, Education