Biodegradable Films: They Do a Body Good
Now here's a story you can really sink your teeth into: scientists from the U.S. Agricultural Research Service (ARS) have created biodegradable, milk-based and biofuel-derived protective films. By combining the milk protein casein with water and glycerol, a biofuel byproduct, Peggy M. Tomasula and her colleagues at the ARS Eastern Regional Research Center's Dairy Processing and Products Research Unit in Wyndmoor, Pennsylvania, were able to develop a water-resistant, edible film that can be used as a glossy, transparent coating for groceries and other products.
They used carbon dioxide as a solvent to isolate the casein from the milk "instead of harsh chemicals or acids, which can be difficult to dispose of," according to Tomasula. Carbon dioxide, a byproduct of the glucose fermentation reaction used to make ethanol, helps make the film more water-resistant and biodegradable.
Tomasula and her team decreased the size of the CO2-casein particles, which are formed when the carbon dioxide dissolves into the milk, to improve the films' appearance and protective properties. Doing so made them more glossy and improved their ability to block moisture and oxygen permeation. In addition to providing the usual benefits of food packaging, including protection from damage and exposures to moisture and oxygen, an extended shelf life and improved appearance, the films reduce waste, because they are made with renewable resources instead of fossil fuels.
Tomasula hopes that these benefits will help make biodegradable films an attractive alternative to more common, less eco-friendly, films.
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