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.
See also: ::Maple View Dairy: Building Trust in Local Production, ::Milk price sees a-maize-ing hike, ::Ethanol Produced From Cheese, ::Omniflex and DuPont(TM) "Active Layer" Films: the Waterproofing Alternative for Gear,