Researchers at Brown University have developed an inexpensive coating to protect fruits and vegetables that is made from eggs that would otherwise be wasted. The micron-thick coating solves problems for the produce and its consumers as well as for the environment.
The coating relies on eggs that never reach the market. The U.S. produces more than 7 billion eggs a year. The supply chain rejects about 3% of them, typically because of shell damage, which means that more than 200 million eggs end up in landfills.
The coating is mostly made from egg, the rest consisting of nanoscale cellulose extracted from wood, a tiny amount of curcumin (the main active ingredient in turmeric that has antimicrobial properties), and a bit of glycerol for added elasticity. The coating is applied to produce by spraying or dipping. It shows a remarkable ability to resist rotting for an extended period comparable to standard coatings like wax, but without their shortcomings.
Along with being edible, the coating retards dehydration, provides antimicrobial protection, and is largely impermeable to both water vapor to prevent dehydration and to gas to prevent premature ripening. The coating is entirely natural, and it washes off with water. So, anyone sensitive to the coating, such as someone with an egg allergy, can easily eliminate it.
Lab tests of the coating studied its effects on strawberries, avocados, bananas and other fruits. All were seen to maintain their freshness far longer than uncoated produce.
The researchers are continuing to refine the coating. They are also considering other source materials. They chose egg proteins because there are so many wasted eggs, but it may be possible to make use of plant proteins instead to address the needs of vegan consumers.
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Egg-based coating preserves fresh produce
Photo, posted July 13, 2012, courtesy of Liz West via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.
