Good Thinking

Rejected eggs used to keep fruits n' veggies fresh

Rejected eggs used to keep fru...
An apple is dipped in the egg-based coating
An apple is dipped in the egg-based coating
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An apple is dipped in the egg-based coating
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An apple is dipped in the egg-based coating
Yufei (Nancy) Cui prepares the coating, watched by Rice University research scientist and mentor Muhammad Rahman
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Yufei (Nancy) Cui prepares the coating, watched by Rice University research scientist and mentor Muhammad Rahman

Every year, millions of eggs are rejected for sale in supermarkets, while millions of fruits and vegetables spoil before being eaten. Scientists are now addressing both problems, utilizing rejected eggs to create a coating that keeps produce fresh longer.

The micron-thick, inexpensive, edible coating was developed at Rice University in Houston, Texas by undergrad students Seohui (Sylvia) Jung and Yufei (Nancy) Cui. They are working in the lab of materials scientist Prof. Pulickel Ajayan.

Approximately 70 percent of the coating consists of a biopolymer made from egg whites and yolks. The rest is composed of nanoscale cellulose fibers harvested from wood, a bit of curcumin derived from turmeric spice, and a small amount of glycerol – the cellulose forms a barrier that keeps water from evaporating from the produce, the curcumin has an antimicrobial effect, and the glycerol gives the coating some elasticity.

Yufei (Nancy) Cui prepares the coating, watched by Rice University research scientist and mentor Muhammad Rahman
Yufei (Nancy) Cui prepares the coating, watched by Rice University research scientist and mentor Muhammad Rahman

After strawberries, avocados, bananas and other fruits were dip-coated with the liquid, they were found to resist spoilage much longer than uncoated samples. More specifically, they ripened slower and resisted infiltration by bacteria, staying stiff and firm for a longer period of time.

Additionally, when free-standing films of the material were tested on their own, they proved to be highly flexible, resistant to cracking, and to exhibit a toughness similar to that of synthetic food-wrap films. And even though the coating is non-toxic, it can still be rinsed off of produce within a couple of minutes using tap water.

The scientists are now looking into replacing the egg content with plant-derived proteins, for vegans or people with egg allergies.

A paper on the research was recently published in the journal Advanced Materials.

Source: Rice University

3 comments
piperTom
I'm glad the coating is non-toxic, because the claim that it "can still be rinsed off of produce within a couple of minutes" is not worth much. In a typical kitchen, an invisible coating wouldn't get a couple of seconds under the faucet.
Signguy
A great use of otherwise wasted product, as well as non-toxic!
Kudos!
Calcfan
Good article, but you left out how much longer the coating keeps them fresh. Twice as long, 15 days? Its like saying there is a new faster car, but the speed is omitted. Without a measure there is much to say.