When you buy a bag of frozen shrimp, chances are they're already peeled, making a fast dinner a breeze (but negating the possibility for tasty homemade shrimp stock). Already-peeled shrimp, which are available both raw and frozen, are an increasingly common sight at the supermarket, and all those small, thin shrimp shells add up: each year, the US seafood industry produces 100 million pounds of shells from shrimp, crab, and crawfish processing combined.
Instead of letting all those scraps go to waste, a group of researchers at the University of the Basque Country in Spain is using them to develop a new type of food packaging that the group hopes might one day replace the landfill- and ocean-clogging plastic wrappers and containers that are made with unsustainable petroleum.
The group has experimented with using chitosan—a component of crustacean shells that is also, weirdly, a favorite supplement among dieters for its supposed fat-absorption properties—as a film to preserve foods. The group's head researcher, Itsaso Leceta, used the shrimp-derived film as a coating on baby carrots, and found that like plastic coatings, the chitosan film kept the carrots fresh. Plastic protects foods from microbes, and, interestingly, chitosan-based packaging does, too: the substance is naturally antimicrobial and antibacterial. It's used in agriculture to fight fungal infections in plants, in winemaking to prevent spoilage, and is sometimes even infused into bandages to help promote the healing of cuts and scrapes. Those properties, its researchers think, make chitosan-based packaging particularly appropriate for preserving food.
"Chitosan also has antimicrobial properties, so it is highly suited to the food industry, as it reduces the microbial load," Leceta told Science Daily.
Leceta noted that finding a replacement for plastic food packaging is a matter of urgent importance. Food containers and packaging—the majority of which are made from plastic—are the largest component of the municipal solid waste stream, clogging not only our landfills but also our oceans, where plastic kills seabirds, whales, sea turtles, and other ocean marine life; its pollutants might also be absorbed by fish and, eventually, the humans that eat those fish. Plus, like the gas in our cars, plastic is completely unsustainable; it's made from petroleum, which we're fast running out of.
And it's not just Leceta's group that's working on chitosan-based packaging. Last March, Harvard's Wyss Institute for Biologically Inspired Engineering announced its intention to research the technology. Researchers there said that chitosan is "the second-most abundant organic material on earth," easily harvested not just from shrimp and crabs, but also from copepods, plankton-sized crustaceans that are estimated to produce billions of tons of chitosan per year. The Harvard group has made cups and food containers from their chitosan-based material, and researchers noted that it could potentially be used to manufacture trash bags, grocery bags, and diapers, as well—three of the biggest offenders when it comes to both land and water pollution.
As abundant as chitosan is—and as promising as lab versions of food packaging made with it have been—it could be a while before your favorite brand of potato chips switches to seafood-based bags. "We have to go on conducting research," Leceta said.
One piece of good news when it comes to the potential packaging is that it will be safe for eaters with seafood allergies: the part of the shrimp that causes a reaction is found in the crustacean's muscles, not in its shell. No word, yet, on how the kosher community would feel about eating out of shrimp tupperware, though.