A fully degradable bioplastic made from shrimp shells may be the answer to the plastic issue that is trashing planet earth. An extra benefit is it “doubles the shelf life of food products.”
The natural polymer derived from crustacean shells like shrimp is called Chitosan. It is non-toxic, biodegrades quickly, is excellent for forming film, and has antimicrobial and antifungal properties. Grapefruit seed extract (GFSE) is an antioxidant possessing strong antiseptic, germicidal, anti-bacterial, fungicidal and anti-viral properties. A food packaging material made with Chitosan film fortified with GFSE slows fungal growth, doubling perishable food shelf life.
The United Nations World Resources Institute says almost one third of all world produced food is wasted. The new technology would cut the waste and guarantee food security globally by keeping food edible longer, particularly in produce which is hugely wasted often from transit. In addition to feeding more people, other benefits of the film would be environmental and economic.
Taking three years to develop at the National University of Singapore, the film prevents fungi and bacteria growth, is mechanically strong while flexible, and an effective ultraviolet light blocker slowing oxidation and deterioration. With superior properties to current food packaging synthetic polyethylene film, in laboratory testing bread samples lasted two times longer than those in synthetic packaging films.
Nofima, Norwegian Food Institute as a partner in an EU consortium project is also working on bacteriostatic packaging using natural chitin nanocrystals (chitin-nanofibrols-CN) from shrimp shells with the coordinator, Italian company Mavi, and four medium-sized EU companies and three research centers. “Chitosan waste exceeds 25 billion tonnes per year and is hazardous due to its high perishibility and polluting effect, both on land and at sea. So re-use and upcycling to higher value applications would establish an important step forwards toward resource efficiency.”
Chitosan has been shown to significantly maintain papaya fruit and in combination with acacia tree hardened sap called Gum Arabic, delays banana ripening. The Centre of Excellence for Post-harvest Biotechnology at Nottingham University’s Malaysia Campus is testing and developing packaging with natural materials to improve fresh fruit quality and shelf life to help stop waste. For example, they have enhanced phenolic content and delayed ripening in tomatoes and extended dragon fruit life up to 28 days.
Polyethylene-chitin (PE-chitin) and polyethylene-chitosan (PE-chitosan) films were compared for biodegradability speed to that of commercial biodegradable film with 6 percent corn starch by microbial cultures in a soil environment for six months. In the lab, only 46.5 percent of the starch was degraded compared to 73.4 percent of the chitosan and 84.7 percent of the chitin. In an open field, 100 percent of the chitin and chitosan were degraded compared to 85 percent of the starch.
In 1997, using a biodegradable chitosan-cellulose and polycaprolactone laminate as a film for modified atmosphere packaging (MAP) of produce was tested for temperature dependence of O2, CO2 and N2 gas permeability on shredded lettuce and cabbage. The gas composition coefficients simulated to optimal validated the MAP systems for head lettuce, cut broccoli, whole broccoli, tomatoes, sweet corn and blueberries. This is posted on Science Direct.
The Wyss Institute, noting the human-produced 300 million tons of plastic annually with only 3 percent recycled and 97 percent left in oceans and landfills harming the food chain and environment, has even developed a fully degradable bioplastic from shrimp shell chitin and chitosan that can be shaped into items like chess pieces. They state the potential for its use in “trash bags, packaging, and diapers that break down in just a few weeks while releasing rich nutrients that support plant growth.”
Great things can come in small packages like shrimp shells.