This 3-ingredient film made from food waste may actually beat regular plastic packaging?

A new film that can be made from widely-available food waste is as effective as conventional plastics at shielding food from moisture and oxygen, its inventors say. The novel material was made by combining cellulose from wood pulp and chitin from crustacean shells or mushrooms, and builds on the team’s previous research to develop an alternative to petroleum-based plastic that can extend the shelflife of fresh produce.

In their ten years of work so far, they have made progress, developing materials that have become successively stronger and less permeable. However, they’ve battled to overcome one significant hurdle, which is that as humidity rises, the material they’ve invented becomes more permeable to both oxygen and water, threatening the contents within.

This time they tried a different approach, first of all adding a new ingredient, citric acid, to the mixture, and combining the three ingredients using a method called ‘crosslinking’, which bonds elements tightly to form a dense network. “Cross-linking has been shown to be effective in controlling moisture sensitivity of biopolymers at high humidity, generally by reducing swelling in the presence of water vapor,” they explain in their research.

The result of this three-part cellulose-chitin-citric acid matrix was a fine plastic sheet, suitable for covering food. Next, they needed to test out the resilience of this film-like material, by exposing it to varying degrees of humidity and heat. .IRPP_ruby , .IRPP_ruby .postImageUrl , .IRPP_ruby .centered-text-area {height: auto;position: relative;}.IRPP_ruby , .IRPP_ruby:hover , .IRPP_ruby:visited , .IRPP_ruby:active {border:0!important;}.IRPP_ruby .clearfix:after {content: "";display: table;clear: both;}.IRPP_ruby {display: block;transition: background-color 250ms;webkit-transition: background-color 250ms;width: 100%;opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: #eaeaea;}.IRPP_ruby:active , .IRPP_ruby:hover {opacity: 1;transition: opacity 250ms;webkit-transition: opacity 250ms;background-color: inherit;}.IRPP_ruby .postImageUrl {background-position: center;background-size: cover;float: left;margin: 0;padding: 0;width: 31.59%;position: absolute;top: 0;bottom: 0;}.IRPP_ruby .centered-text-area {float: right;width: 65.65%;padding:0;margin:0;}.IRPP_ruby .centered-text {display: table;height: 130px;left: 0;top: 0;padding:0;margin:0;padding-top: 20px;padding-bottom: 20px;}.IRPP_ruby .IRPP_ruby-content {display: table-cell;margin: 0;padding: 0 74px 0 0px;position: relative;vertical-align: middle;width: 100%;}.IRPP_ruby .ctaText {border-bottom: 0 solid #fff;color: #0099cc;font-size: 14px;font-weight: bold;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .postTitle {color: #000000;font-size: 16px;font-weight: 600;letter-spacing: normal;margin: 0;padding: 0;font-family:'Arial';}.IRPP_ruby .ctaButton {background: url(https://www.anthropocenemagazine.org/wp-content/plugins/intelly-related-posts-pro/assets/images/next-arrow.png)no-repeat;background-color: #afb4b6;background-position: center;display: inline-block;height: 100%;width: 54px;margin-left: 10px;position: absolute;bottom:0;right: 0;top: 0;}.IRPP_ruby:after {content: "";display: block;clear: both;}Recommended Reading:Chemists use bacteria to convert CO2 in the air into bioplastic Most strikingly, their experiments showed that at humidity levels of 80%—reminiscient of some tropical countries—the biobased film was even less permeable to oxygen than some mainstream plastic packaging like EVOH (ethylene-vinyl alcohol), commonly used to package fresh produce.

Also impressively, compared to polyethylene terephthalate, or PET, one of the most widely-used plastics in food packaging, the permeability to water vapor in the bio-based plastic was only slightly higher. And when contrasted with other bioplastic products like polylactic acid and cellulose acetate, the new material was at least two orders of magnitude more resistant to oxygen, the researchers say.

All this suggests a serious potential contender to conventional plastic packaging—and if it relies on food waste streams, this new material could help tackle that mounting global problem, too. What’s less clear from the study is how far it would go to tackle the problem of plastic pollution, given that the paper doesn’t explore how quickly this material biodegrades, and whether that can happen naturally, or if it would require more resource-intensive industrial composting processes.

The researchers do hint that it solves this problem, saying, “We’re using materials that are already abundant in nature and degrade there to produce packaging that won’t pollute the environment for hundreds or even thousands of years.” If that’s accurate, then alongside efforts to reduce the reliance on unnecessary single-use packaging in the first place, their invention could help shift the needle on plastic waste. Meredith et. “Transforming Renewable Carbohydrate-Based Polymers into Oxygen and Moisture Barriers at Elevated Humidity.” ACS Applied Polymer Materials. Image: ©Anthropocene Magazine