The idea of translating research from wound dressing to food packaging was born out of a collaboration with Philip Demokritou, the former co-director of the Center for Nanotechnology and Nanotoxicology (NanoCenter) at Harvard Chan School. The NanoCenter is a joint initiative between Harvard and Nanyang Technological University in Singapore.
“It turned out that wound dressings serve the same purpose, in some ways, as food wraps – to support tissues, protect against bacteria and fungi, and control moisture,” said Huibin Chang, a postdoctoral fellow at SEAS and first author of the study. paper.
To make the fibers food safe, the team turned to a polymer called pullulan. Pullulan is an edible, tasteless, natural polysaccharide commonly used in breath fresheners and mints.
The researchers dissolved the pullulan polymer in water and mixed it with a range of naturally occurring antimicrobial agents, including thyme oil, nisin and citric acid. The solution is then spun in an RJS system and the fibers are deposited directly on a food. The researchers demonstrated the technique by wrapping an avocado with pullulan fibers. The result looks like a fruit wrapped in a spider’s web.
The research team compared their RJS packaging to standard aluminum foil and found a substantial reduction in contamination from microorganisms, including E.coli, L. innocua (which causes listeria), and A. fumigatus (which can cause disease in immunocompromised people).
“The coating’s high surface-to-volume ratio makes it much easier to kill dangerous bacteria because more bacteria come into contact with antimicrobial agents than in traditional packaging,” said John Zimmerman, postdoctoral fellow at SEAS and co-author . paper.
The team also demonstrated that their fiber packaging increased the shelf life of avocado, a notoriously finnicky fruit that can go from ripe to rotten in hours. After seven days on a lab bench, 90% of unwrapped avocados were rotten, while only 50% of avocados wrapped in antimicrobial pullulan fibers rotted.
The wrap is also water soluble and biodegradable, rinsing without any residue on the surface of the avocado.
Make food more sustainable
This antimicrobial and biodegradable food packaging system is not the disease biophysics group’s first foray into making our food supply system more sustainable.
Parker’s group used their RJS system to grow animal cells on edible gelatin scaffolds that mimic the texture and consistency of meat. This technology has been authorized by tender fooda Boston-based startup that aims to combat the huge environmental impact of the meat industry by developing a new generation of plant-based alternative meat products that have the same texture, taste and consistency as real meat.
The laboratory’s latest innovations in food packaging could also enter commercial development soon. Harvard Technology Development Office has protected the intellectual property relating to this project and is currently exploring commercialization opportunities with Parker’s lab.
“One of the long-term goals of my research group is to reduce the environmental footprint of food,” Parker said. “We’ve achieved this by creating more sustainable food to now package food in a sustainable way that can reduce food waste.”
This research was co-authored by Jie Xu, Luke A. Macqueen, Zeynep Aytac, Michael M. Peters, Tao Xu, and Philip Demokritou.
It was supported by Nanyang Technological University–Harvard TH Chan School of Public Health Initiative for Sustainable Nanotechnology, under project number NTUHSPH 18003; the Harvard Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award number 1541959; and Harvard Materials Science and Engineering Research Centerunder grant numbers DMR-1420570 and DMR-2011754.