Researchers at the University of British Columbia have developed an edible coating made from seaweed-derived agar that can help strawberries stay fresh longer without constant refrigeration. In tests, strawberries treated with the thin layer remained free of mould for at least four days at room temperature.
The formula combines agar with tannic acid and zinc, creating a transparent coating that forms on the fruit after dipping and drying. According to the team, the layer helps reduce moisture loss, keeps berries firmer, and adds antibacterial protection against spoilage-causing microorganisms.
The clearest results came from strawberries. After four days at room temperature, untreated berries lost about 30.59% of their weight, while coated berries lost 13.36%. The coated fruit also retained more firmness and preserved more vitamin C and antioxidant compounds. Similar benefits were observed in grapes, where freshness lasted up to 14 days, and in apple slices, where the coating extended shelf life by about 24 hours.
The researchers say the coating is thin, tasteless, and easy to remove with a short rinse of tap water. They also tested food-grade agar and found that the effect remained strong, pointing to possible real-world use in food handling and transport.
A life-cycle assessment suggested the approach could offer a lower-carbon alternative to conventional refrigeration, especially by reducing energy demand in storage and shipping. While the technology does not replace cold storage entirely, it may become a practical tool for reducing food waste and improving freshness across supply chains. The study was published in the Journal of Agricultural and Food Chemistry. In the future, such coatings could help make fresh produce distribution more efficient and sustainable.
