University of British Columbia researchers have developed an edible seaweed-derived coating that kept strawberries fresh for at least four days at room temperature, according to a study published in the Journal of Agricultural and Food Chemistry. The agar-based innovation addresses a major supply-chain hurdle for the fresh produce sector, where the UN Food and Agriculture Organization reports that fruit and vegetables suffer the highest global food loss rate at 25.4 percent.
How the Edible Seaweed Coating Extends Produce Shelf Life
The protective layer relies on agar, a red seaweed-derived material commonly used as a thickener and vegan gelatin alternative. According to lead author and doctoral student Ivy Chiu, researchers combined agar with zinc and tannic acid, a plant compound found in tea and grapes. These ingredients self-assembled into microparticles that form a clear, edible barrier when produce is dipped into the solution.
In tests, coated strawberries stored without refrigeration stayed mould-free for at least four days and lost less than half as much water as untreated fruit. They also remained firmer while retaining higher levels of vitamin C and antioxidants. Refrigerated coated berries maintained freshness for at least six days. By comparison, untreated room-temperature strawberries developed mould within two days, and refrigerated untreated berries began deteriorating by day four.
Commercial Potential and Supply-Chain Impact
Senior author Dr Tianxi Yang, Assistant Professor in UBC’s Faculty of Land and Food Systems, noted that the technology reduces the fresh produce sector’s reliance on cold storage. “Our hope is to help keep produce fresh for longer throughout the food system,” Dr. Yang said. “If we can reduce spoilage during storage and transportation, we can reduce food waste while using less energy to preserve food.”
Did You Know? Fruit and vegetables experience a 13.3 percent loss rate between the initial harvest and retail stages alone, according to UN Food and Agriculture Organization assessments.
A life-cycle assessment associated with the research estimated a 14 percent lower carbon footprint than conventional refrigeration and roughly 85 percent lower freshwater ecotoxicity. Beyond strawberries, the team recorded preservation benefits in grapes for up to 14 days and apple slices for 24 hours. Laboratory tests confirmed antibacterial properties, and assessments using human intestinal cells showed no signs of toxicity. Consumers can rinse off most of the coating under tap water within two minutes.
Industry Context and Adoption Hurdles
The UBC development aligns with broader industry efforts to curb post-harvest deterioration. In June, University of Copenhagen researchers introduced an ethylene-capturing clay designed to slow ripening. Last year, Swedish start-up Saveggy began piloting an edible plant-based cucumber coating with retailers to cut down on plastic packaging.
While the UBC team achieved similar moisture-loss reductions after swapping laboratory-grade agar for commercially available food-grade alternatives, widespread commercial adoption faces hurdles. A recent review of edible coatings highlights that regulatory requirements, economic feasibility, sensory compatibility, and consumer acceptance can restrict industrial use. The UBC research team is currently testing the coating on additional fruits and vegetables while exploring ways to scale it for commercial food systems.
Frequently Asked Questions
How long do coated strawberries last at room temperature?
According to UBC researchers, coated strawberries stored without refrigeration remained mould-free for at least four days, outperforming untreated refrigerated fruit.
What is the edible coating made of?
The protective layer is made from agar—a red seaweed-derived material—combined with zinc and tannic acid.
Can consumers wash the coating off before eating?
Yes, consumers can remove most of the edible coating under tap water within two minutes.
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