Scientists Develop a Seaweed Coating to Extend the Freshness of Fruit.
University of British Columbia researchers developed an edible seaweed-derived coating that kept strawberries fresh for at least four days at room temperature, outlasting uncoated berries stored in a refrigerator.
Researchers at the University of British Columbia have developed an edible coating from agar, a substance derived from red seaweed, that kept strawberries fresh for at least four days without refrigeration. According to the university, coated berries outperformed uncoated ones kept in a fridge. The findings were published in the Journal of Agricultural and Food Chemistry.
Agar is commonly used as a vegan alternative to gelatin and as a thickener in foods such as puddings. The team, led by assistant professor Tianxi Yang and doctoral student Ivy Chiu, combined it with zinc and tannic acid, a plant compound found in grapes and tea. The mixture assembled itself into tiny microparticles that form a thin protective layer. Strawberries, grapes and apple slices dipped in the solution dried with a clear coating. "To our knowledge, no one had made an agar-based microparticle coating like this before," Chiu said.
Over four days at room temperature, coated strawberries lost less than half as much water as uncoated fruit, stayed firmer and kept more vitamin C and antioxidants. Untreated strawberries at room temperature began developing mould within two days, and most untreated berries in the fridge began to deteriorate by day four. Coated berries stored without refrigeration stayed mould-free for at least four days, while coated berries in the fridge stayed fresh for at least six. Grapes and apple slices also benefited, with improvements lasting 14 days and 24 hours, respectively.
The coating showed antibacterial properties and no signs of toxicity in tests with human intestinal cells. Most of it can be washed off with tap water within two minutes. A life-cycle assessment found a carbon footprint 14 percent lower than conventional refrigeration and about 85 percent lower freshwater ecotoxicity, largely because the coating reduces reliance on the electricity and refrigerants used in cold storage.
The team also swapped laboratory-grade agar for commercially available food-grade agar and reported consistent results. Researchers are now testing the coating on additional fruits and vegetables and studying how it could be scaled up and integrated into commercial food systems. "We wanted to find a simple alternative to cold storage," Yang said.
At a Glance
- Coated strawberries stayed mould-free for at least four days at room temperature, according to UBC researchers.
- Coated strawberries lost less than half as much water as uncoated fruit over four days.
- A life-cycle assessment found a 14 percent lower carbon footprint than conventional refrigeration.
- Grapes and apple slices showed benefits lasting 14 days and 24 hours, respectively.
- Most of the coating washes off with tap water within two minutes.
Sources
This brief was written by Brightside Report from the reporting linked above. Spot an error? Request a correction.