Why compost food scraps when you can make concrete with them? It’s not quite that simple, but researchers have found a way to turn fruit and vegetable scraps into tough building materials that remain edible and tasty after their transformation.
The idea could help divert part of the food waste that makes its way to landfills. Roughly 1.3 billion metric tons of food is wasted annually around the world, according to the United Nations. This is costly but also harmful to the environment, since growing food consumes large portions of the world’s water and energy. Plus, organic scraps decomposing in landfills produce methane emissions that spur climate change.
Researchers have previously proposed making fuels from food waste. A team from the University of Tokyo wanted to find a creative way to use waste fruits and vegetables. “Our goal was to use seaweed and common food scraps to construct materials that were at least as strong as concrete,” said Yuya Sakai, an industrial scientist at the university, in a press release.
But they also wanted to see if they could maintain the flavor in the leftovers. So they vacuum-dried various scraps, such as bits of seaweed and cabbage leaves, and the peels of orange, onion, pumpkin, and bananas. Then they pulverized the materials into powders, which they mixed with water and seasonings to make pastes that they pressed in molds at high temperature. This hot-press method is typically used to make construction materials from wood powder.
The team will report their research in the Proceedings of The 70th Annual Meeting of The Society of Materials Science, Japan. The brightly colored materials they made turned out to be edible but also durable. Left exposed to air for four months, the materials did not lose appearance or taste, and resisted rot and insects. Fibrous Chinese cabbage leaves resulted in the toughest material, over three times as strong as concrete.
Whether the materials could really be used for construction remains to be seen, but they could perhaps find novel uses in packaging, or even toys. After all, if a kid is going to chew on their toys, you might as well pack some flavor and nutrition into it.
Source: The work will be published in the proceedings of The 70th Annual Meeting of The Society of Materials Science, Japan as “Development of Novel Construction Material from Food Waste.”