Researchers at the Institute of Industrial Sciences at the University of Tokyo are reusing food waste to make materials with bending strength comparable to concrete that still taste good.
Institute of Industrial Sciences, University of Tokyo
TOKYO, JAPAN – Most people don’t think much about the leftover food they throw out; However, researchers at the Institute of Industrial Sciences at the University of Tokyo have developed a new method to reduce food waste by recycling fruit and vegetable waste into sturdy building materials.
Global industrial and household food waste amounts to hundreds of billions of pounds per year, much of which is edible waste, such as the peels of fruits and vegetables. This unsustainable practice is both expensive and unfriendly to the environment, which is why researchers have sought new ways to recycle these organic materials into useful products.
“Our goal was to use algae and food scraps to build materials that are at least as strong as concrete,” says Yuya Sakai, lead author of the study. “But since we were using edible food waste, we also wanted to determine if the recycling process had an impact on the flavor of the original materials.”
The researchers borrowed a concept of “hot pressing” which is typically used to make building materials from wood powder, except they used vacuum-dried and pulverized food scraps, such as algae, cabbage leaves and orange, onion, pumpkin and banana peels as the constituent powders. The processing technique was to mix the food powder with water and seasonings, then press the mixture into a mold at high temperature. The researchers tested the flexural strength of the resulting materials and monitored their taste, smell and appearance.
“With the exception of the pumpkin-derived specimen, all of the materials exceeded our target for flexural strength,” says Kota Machida, a senior collaborator. “We also found that Chinese cabbage leaves, which produced a material more than three times stronger than concrete, could be mixed with the weaker pumpkin material to provide effective reinforcement.”
The new sturdy materials retained their edibility, and the addition of salt or sugar improved their taste without reducing their strength. In addition, the durable products were resistant to rot, fungi and insects, and did not undergo any appreciable change in appearance or taste after exposure to the air for four months.
Since food waste is a global financial burden and an environmental concern, it is crucial to develop methods for recycling food waste. The use of these substances to prepare materials strong enough for construction projects, but which also retain their edible nature and taste, opens the door to a wide range of creative applications from a single technology.
The work will be published in the Proceedings of the 70th Annual Meeting of the Society of Materials Science, Japan under the title “Development of Novel Construction Material from Food Waste”.
– This press release was originally issued on the website of the Institute of Industrial Sciences at the University of Tokyo. It was edited for style