THOSE stubborn lumps you struggle to scrape off last night’s dinner plates are inspiring scientists to make new ultra-strong building materials. Researchers in Japan have created a concrete replacement out of food scraps and the new compound can be both edible and sweet-smelling.

Associate professor Yuya Sakai at the Institute for Industrial Science at the University of Tokyo and Kota Machida, whose research was part of his graduate studies at the university, have created building materials from scraps of cabbage, orange peel and onion skins, with four times the strength of concrete.

The earlier research by Sakai, a concrete engineer specializing in its recycling, resulted in a technique for combining recycled concrete powder and wood waste to form an improved material through heat pressing. That sparked interest in using other waste products. “A similar approach can be applied to not only wood, but also to vegetables and fruit, and that is what we did,” he said.

The professor’s research ideas rubbed off on Kota, one of his students. Kota adapted the heat pressing method, using lower temperatures (between 50 and 150 degrees Celsius), to produce materials four times stronger than concrete.

“It holds its original smell,” said Sakai. “You can smell orange if you make samples from oranges.” The material is nontoxic, and while it’s safe to consume, “it’s rather crunchy.”

The research has attracted interest from some product manufacturers, but further work is needed before it’s recognized for building purposes.

“In the future, we can develop more strength and materials from vegetables and fruit for real construction and structural materials,” said Kota. “For buildings, it will be a kind of future application,” said Sakai. “But so far, many companies have contacted us. They are interested in producing furniture, boxes and such small things.

“The bonding mechanism of these materials are not clarified completely yet, so we have to study these and prove them. That will be the next step. We also want to investigate a bigger variety of food scraps.”

The unique food recycling project can produce building materials in a variety of natural colors. He said students are interested in the research and that new members will join the laboratory next year.

Another useful element, Kota said, is the color of the materials they can produce. “It can retain its original color, and when we add other elements to the mix, we can control the color. I think it can meet a wide range of demands.”

Mango is their favorite food item for materials so far: “It tastes sweet, and it smells nice,” said Kota.

The paper, “Development of Novel Construction Material From Food Waste,” was published in May.(SD-Agencies)