By Eric Onstad

Istanbul - Your toddlers have just munched and swallowed their crayons. But don't panic, say "bon appetit"! The colouring sticks are made from healthy soybeans.

United States farming groups are counting on new products such as edible crayons to eat up a bigger proportion of soybean production and boost prices, which are in danger of sagging as global output rises.

Soybean output in Latin America is due to surge in coming years, but researchers are busy concocting new uses for soybeans, ranging from paint to adhesives in addition to a growing biofuel market, a conference heard on Tuesday.

"There is huge soy production and the result is driving the market down," researcher John Cherry of the US Agriculture Department (USDA) told an edible oils conference in Istanbul.

"There is quite an effort in the US to push soybeans into the non-food market."

Use of soybeans outside of the traditional foods market has grown in recent years to absorb about four percent of the total US crop, up from two to three percent, but industry groups aim to push that up to 15-20 percent by 2020, said Cherry.

Soybeans are crushed into vegetable oils for cooking, soymeal that is mainly fed to animals and is also processed into protein sources such as vegetarian foods.

Biodiesel fuel, which mainly uses soyoil as a raw material, is already a burgeoning market in the United States, with production jumping from two million litres in 1999 to 95 million litres last year and forecast to increase to 130-140 million this year, the conference heard.

A big selling point for many of the new products is that they are environmentally friendly in contast to petroleum-based competitors. But they are generally more expensive, appealling to a limited market of green consumers willing to pay a premium.

A much cheaper use for soybeans has been discovered, however, using treated soybean hulls to filter out harmful metals such as cadmium, copper, lead and zinc from water.

A special process using citric acid and heat treatment turns the hulls into a product that outperformed expensive ion exchange resins in recent tests, said another USDA researcher, Wayne Marshall.

The production cost of the treated hulls was $1,17 (about R12,50) per kg in contrast to the resins that sell for $5-$40, he added.

Several companies and groups are interested in exploiting the new technology, including the port district of the US city of Seattle, which wants to remove harmful metals from runoff water before it ends up in a collection lake.

Another group from Iowa State University has developed soy protein-based adhesives, one of which was recently granted a US patent, the conference heard.

Some of the adhesives are used to make composite wood substitutes from fibre including cornstalks, wheat straw and waste from manure and paper manufacturing.