Soybean oil enters into trans fat free zone

The National Soybean Germplasm Collection in Illinois in the US recently received soybean genetic material, or germplasm, with higher monounsaturated fat concentrations than any other previously included in the collection.

Developed by scientists at the US government's Agricultural Research Service (ARS) Soybean and Nitrogen Fixation ResearchLaboratory, the new germplasm, called N98-4445A, will be 'a useful genetic resource for breeding mid-oleic soybean varieties suitable for different growing regions,'​ said the lead agronomist Joseph Burton.

Oil from the germplasm contains increased levels of oleic acid-a monounsaturated fat stable enough for use in salad dressings or frying oils without treatment by the hardening process called hydrogenation.

Hardening is achieved by chemically adding hydrogen to a chain of oil molecules. While hydrogenation serves as a stabiliser to make oils suitable in solid products such as margarines, breakfast bars, and baked goods, it also creates trans isomers, which are known as less healthy trans fats. "The new oil would likely be as stable as hydrogenated oils, but without the trans isomers,"​ said Richard Wilson, ARS's national program leader for Oilseeds and Bioscience.

"Oils based on this new line would likely not oxidise as quickly as other soybean oils," he added.​ According to ARS, the germplasm line's increased oleic acid level also correlates to a decrease in polyunsaturated fatty acids (PUFAs). PUFAs are liquid fats (such as linoleic and linolenic acids) that are known to cause off-odours and break down when oxidised during aging or frying.

'While commercial soy oils are 7 per cent linolenic acid, the new line has only 3 per cent of that highly unstable PUFA. In comparison, even a 4-per cent content might require some hydrogenation. Oils based on the new generation would fall below a critical cut-off point under which no hydrogenation is necessary,'​ said the scientists.

Market demand for trans fatty acids is on the up as food manufacturers call for alternatives to trans fats, created by a chemical process called hydrogenation in the production process for longer shelf life.

But linked to raised blood cholesterol levels and heart disease in animal fats, trans fats have come under fire from consumer organisations pressing the food industry to cut the ingredient out of foods.

Last year the US Food and Drug Administration (FDA) ruled that by 2006 all manufacturers will have to clearly label the levels of these fats in their foods.

While there are no such labelling rules in the European Union certain national governments are pushing for change. Last year Denmark became the first country in the world to introduce restrictions on the use of industrially produced trans fatty acids. Oils and fat are now forbidden on the Danish market if they contain trans fatty acids exceeding 2 per cent.

In October last year US biotech giant Monsanto announced, just as ARS has done this week, that it will develop a research platform to focus on reducing trans fats in soybean oil, and in time for the entry of the FDA rules.

The company said that it will apply conventional breeding techniques to produce a soybean low in linolenic acid. The process of hydrogenation reduces the amount of linolenic acid in soy oil and creates trans-fatty acids. According to Monsanto, this soybean would produce a soy oil that reduces the need for hydrogenation, and, in turn, could help reduce trans-fats in many foods and even eliminate trans-fats in some.