Scientists at the Agricultural Research Service, the scientific research agency of the US Department of Agriculture, have developed a new process to produce foods with lower content of trans-fat acids, which may increase blood cholesterol levels. The new technique, developed by ARS chemist Gary R. List at the National Centre for Agricultural Utilisation Research in Peoria, IL, is called low-trans hydrogenation. By using a hydrogenation reaction with carbon dioxide, it makes a product with less than 10 per cent trans fatty acid content, suitable for use in margarine and other tablespread formulations. Margarine oils are usually prepared using hydrogenation or another conventional method, interesterification. Hydrogenation changes the chemical structure of oils to yield a margarine that does not melt at room temperature, but the hydrogenated product contains 10 to 30 per cent trans fatty acids. Interesterification rearranges the oil's fat molecules without adding hydrogen molecules to make a product with few trans fatty acids. Its drawback is that the process is more expensive than hydrogenation. List's low-trans hydrogenation alters the chemical bonds of the vegetable oil and produces oil with a much lower percentage of trans fatty acids. The researchers are currently seeking an industry partner to continue this development.