Henry Bradley patented oleomargarine in 1871. This butter substitute was touted for its health benefits — until more studies clouded the picture.
Margarine wouldn’t exist without butter, of course. From its inception, margarine was an attempt to mimic the taste and texture of butter. In the 1860s, Emperor Napoleon III offered a prize to the person who could produce an edible fat substitute for butter. Hippolyte Mege-Mouries, a French chemist, created oleomargarine, a combination of clarified beef fat, water, and a bit of tributyrin–a milk fat–to give it a buttery taste.
Mege-Mouries called it oleomargarine after the fatty acid then called margaric acid. It turns out that margaric acid (named after the Greek word for pearl–margarites–for its pearl-like luster) is actually a combination of stearic and palmitic acids, fatty acids often found in animal fats.
Fatty acids in oils are mostly monounsaturated or polyunsaturated. Oleic and linoleic acids, for example, have one or more double (olefin) bonds along the fatty acid chain. Because natural double bonds usually assume the cis configuration, where the olefin hydrogens are located on the same side of the chain, these fatty acids contain a bend of about 30°. Fatty acids with cis double bonds don’t pack well and are liquid at room temperature.
French and German chemists learned how to solidify liquid oil through hydrogenation. They heated the oil in the presence of a metal catalyst and pressurized hydrogen gas, causing hydrogen atoms to add randomly to the double bonds. Complete hydrogenation saturates all double bonds. Partial hydrogenation saturates some and converts others from cis to trans. In a trans double bond, the hydrogens are kitty-corner, which allows for compact packing of the fatty acid chains. The more complete the hydrogenation, the firmer the oil becomes–and the longer the shelf life. Oils turn rancid as double bonds oxidize in air.
Over the past century, margarine makers have favored partially hydrogenated oils–ones that remain soft enough for spreading on toast. To that semisolid fat base, they add a butter flavoring (buttermilk, whey, or a nondairy substitute), salt, emulsifiers (such as soy lecithin), a preservative like sodium benzoate or citric acid, some vitamin A to give it the nutritional value of butter, and a dash of yellow color (often ß-carotene).
Visit “What’s That Stuff” to learn more about the studies that clouded the picture for margarine.
Excerpted with permission, Chemical & Engineering News
Copyright © 2004 American Chemical Society