What Is Margarine?

Margarine was first developed in the nineteenth century as an alternative for butter. Early on it was a popular butter substitute for people who could not afford butter or to whom butter was not available. Margarine can be made from animal fats and/or vegetable oils; however, the bulk of margarine containing products today use vegetable oil based margarines. This is partly attributable to the relationship between a diet high in saturated fat in animal fat and the risk of heart disease. Plant oils tend to have fewer saturated fatty acids and do not contain cholesterol. More specifically, plant oils have much lower amounts of three types of saturated fatty acids (that is 16:0, 14:0, and 12:0), which are the SFAs that seem to be most associated with raised blood cholesterol levels.

Today, margarine from plant oils is made by adding hydrogen to unsaturated fatty acids in plant oils. Scientists called this process hydrogenation, during which some PUFAs are converted to MUFAs and some of the MUFAs are converted to SFAs (Table 5.4). This converts the liquid oil to semisolid or to solid fat. Hydrogenation occurs when the oils are heated up in a container and hydrogen gas is applied. The degree of change depends upon how much hydrogenation is allowed to take place. For instance, margarines that come in stick form are typically more hydrogenated than softer tub margarine.

Margarine is typically made by solidifying plant oils in a process called hydrogenation.

The most popular plant oil used for hydrogenation is soybean oil. Because of their relatively high content of MUFA and PUFA, margarines made from soybean, sunflower, safflower, olive, and cottonseed oils are perceived to be healthier than butter. However, when energy (heat) is applied to plant oils during hydrogenation, a small number of the cis double bonds can be converted to trans double bonds, which helps solidify the oil. In fact, conventional margarines have a higher trans fatty acid content than butter and typically the harder the margarine the higher the trans fatty acid level. Food companies have been working successfully over the past decade to alter their process for forming margarine to lower and eliminate the trans fat content, which is reflected on the food labels.