both the desired texture and improved keeping
qualities. There are several ways to do this,
the simplest and most common being to
saturate the unsaturated fatty acids
artificially. This process is called
hydrogenation, because it adds hydrogen
atoms to the unsaturated chains. A small
amount of nickel is added to the oil as a
catalyst, and the mixture is then exposed to
hydrogen gas at high temperature and
pressure. After the fat has absorbed the
desired amount of hydrogen, the nickel is
filtered out.
Trans Fatty Acids It turns out that the
hydrogenation process straightens a certain
proportion of the kinks in unsaturated fatty
acids not by adding hydrogen atoms to them,
but by rearranging the double bond, twisting it
so that its bend is less extreme. These
molecules remain chemically unsaturated —
the double bond between two carbons remains