ABSTRACT
Fatty acids are designated in several different ways. Despite the alternative descriptions set out, many trivial names are still widely used. These names were often given before the chemical structure of the acid was elucidated and were frequently chosen to indicate the source of the acid. Palmitic acid (16:0) is the most widely occurring saturated acid. Saturated acids of chain length greater than 18 carbon atoms are present at low levels in a few seed oils and at higher levels only in a few uncommon sources. The C20–C30 members are often present in waxes. The glycosyldiacylglycerols form a class of glycolipids that are present in plants and in bacteria. Diacylglycerols are linked to one or more sugar units at the sn-3 position. They are usually rich in polyunsaturated C18 acids. The most common cyclic acids contain a cyclopropane, cyclopentene unit. Cyclopropane acids occur in bacterial membrane phospholipids and are mainly C17 or C19 acids.
