Fats are part of a class of organic compounds called lipids.
In cooking, oils often refers to substances called fats that are highly hydrophobic (i.e., mix poorly with water); unlike other fats, oils are liquid at room temperature. Fractionated and hydrogenated oils are both altered forms of natural fats.
Types
Most natural fats are a mixture of different types of a molecule called a triglyceride. Triglycerides consist of a molecule called glycerol bonded to three fatty acid chains, so that the overall shape of the triglyceride is a little like an uppercase letter E. Each fatty acid is a chain of carbons bonded to hydrogen atoms on either side. A carbon atom may be double-bonded to one of its neighbors, in which case it will only have one hydrogen attached to it, or it may be single-bonded to both of its neighbors, in which case it will have two hydrogens. Fats in which all the carbons in the chains are single-bonded are called saturated fatty acids, while fats in which at least one of the carbons is double-bonded are called unsaturated.
Function
Because of the double-bonded carbons, unsaturated fats have kinks in their fatty acid chains, which makes unsaturated fats more difficult to pack together; consequently, unsaturated fats are more likely to be liquid at room temperature as a general rule. Manufacturers will sometimes separate out the different components of an oil to extract the type most useful for a particular product or process; this technique is called fractionation. Manufacturers may also use a chemical process called hydrogenation to convert unsaturated fatty acids into saturated fatty acids.
Considerations
Unlike fractionated oils, hydrogenated oils have been chemically altered by adding additional hydrogens to make them more stable at room temperature. A fractionated oil may be saturated or unsaturated, depending on what components a manufacturer chooses to extract during the fractionation process.
Tags: fatty acid, fatty acids, room temperature, unsaturated fats, acid chains, case will