Fractionation An oil or fat normally consists of a number of fractions, each of which has different physical characteristics. Fractionation is the separation of selected fractions with the object of obtaining a product with different physical characteristics from the original fat. The combination of fatty acids with glycerol to form glycerides is sometimes reversed resulting in the presence of uncombined or free fatty acids. These are usually found in crude oils and may be removed by neutralisation . Glyceride More strictly, triglyceride, which is an ester formed by the combination of one molecule of glycerol and three molecules of fatty acid.
Glycerides occur naturally in oils and fats.
High Stability Oil An oil which, by careful selection of base oils and processing conditions, has a high oxidative stability yet retains the liquidity of a conventional vegetable oil. Hydrogenation Oils and fats which contain unsaturated fatty acids may have these changed to saturated acids by combination with hydrogen. This results in a higher melting point . Hydrolytic Rancidity Hydrolytic rancidity is a type of deterioration of oils and fats which results in the formation of free fatty acids which may be detected by a harsh flavour and increase in acid value. Hydroxyl Group A group which is made up of oxygen and hydrogen and which allows combination with acids to take place.