The term rancidity refers to ‘off’ odours and flavours resulting from lipid oxidation or lipolysis. Rancidity can occur in many products or ingredients during storage. It affects taste and odour, and can have an impact on nutritive value. There are two major causes of rancidity. One occurs when oil reacts with oxygen and is called oxidative rancidity. The other cause of rancidity is by a combination of enzymes and moisture.
Oxidative rancidity, one of the major causes of quality deterioration in foods, is caused by the oxidative deterioration of lipids by atmospheric oxygen. In this reaction, lipids oxidize through a complex series of reactions giving rise to a myriad of non-volatile and volatile compounds that are responsible for off-flavours even at concentrations in the parts-per-billion range.
The reaction (oxidative rancidity) is catalysed by heat, ultraviolet light, heavy metals and oxygen. Many of these factors are obviously present during food processing. Oxidative rancidity is best controlled by the addition of antioxidants and ‘oxygen scavengers’.
Oxidative rancidity
