Oils and fats are very important constituents of the vast majority of food products. Lipids are often the carrier of the taste components, yet at the same time oils and fats are the principal cause of sensorial degradation.
Because most lipids are susceptible to oxidation, they will have a major impact on the sensorial shelf life. Oxidised lipids will form volatile reaction products that cause rancidity. Many measures can be taken to prevent the onset of oxidation. The use of natural or synthetic antioxidants is one of the most efficient ways to avoid the formation of rancid food products. Other important aspects in oxidation control are protective packaging and cold storage; however, these measures alone are rarely sufficient.
Another important aspect in controlling oxidation is the negative connotation many additives tend to have for the consumer. Traditional synthetic antioxidants such as butylated hydroxyanisole (BHA) and tertiary butylhydroquinone (TBHQ) are often no longer accepted. There is a general trend to keep the product label as simple and as clean as possible. In this respect, natural plant extracts that contain molecules with antioxidant activity can be used to tackle shelf life problems while remaining label-friendly.
Other processes like frying also leads to undesired chemical and physical changes that affect both the quality of the deep-frying medium and fried food. Frying, for example, is a complicated, multi-factor process where the frying oil undergoes a complex series of oxidation reactions. A natural antioxidant can be used to protect frying oil from deterioration.