Lipids in Flavor Formation

Lipids not only serve as a source of condensed energy, they also provide essential fatty acids as well as mouthfeel and other attributes to food. Flavor effect of lipids is related to the interaction of food components with one another as well as lipid breakdown products via their participation in Maillard reaction under high temperature conditions experienced during processing. These reactions occur during frying, grilling and other modes of heat processing of foods. In addition, lipids may contribute to the flavor of fresh foods via lipoxygenase-assisted oxidation. Lipoxygenases are present in plants such as soybean and in fish gills, among others; their interaction with cis,cis-1,4-pentadiene moieties of lipids leads to the formation of stereospecific products. Furthermore, breakdown of lipids under thermal or photooxidative conditions produces an array of products, all of which are odor-active and may contribute to off-flavor development in both raw and processed foods. In particular, aldehydes and other carbonyl compounds serve as indicators of flavor deterioration of many foods. In addition, lipolytic reactions provide another route by which flavor reversion of food lipids may occur, such as those in butter and dairy products.