Lipids warmed-over flavor from

Another processing procediue that could involve supercritical fluid extraction with CO2 is the preparation of flavor concentrates from meat lipids for use in mixtures of other natural precursors for the preparation of tynthetic meat flavor additives that serve bofii as antioxidants that prevent warmed-over flavor (WOF) in cooked meat diuing storage and enhance the flavor of the natural products. 

It has been known for many years that Maillard Reaction products can behave as antioxidants in food systems (13,14), and they have been shown to inhibit warmed-over flavor development in cooked meat which is caused by the autoxidation of lipids, especially phospholipids. There has been a significant amount of research examining the Maillard reaction products and intermediates from model systems which may have antioxidative properties. 

Presence and concentration of hemoproteins and free iron in meats from different species may also influence the rate of lipid autoxidation/degradation during the cooking and subsequent storage periods (13). Thus, development of off-flavors and unpleasant odors referred to as "warmed-over flavor" (2) depends primarily on the degree of unsaturation of lipid components of meats and somewhat on the level of iron-porphyrin materials present in the muscle. 

Although autoxidatlon of lipids in foods is generally considered as unwanted, certain products of lipid autoxidatlon at low concentrations are necessary to the characteristic odor and aroma properties of meats from different species (8.9.28 >. Therefore, the concentration and relative abundance of these chemicals in meat volatiles determine whether they play a desirable or an undesirable role in flavor characteristics of cooked meats. Thus, the origin of flavor and off-flavors developments, which are somewhat species-specific, are perhaps the same. So, in freshly cooked meats the specific flavor of meat which is species-specific develops and progression of autoxidatlon results in the formation of undesirable warmed-over flavor in cooked meats upon storage. 

Antioxidative Properties. When cooked meat is refrigerated, a rancid or stale flavor usually develops within 48 hrs. This character has been termed warmed-over flavor (WOF) and is generally attributed to the oxidation of lipids. Various synthetic and natural antioxidants have been used to reduce the development of WOF. Among the natural antioxidants used are the sulfur containing amino acid cysteine, and various Maillard reaction products. Eiserich and Shibamoto (Chapter 20) found that certain volatile sulfur heterocycles derived from Maillard reaction systems can function as antioxidants. 

Wilson, B.R. Pearson, A.M. Shorland, D.H. Effect of total lipids and phospholipids on warmed-over flavor red and white muscle from several species as measured by tribarbiouric acid analysis. J. Agric. Food Chem. 1976, 24, 7-11. 

Lipid components associated with meat fat, especially unsaturated aldehydes, play a significant role in species-characterization flavors. For example, ( ,Z)-2,4-decadienal exhibits the character impact of chicken fat and freshly boiled chicken (66). ( , )-2,6-Nonadienal has been suggested as the component responsible for the tallowy flavor in beef and mutton fat (63). 12-Methyltridecanal was identified as a species-specific odorant of stewed beef and provides a tallowy, beeflike flavor character (67). Aldehydes provide desirable flavor character to cooked meat, but they can contribute rancid and warmed-over flavors at high concentrations, resulting from autoxidation of lipids (68). 

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