Warmed-over flavor development

Igene, J. O., and Pearson, A. M. (1979). Role of phospholipids and triglycerides in warmed-over flavor development in meat model systems. J. Food Sci. 44, 1285-1290. 

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. 

Cooked ground beef Grape seed extract Improve oxidative stability reduce warmed-over flavor development Ahn et al., 2002... 

Ahn et al., (2002) evaluated the effectiveness of selected natural antioxidants added to meat samples at levels of 0.02%, 0.05% and 0.1% to reduce warmed-over flavor development in cooked ground beef. They foimd that 0.1% grape seed extract reduced hexanal content by 97% after 3 d of refrigerated storage, while treated meat showed significantly lower TEARS values than control meat. These authors reported no adverse effects of this natural plant extract on flavor and aroma at the 0.02% level. 

Igene, J.O., King, J.A., Pearson, A.M., and Gray, J.l. 1979. Influence of heme pigments, nitrite, and non-heme iron on development of warmed-over flavor (WOF) in cooked meat. J. Agric. Food Chem. 27 838-842. 

Figure 2. Preparation and design of experiment to compare the effect of heme and non-heme iron on the development of warmed-over flavor. (Reproduced with permission from Ref. 16.)...

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. 

Development of rancidity and warmed-over flavor, a specific defect that occurs in cooked and reheated meat products following short-term refrigated storage, has been directly linked to autooxidation of highly unsaturated, membrane-bound phospholipids and to the catalytic properties of nonheme iron (Oelinngrath and Slinde, 1988 Pearson etal., 1977 Hultin, 1994). 

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. 

There is increasing evidence that degradation of proteins is associated with the development of the so-called warmed-over flavor . Selective methods to measure protein oxidation may be useful as a complementary approach in evaluating oxidative deterioration of meat products. The determination of protein carbonyls (as dinitrophenyl hydrazine derivatives) is now used for this purpose. More reliable methods are needed, however, to determine specific products of lipid oxidation and their interaction products acting as precursors of flavor compounds to establish the relative contribution of heme and nonheme iron to the development of rancidity in various meat products. 

Oxidative deteriorations of meat increase with increasing heating temperatures and heating time. However, above 100°C browning Maillard reaction products are formed at the surface of meat that inhibit lipid oxidation and the development of warmed-over flavor. This heat treatment changes the water-holding capacity and the appearance of the meat, which may not be desirable. 

If cooked meat is stored for a short time, e. g., 48 h at ca. 4 °C, an aroma defect develops, which becomes unpleasantly noticeable especially after heating and is characterized by the terms metallic, green, musty and pungent. This aroma defect, also called warmed over flavor (WOF), is caused by lipid peroxidation (cf. 12.6.2.1). The indicator of this aroma defect is hexanal, which increases as shown in Table 12.27. 

Igene, J. O., Yamauchi, K., Pearson, A. M., Gray, J. L, and Aust, S. D. Evaluation of 2-thiobarbi-turic acid reactive substances (TBARS) in relation to warmed-over flavor (WOF) development in cooked chicken. J. Agric. Food Chem., 33, 364-367 (1985). 

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