Processing of patties after frozen storage led to a decrease of TBARS upon cooking and a subsequent increase during the following chilled storage (Table 2). High temperatures are believed to increase the damage caused by frozen storage in the cellular structure of the meat, resulting in exposure of the phospholipids to oxygen or release of other pro-oxidants, and, therefore, accelerate development of oxidative rancidity (Min & Ahn, 2005). However, in the present study, cooking led to a decrease of TBARS as a likely result of the combination of lipid oxidation products with other meat components such as proteins (Hidalgo et al., 1998). The persistent action of these pro-oxidants during the following chilled storage along with the dehydration caused by cooking probably led to a more effective collision between reactants, leading to the observed increase in TBARS values during the subsequent chilling (Fenemma, 1996). As for TBARS evolution, the application of high temperatures during cooking apparently favored the implication of hexanal in further reactions (Table 2). During the following chilled storage, however, PM and QF patties underwent intense lipid oxidation as reflected in the marked increase of hexanal (Table 2). The concordance with TBARS values, QF patties had, at the end of the processing, significantly higher hexanal levels than the patties elaborated with the other two muscles