This study examined the relationship between protein and lipid oxidation and the impairment of water holding capacity (WHC), colour and texture after frozen storage (20 weeks/−18 °C) and subsequent processing (cooking, chilled storage) of beef patties with increasing fat content (3, 20 and 35%). Various manifestations of protein oxidation were found to occur during frozen storage and processing of patties including, loss of tryptophan fluorescence, carbonylation and formation of Schiff bases structures (SB). Patties with higher fat content underwent the more intense protein oxidation as assessed by formation of protein carbonyls and SB, highlighting the timely interaction between proteins and oxidizing lipids. Protein oxidation occurred concomitantly with loss of WHC and discolouration of beef patties. Mechanisms and consequences of the chemical modifications induced by oxidative stress in meat proteins are thoroughly discussed.