LIPID STABILITY OF BEEF MODEL SYSTEMS WITH HEATING AND IRON FRACTIONS

Catalytic effects of different temperatures (55, 70, 85, and 100 degre es C) on lipid oxidation were studied in aqueous- and chloroform/metha nol-extracted beef model lipid systems containing iron forms inherent in beef (water-extractable, diffusate, nondiffusate, ferritin, myoglob in, hemoglobin), hematin, FeCl2, or FeCl3. Heating increased thiobarbi turic acid and peroxide values in both systems. All forms of iron cata lyzed lipid oxidation in aqueous systems, with greatest oxidation by h eme and low molecular weight iron fractions. Oxidation in lipid extrac ts was not increased by ferritin, FeCl2, or FeCl3, but heme iron was t he major oxidation catalyst. Lipid stability decreased with addition o f any iron forms inherent in beef or with increased heating, which hel ps understanding of rapid oxidation of meat during refrigerated storag e or after cooking.