Lipid hydroperoxide determination in dark chicken meat through a ferrous oxidation-xylenol orange method

A ferrous oxidation-xylenol orange (FOX) method was adapted to measure lipi d hydroperoxides (LHP) in raw and cooked dark chicken meat. Its applicabili ty was evaluated using samples with different alpha-tocopherol contents or unsaturation degrees (both modulated by dietary supplementation). The FOX a ssay can work as an induced method because there is some oxidation of the s ample extract during the incubation of the reaction. Consequently, it allow s assessment of sample susceptibility to oxidation (response after some hou rs of incubation) and comparison of samples that are highly oxidized or rea dily susceptible to oxidation through their absorbance after 30 min of incu bation. It is highly specific for LHP and showed a linear relationship betw een volume of meat extract and absorbance. However, the most suitable volum e of extract and incubation time must be studied for each kind of sample. T he use of butylated hydroxytoluene during this incubation is strongly disco uraged because it attenuated the reaction by radical stabilization, thus di minishing Fe(III) formation and leading to a lower response.