Measurement of 2-thiobarbituric acid values in dark chicken meat through derivative spectrophotometry: influence of various parameters.

Several variables (kind of filter paper, amount of sample, antioxidant addition, stability of the spectrophotometric measurement, and handling and storage of samples) were found to influence 2-thiobarbituric acid (TBA) values in dark chicken meat when an acid aqueous extraction method with derivative spectrophotometry was used. Filter papers with larger pore diameter or increasing sample weight led to lower TBA values. After incubation of reaction mixtures at 70 degrees C and ice-cooling, tempering for 45 min at room temperature was necessary to stabilize the spectrophotometric measurement. Furthermore, addition of butylated hydroxytoluene (BHT) and ethylenediaminetetraacetic acid disodium salt (EDTA) in the early steps of the method prevented artifactual formation of TBA reactive substances during analysis. Vacuum packaging and storage of samples at -20 degrees C were useful to avoid sample oxidation. The method finally proposed has a coefficient of variation of 3.81 or 4.13% for raw or cooked samples, respectively.