The oxidation of the lipid fraction and cholesterol in raw and cooked chicken breast samples stored for 0 and 6 days at 4°C under aerobic conditions and in vacuum packaging was studied. The multivariate statistical analysis showed significant effects of both culinary process and storage conditions on the lipid and cholesterol oxidation process, with a significant interaction between the two variables. Aerobic storage increased thiobarbituric acid reactive substances (TBA) from 0.04 to 0.06 ppm for raw samples, from 0.21 to 1.20 ppm for grilled samples, and from 0.24 to 1.62 ppm for roasted samples. During vacuum storage, only roasted samples showed significant increases in TBA. Levels of total cholesterol oxidation products (COP) remained low (2.88 to 4.35 μg/g of lipid) for all raw samples. Cooking increased COP levels to 12.85 and 11.54 μg/g of lipid for grilled and roasted samples, respectively. Total COP and all individual COP except for cholestanetriol were significantly correlated with TBA and the peroxide index. However, the most extensive effect was attributable to the aerobic storage of cooked samples, which led to COP levels of 92.35 and 88.60 μg/g of lipid in grilled and roasted samples, respectively. Vacuum packaging did not increase COP levels for cooked samples.
Effects of Processing Stage and Storage Conditions on Cholesterol Oxidation Products in Butter and Cheddar Cheese
