Influence of Fat Content and Composition on Malonaldehyde Concentration in Chicken Meat and Skin

Abstract

Total fat extracted from breast meat, leg meat, and breast skin was analyzed for composition of phospholipids (PL), triglycerides (TG), and total cholesterol (C); and for fatty acid composition of PL and TG fractions. Whole fat was also analyzed for malonaldehyde (MA) by an improved thiobarbituric acid (TBA) assay with antioxidant protection and for certain secondary oxidation products by fluorescence excitation (360 nm) and emission (440 nm) spectra. Breast contained 1.1% fat composed of 58.4% PL and 35.5% TG; leg contained 2.4% fat composed of 32.1% PL and 62.9% TG, and skin contained 32.8% fat composed of 1.6% PL and 97.8% TG. Fatty acid compositions of TG fractions from all tissues were similar and contained almost no polyunsaturated fatty acids (PUFA) with 20 or 22 carbon atoms. Fatty acids from PL fractions of meat contained more than 20% arachidonic acid and substantial amounts of PUFA with 22 carbon atoms; skin PL contained approximately one-half the PUFA with 20 and 22 carbon atoms compared with meat. The MA concentration in breast fat was 1.9 times higher than in leg fat and 20.3 times higher than in skin fat. However, because of the different fat content of tissues, the TBA number of skin was higher than that of leg, which in turn was higher than that of breast. The relative levels of fluorescent products in fat from meat and skin tissues clearly paralleled the trend found for MA concentrations. It was concluded that the TBA number parameter is of little comparative value unless accompanied by fat content and composition data.