Partitioning of Exogenous δ-Tocopherol between the Triacylglycerol and Membrane Lipid Fractions of Chicken Muscle

Abstract

The partitioning of exogenous δ-tocopherol, added dissolved in ethanol, between the neutral triacylglycerols and membranes of chicken leg muscles was investigated. The two lipid fractions were separated using differential ultracentrifugation techniques. Triacylglycerols were obtained after high-speed centrifugation of the minced muscle at 130000g for 30 min. Membranes were collected from a muscle−buffer homogenate (pH 7.5) between 10000g for 20 min and 130000g for 30 min. The triacylglycerols collected represented from 15 to 80% of the total triacylglycerols of the minced muscle, the yields increasing with increasing muscle triacylglycerol content. The phospholipids in the isolated membrane fraction represented from 20 to 35% of the total phospholipids of the muscle. At low muscle total lipid contents (3−5%), the added δ-tocopherol was present in approximately the same concentration in both muscle lipid fractions. At higher total lipid contents, achieved by adding exogenous triacylglycerols, the δ-tocopherol concentration in the membranes increased relative to that in the triacylglycerols. Keywords: Tocopherol; triacylglycerols; membrane lipids; partitioning; muscle