Thioctic Acid in Milk

Abstract Thioctic acid ( α -lipoic acid) was isolated from milk and found to be associated with the fat globule membrane. The isolation procedure was as follows: Sweet cream buttermilk was hydrolyzed by refluxing for 3 hr with 6.0 n HCl. A benzene extract of the hydrolysate was extracted with 5% NaHCO 3 which, in turn, was acidified to pH less than 1 with 6.0 n HCl. The acidified solution was extracted with ethyl ether, and the extract evaporated to dryness and stored under nitrogen −10C. Identification of thioctic acid was accomplished by UV absorption spectra, thin-layer and gasliquid chromatography techniques.