Chromatographic Separation of Some Milk Lipids

Abstract

Fats extracted from milk and from dried buttermilk by mixtures of ethyl ether and pentane were chromatographed on silicic acid columns. Butanol was used to split the lipoprotein complexes in the buttermilk. Each fat in pentane was applied to the column and eluted with successive portions of 1, 10, 25, and 50% ethyl ether in pentane, with methanol, with acetone, and with water. Cholesterol and phospholipids were separated but most of the tocopherols and carotenoids remained with the triglycerides. Unsaponifiable matter prepared from churned fat was applied in hexane to alumina and celite (2:1) and to magnesia and celite (1:1) columns. The material on the alumina-celite column was eluted successively with hexane, benzene, ethyl ether, and methanol. A fraction characterized as 70% cholesterol by chemical analysis and infrared spectrophotometry was recovered from the benzene eluate. The magnesia-celite column yielded 95% cholesterol in the benzene eluate. Carotenoids were separated by developing the column with hexane to obtain 5 clearly defined zones. These were rechromatographed to obtain homogeneity. Characteristic absorption curves and partition tests established the presence of beta-carotene, neo-betacarotene, lutein (xanthophyll) and zeaxanthin in the eluted fractions.