Lactones in butter,butteroil, and margarine

The γ- and Δ-lactones of butter, butteroil, and margarine samples were determined by a recently developed extraction and chromatographic method. A chromatographic column is made of three layers consisting of 6 g aluminum oxide upon which is placed 35 g sodium sulfate and then a fat-Celite mixture obtained by grinding 10 g sample with 35 g Celite 545. The column was eluted with acetonitrile, and the extract was concentrated and lactones determined by gas chromatography. γ-Dodecalactone, Δ-decalactone, Δ-dodecalactone, and Δ-tetradecalactone were recovered quantitatively. Freshly made butter had only 7 ppm of these lactones, whereas commercial samples ranged from 12–30 ppm. Two of eight commercial margarine samples had as much as 10 ppm of Δ-decalactone and Δ-dodecalactone. Comparison of unheated butteroil with butteroil heated at various temperatures showed a correlation of lactone content with time and temperature of heating. Butteroil heated at 65 or 100 C showed increasing levels of lactones up to 8 hr, whereas butteroil heated at 145 or 125 C showed a maximum production at ca. 2 and 4 hr, respectively.