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.