Precursors of methyl ketones in butter

Butterfat, when treated with Girard-T reagent, yields a series of six pyrazolones, corresponding to six even-numbered β-ketoacids (C6 up to and including C16). This is in agreement with the formation of six odd-numbered methyl ketones (C5 up to and including C15) on subjecting butterfat to steam-deodorization. The presence in butterfat of nonvolatile β-ketoacid esters has been proved. If they are glycerides, their amount is estimated at 0.03%.