Butterfat or milkfat is the fatty portion of milk. Milk and cream are often sold according to the amount of butterfat they contain. Composition The fatty acids of butterfat are typically composed as follows (by mass fraction): Saturated fatty acids: Palmitic acid: 31% Myristic acid: 12% Stearic acid: 11% Lower (at most 12 carbon atoms) saturated fatty acids: 11% Unsaturated fatty acids: Oleic acid: 24% Palmitoleic acid: 4% Linoleic acid: 3% Linolenic acid: 1% U.S. Standards In the U.S.… (More on Butterfat)