Butterfat

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):

Fatty acids vs triglycerides

As shown above, the composition of fats in milk is usually discussed in terms of the fatty acids. Fatty acids do not occur as such in milk (and rarely in any food). Instead, they are incorporated into compounds called triglycerides.