A free fatty acid (FFA) is a
fatty acid that is not chemically attached (esterified) to
glycerol or another molecule.
For example, in a
triglyceride, three fatty acids are esterified to glycerol:
- Triglyceride → glycerol + 3 fatty acids
When one of those fatty acids is released from the triglyceride, it becomes a free fatty acid.
In digestion, when you eat
fat,
lipases break the ester bonds in triglycerides, releasing fatty acids and
monoglycerides. The released fatty acids are therefore referred to as free fatty acids.
They can be:
So, “free” refers to its chemical state, not its chain length or saturation.