Saponification Value
Fats and oils are the stored forms of energy in many organisms. They are highly reduced compounds and are derivatives of fatty acids. Fatty acids are made up of carboxylic acids with hydrocarbon chains of 4 to 36 carbons. Fatty acids can either be saturated (solid in room temperature) or unsaturated (liquid in room temperature). The simplest lipids made from fatty acids are triacylglycerols or triglycerides. Triacylglycerols are fatty acid that is composed of three fatty acids each in ester linkage with a glycerol.

The term “Saponification” literally means "soap making". It is the hydrolysis of fats or oils under basic conditions to get the glycerol and the salt of the corresponding fatty acid.
Saponification is important to the industrial user for it helps to know the amount of free fatty acid that is present in a food material. The quantity of free fatty acid can be distinguished by determining the quantity of alkali that must be added to the fat or oil to make it neutral. This test is done by warming a known amount of oil or fat with alcoholic KOH, which will convert the free fatty acid into soap. This soap is removed and the amount of fat remaining is then determined by subtracting the amount of obtained soap from the amount of fat originally taken before the test.
The saponification number or “sap” measures the present bonded or unbonded acids in oil or fats. This number defines the exact number of milligrams of potassium hydroxide