Question

Difference between acid value and saponification value

Answer 1

Acid value refers to the amount of "free" fatty acids in the oil/fat. 
Saponification value refers to the amount of esters that can be hydrolysed and turned into soap. 
Both these values are given as mg KOH per g of oil or fat

Answer 2

Explanation:

Acid value is defined as the amount of KOH needed in milligrams to neutralize the organic acid which is present in 1 gram of fat. It is used to measure the free fatty acid (FFA) that are present in the fat or oil.

Saponification value is defined as the amount of KOH (potassium hydroxide) required in milligrams to to turn 1 gram of fat into soap. It depends on the nature of the fatty acids that are contained in the fat.