Saponification number: Saponification number of oil is the number of milligram of potassium hydroxide required to saponify 1 g of oil. Mineral oils are the mixture of hydrocarbons and hence do not react with KOH and are not saponifiable on other hand, vegetable and animal oils are the mixtures of glycerol esters of fatty acids and require large amount of alkali to get hydrolyzed. Their Saponification values are very high.

Significance

1.      The determination of Saponification value helps us to ascertain whether the oil under reference is mineral or vegetable oil or compounded oil containing vegetable and mineral oil.

2.      Each of the oil has its own specific Saponification number. Any deviation from this value in a given sample indicates the probability and extent of adulteration.