Definition:
The Reichert-Meissl (RM) value is the number of milliliters of 0.1 N potassium hydroxide (KOH) required to neutralize the volatile water-soluble fatty acids distilled from 5 grams of fat or oil.
Significance:
Indicates the amount of short-chain fatty acids (especially butyric, caproic acids) in the fat, which are typical in butterfat and certain dairy fats.
Used to differentiate between different types of fats, especially butter from margarine or other fats.
Principle:
The fat or oil is saponified, and the volatile fatty acids are distilled and collected in a known amount of standard KOH solution.
The excess KOH is then titrated with a standard acid solution, and the RM value is calculated based on the titration results.
Equation of Reichert-Meissl:
