Acid value

Acid value (also known as acid number or acid index) is a common parameter in the specification of fats and oils. It is defined as the weight of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance. The acid value is a measure of the amount of carboxylic acid groups in a chemical compound, most often a fatty acid.

Overview

The acid value is used in the food industry to indicate the quality of fats and oils. A high acid value generally indicates a high degree of hydrolysis, which can be a sign of spoilage in food products. In the chemical industry, the acid value is used to determine the amount of unreacted acids in a finished product, which can be important for quality control.

Determination

The acid value is determined by titration with a standard solution of potassium hydroxide. The end point of the titration is usually determined by a color change in a pH indicator. The acid value is then calculated from the volume of KOH solution used in the titration.

Applications

In addition to its use in the food and chemical industries, the acid value is also used in the pharmaceutical industry to determine the quality of pharmaceuticals that contain fats or oils. It is also used in the cosmetics industry to determine the quality of cosmetic products that contain fats or oils.

See also

• Saponification value
• Iodine value
• Hydroxyl value