Elementary plant Biochemistry and Biotechnology (2+1)

v. Acetyl number

Acetyl number

• It is defined as the amount in millilitres of potassium hydroxide solution required to neutralise the acetic acid obtained by saponification of 1 gm of fat or oil after acetylation
• Some fatty acids contain hydroxyl groups. In order to determine the proportion of these, they are acetylated by means of acetic anhydride
• This results in the introduction of acetyl groups in the place of free hydroxyl groups
• The acetic acid in combination with fat can be determined by titration of the liberated acetic acid from acetylated fat or oil with standard alkali
• Acetyl number is thus a measure of the number of hydroxyl groups present in fat or oil