Fat indices

FAT INDICES

  • The following are the fat indices
    • Acid number
      • It is the number of milligrams of KOH required to neutralize the free fatty acids present in 1 g of fat.
      • The acid number thus tells us of the quantity of free fatty acid present in fat. Fat, which has been processed and stored properly, has a very low acid number.
      • It is the number of milligrams of KOH required to saponify 1 g of fat or oils.
      • The saponification number thus provides information on the average chain length of the fatty acids in the fat. It varies inversely with the chain length of the fatty acids. The shorter the average chain length of the fatty acids, the higher is the saponification number.
      • It is the number of grams of iodine absorbed by 100 g of fat.
      • The iodine number is a measure of the degree of unsaturation of the fatty acids in the fat.
      • Oils like soybean, cotton seed oil have higher iodine number than the solid fats such as beef fat because, the former contain more unsaturated fatty acids in the fat molecule.
      • However, iodine value gives no indication of the number of double bonds present in the fatty acid molecule.
      • It is the number of milligrams of KOH required to neutralize the acetic acid obtained by saponification of 1 g fat after it has been acetylated.
      • This is a measure of the number of hydroxy- acid groups in the fat.
      • Castor oil, because of its high content of ricinoleic acid, a fatty acid containing one OH group, has a high acetyl number (about 146).
      • It is the number of milliliters of 0.1 N KOH required to neutralize the insoluble fatty acids (those not volatile with steam distillation) from 5g of fat.
      • It is a measure of non-volatile (long chain) fatty acids present in a fat.
      • It is the number of milliliters of 0.1 N KOH required to neutralize the soluble volatile fatty acids derived from 5 g of fat.
      • R.M. number thus measures the quantity of short chain fatty acids in the fat molecule.
Last modified: Tuesday, 22 March 2011, 11:10 AM