Cereal Chem 38:47 - 49.  |  VIEW ARTICLE

A Colorimetric Method for Determining Fat Acidity in Grain.

D. Baker. Copyright 1961 by the American Association of Cereal Chemists, Inc. 

A rapid colorimetric method for determining fat acidity in grain has been developed. The method is based upon the reaction of the fatty acids in benzene solution with aqueous cupric acetate to form soaps. The copper soaps are soluble in the benzene solution and the intensity of the resulting blue color of the solution is measured by a colorimeter. The intensity of the blue color measured as percent transmittance is compared with fat acidity values expressed as the number of milligrams of potassium hydroxide required to neutralize the free fatty acids in 100 grams of dry grain. For samples of wheat and corn the relationship between fat acidity values and percent transmittance is linear in the range of fat acidity values 20 to 100. The coefficient of correlation is -0.988 and -0.983, respectively, with standard deviations from regression of 2.47 and 3.42. The time required for the entire test is 10 minutes.