Estimation of fat acidity in milled wheat products. Part I. Colorimetric determination

Abstract

Fat acidity of milled wheat products was determined by copper soap colorimetry. The procedure involved dissolving chlorofonn-extracted oil in iso -octane (2,2,4-trimethyl-pentane) and measuring the colour developed by the interaction of fatty acids with a cupric acetate-pyridine reagent. The method was accurate and reproducible. Equivalent results were obtained with oleic, linoleic and palmitic acids, the three major component fatty acids of wheat oil. Results were compared with the American Association of Cereal Chemists (AACC) official titration method. The colorimetric procedure provides decided advantages over the AACC method; these include objectivity of measurement, more rapid analysis, ease of assay at high levels of fatty acids and a more accurate detennination of acidity due to fatty acids. Results were also not affected by emulsion-fonning polar lipids, which can occur when using the AACC titration method.