Further Determination and Characterization of the Component Acids of Butter Fat

Interest in milk fats from various sources has centered recently upon the identification of several minor component acids, chiefly unsaturated. The major components are oleic and palmitic acids, representing 50 to 55 per cent of the total mixture of fatty acids (on a molar basis). Butyric, myristic, and stearic acids, contributing 7 to 10 per cent each, account for another 25 to 30 per cent of the total acids. The remaining 20 to 25 per cent is distributed among acids occurring in amounts of 1 to 5 per cent. Of these, the saturated acids, n-hexanoic, n-octanoic, n-decanoic, and lauric, were identified by Crowther and Hynd (7); also, small amounts of saturated acids of higher molecular weight than stearic (e.g. arachidic, behenic, lignoceric, and cerotic) were reported by Helz and Bosworth (15). Hilditch and Paul (21) confirmed the presence of myristic and palmitic acids but were unable to isolate lauric acid (cf. also Caldwell and Hurtley (6)). The presence of unsaturated minor component acids of lower molecular weight than oleic was first deduced by Smedley (27). Grtin and Wirth (13) confirmed her conclusion with the isolation and identification of AgJ “-decenoic acid. The presence of C&., C14, and C16 unsaturated acids was indicated in later studies by Grtin and Winkler (12). Bosworth and Brown (3) presented further evidence for decenoic and tetradecenoic acids but were unable to detect Cl2 or Cl6 unsaturated acids. Riemenschneider and Ellis (26) found Clo, C14, and Cl6 monoethenoid acids in goat milk fat; Hilditch and Paul (21) and Longenecker (25) made similar observations when working with butter fat.