Lecithins were extracted and purified from the dark-colored and ordinary muscles of a tuna, Thynnus orientalis.
The mixed fatty acids, prepared from these lecithins by alkali-hydrolysis, were separated into three portions, solid, lower and higher-unsaturated acids, with a combination of lead salts-ethanol and lithium salts-acetone fractionations. Individual acids were identified with paper chromatography, saturated acids and hydrogenated polyethylenic acids as their 2, 4-dinitrophenylhydrazides, and mono and diethylenic acids as their mercuric acetate complexes. Spectrophotometry of the alkali-isomerized higher-unsaturated acids indicated the presence of conjugated di-to hexaene.
The composition of these mixed fatty acids presented in Table 8 shows the component fatty acids of the lecithin from dark-colored muscle are more unsaturated than those from ordinary muscle.
The presence of cephalins, acetalphospholipids and sphingomyelin was also shown in the ethanol extracts of these tissues.