A method for the preparation and purification of conjugated linolenic
acids is described. The method comprises blending a mixture of vegetable
oils and or fats including various concentrations of alpha or gamma and
or both linolenic acids with a base. The method transforms approximately
over two thirds of .alpha.-linolenic acid (9Z,12Z,15Z-octadecatrienoic
acid) into 9Z,11E,15Z-octadecatrienoic acid and
9Z,13E,15Z-octadecatrienoic acid. The method also transforms
gamma-linolenic acid (6Z,9Z,12Z-octadecatrienoic acid) into
6Z,8E,15Z-octadeccatrienoic acid and 6Z,10E,12Z-octadecatrienoic acid. In
all cases, geometrical isomers and fully conjugated isomers are also
produced.