Cis-8-Octadecenoic acid, a monounsaturated fatty acid and isomer of oleic acid, trans-vaccenic acid, trans-petroselinic acid, and cis-petroselinic acid, is present in partially hydrogenated vegetable oil and milk fat.
1,2,3-Tri-6(Z)-octadecenoyl glycerol, a triacylglycerol, incorporates 6(Z)-octadecenoic acid (cis-petroselinic acid) into the sn-1, sn-2, and sn-3 positions. This compound is prevalent in plant seed oils.