Odor significance of undesirable degradation compounds in heated triolein and trilinolein

To better understand production of undesirable or negative odors such as fr uity, plastic, and waxy that are characteristic of higher oleic acid-contai ning oils, model heated oil systems of triolein and trilinolein were studie d. Identification of the odor significance of volatile compounds produced b y fractionated and nonfractionated triolein and trilinolein was done by pur ge and trap-gas chromatography-ion trap mass spectrometry-olfactometry. The predominant odors of the triolein heated 1, 3, and b h at 190 degreesC wer e fruity and plastic, with other negative odors of acrid and grassy. Some o f the volatile compounds that produced negative odors in heated triolein, i n order of increasing concentration, were hexanal (grassy), octanal (fruity ), (E)-2-decenal (plastic), nonanal (fruity), and (E)-2-undecenal (plastic) . Some of the negative odor compounds in trilinolein heated for 1, 3 and 6 h, in order of increasing concentration, included (E)-2-nonenal (plastic), pentanal (grassy), and hexanal (grassy). However, the amount of volatile co mpounds produced and the intensity levels of the odors were lower in trilin olein than in triolein. Formation of many of the volatiles was explained af ter identification of the volatile precursors, including epoxy, keto, and d imer oxidation products that were produced during heating.