Natural Sulfur Compounds, Allyl Isothiocyanate and Diallyl Disulfide, Promote <i>Cis</i> to <i>Trans</i> Isomerization of Fatty Acid Esters during Heat Treatment

Abstract

IntroductionNumerous biochemical and epidemiological studies suggest that excessive intake of trans fatty acids is a significant risk factor for cardiovascular diseases. For this reason, the trans fatty acid content in food products is regulated in several countries 1,2) . Although natural unsaturated fatty acids usually exist in the cis configuration, trans fatty acids are formed through industrial hydrogenation, biohydrogenation in the rumen of cows and sheep, and upon heating during cooking 3−5) . For example, Gotoh et al. (2018) reported that heating of oleic acid and linoleic acid at 180℃ enhanced their trans isomerization within 5 min 3) . Thus, trans fatty acids cannot be completely eliminated from the human diet, but efforts should be made to reduce their content in food products.The geometric isomerization of double bonds upon heating has been well studied in carotenoids, natural tetraterpene pigments 6,7) . Recent studies have demonstrated that several sulfur compounds such as isothiocyanates and polysulfides enhance the thermal isomerization of carot-