The Organosulfur Chemistry of the Onion

Abstract

This review traces the transformation of S-alk(en)yl-L-cysteine sulfoxides, the onion aroma and flavor precursors, to a variety of remarkable cyclic and acyclic reactive organosulfur compounds, and their postulated intermediates, found in onion extracts and distillates. These compounds include sulfenic acids, mono and bis sulfines (thioaldehyde S-oxides), thioaldehydes, saturated and unsaturated thiosulfinate esters, 1,2-dithietanes 1,2-dioxides, 5,6-dithiabicyclo[2.1.1]hexanes (“zwiebelanes”), α-sulfinyldisulfides (“cepaenes”), dihydrothiophenes and thiophenes, among others.