Volatile components were isolated from Welsh onions and scallions by steam distillation at atmospheric pressure and analyzed by GC and GC-MS. Sulfur-containing compounds account for 87 % and 82 % of the total volatiles in the distilled oils of Welsh onions and scallions, respectively. In addition to the sulfur compounds commonly reported in the genus Allium, 41 novel volatile sulfur-containing components were found in the distilled oils of green onions. The novel compounds can be grouped as (1) l-[alk-(en)ylthio]alkyl alk(en)yl disulfides, (2) alkyl tetra- or pentathiaalkanes or alkene(s), and (3) thiaheterocycles. Heat may be responsible for the formation of many of the sulfur-containing volatiles in green onion distilled oils. Some of the novel polysulfides identified have sweet, scallion-like or onion-like odors.
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences(all)