Diallyl thiosulfinate was found to be a major constituent of solvent extracted garlic. Upon gas chromatography, diallyl thiosulfinate undergoes dehydration, leading to the formation of two isomeric disulfides. At room temperature diallyl thiosulfinate undergoes a rearrangement. After 24 hr, sulfur dioxide, diallyl mono-, di-, and trisulfides are the major products of this reaction. The role of thiosulfinates in the formation of flavor components of garlic and other Alliums is discussed.

The lachrymatory factor in onions was isolated by gas chromatography of a raw onion extract. By means of spectral analysis, the isolate was identified as thiopropanal S-oxide. Synthesis confirmed this identification. Thioethanal, thioacetone, thiobutanal, and thiohexanal S-oxides were also synthesized and their lachrymogenic properties were evaluated.

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The components of onion oil were examined by combined gas-liquid chromatography-mass spectrometry. The various components of the oil were also separated by preparative-scale gas chromatography and examined individually by infrared, nuclear magnetic resonance, and mass spectral techniques. 3,4-Dimethylthiophene, methyl cis-pro-penyl disulfide, methyl trans-propenyl disulfide, cispropenyl propyl disulfide, trans-propenyl propyl disulfide, two methyl propenyl trisulfides, and two propenyl propyl trisulfides not previously reported as occurring in onions were found to be important components of onion oil.

A highly purified methyl palmitate free of all detectable impurities was oxidized by aeration at 150C. Monohydroperoxide was shown by thin-layer chromatography (TLC), spot and spray test, and polarography to be the initial autoxidation product.