ONION (ALLIUM-CEPA L.) THIOSULFINATES RESPOND TO INCREASING SULFUR FERTILITY

Onions (Allium cepa L.) were greenhouse grown with various sulfur fert ilities and assayed for changes in thiosulfinates and related compound s. The concentrations of methyl, n-propyl, and 1-propenyl thiosulfinat es, the zwiebelanes, and the onion lachrymatory factor (LF) increased with a linear trend as sulfur fertility increased with the exception o f methanesulfinothioic acid S-n-propyl ester (MeS(O)SPr-n) and methane sulfinothioic acid S-methyl ester (MeS(O)SMe). The (thiosulfinate plus zwiebelanes):LF ratio increased with increased sulfur fertility, sugg esting that the former were being formed at a greater rate at higher s ulfur fertility. Variation in absolute and relative concentrations of these three classes of sulfur compounds with changing S fertility coul d cause subtle flavor differences in onion.