Other sulfur-containing furans, such as 2-methyl-3-
(methylthio)furan (9), 2-methyl-3-(methyldithio)furan
(24), and bis(2-methylfuryl) disulfide (32), were detected
with high log3 FD factors. Compound 9 was tentatively
identified as 2-methyl-3-(methylthio)furan on the basis
of published RI and mass spectral data (19). 2-Methyl-
3-(methylthio)furan was detected with a relatively high
log3 FD factor in beeflike process flavor with added
precursors, whereas this compound was not detected in
the process flavor without added precursors. 2-Methyl-
3-(methyldithio)furan and bis(2-methylfuryl) disulfide
were detected at higher log3 FD factors in the process
flavor with added precursors than in the process flavor
without added precursors. 2-Methyl-3-(methylthio)furan
and 2-methyl-3-(methyldithio)furan were proposed to be
formed via either Maillard reaction of ribose and cysteine,
involving the reaction with methanethiol, or the
reaction of 2-MF with methanethiol (16, 21). All of these
sulfur-containing furans have been previously identified
in yeast extracts (19). Bis(2-methylfuryl) disulfide is a
dimer of 2-MF, and it is known that 2-methyl-3-
furanthiol oxidizes easily to bis(2-methylfuryl) disulfide
(22).