Volatile sulfur compounds have been reported to be
responsible for the sulfurous off-flavors generated during
the thermal processing of milk; however, their analysis
has been a challenge due to their high reactivity,
high volatility, and low sensory threshold. In this study,
reactive thiols were stabilized and the volatile sulfur
compounds in milk were extracted by headspace solidphase
microextraction, and analyzed by gas chromatography
and pulsed-flame photometric detection. Calibration
curves for 7 sulfur-containing compounds were constructed
in milk by the standard addition technique.
Raw, pasteurized, and UHT milk samples with various
fat contents were analyzed. Compared with raw and
pasteurized samples, UHT milk contained substantially
higher concentrations of hydrogen sulfide, methanethiol,
carbon disulfide, dimethyl trisulfide, and dimethyl
sulfoxide. The high odor activity values calculated
for methanethiol and dimethyl trisulfide
suggested that these 2 compounds, in addition to dimethyl
sulfide reported in a previous study, could be
the most important contributors to the sulfurous note
in UHT milkKeywords: volatile sulfur, milk off-flavor, solid-phase microextraction, pulsed-flame photometric detectionOriginally published in Journal of Dairy Science (http://www.journalofdairyscience.org/) and copyrighted by the American Dairy Science Association
