| Abstract
| - Model orange juice solutions containing 0.024 mM thiamin hydrochloride were stored for up to 8weeks at 35 °C in amber glass containers. Volatiles were evaluated, primarily, using gas chromatography (GC) with olfactometry but also with flame ionization detector , pulsed-flame photometerdetector (PFPD) (sulfur specific), and MS detection. Both 2-methyl-3-furanthiol (MFT) and its dimer,bis(2−methyl−3−furyl) disulfide (MFT−MFT) were identified thus confirming that thiamin could serveas the precursor to these potent off-flavors in thermally degraded citrus juices. Thirteen aroma activecomponents were observed. MFT and MFT−MFT were observed after only a few days storage, andproduced 33% of the total aroma activity after 7 d storage. Both compounds were observedolfactometrically earlier than they could be detected using PFPD. Other aroma-active compoundsincluded 4,5-dimethylthiazole (skunky, earthy), 3-thiophenethiol (meaty, cooked), 2-methyl-4,5-dihydro-3(2H)-thiophenone (sour-fruity, musty, green), 2-acethylthiophene (burnt), 2-formyl-5-methylthiophene(meaty), and 2-methyl-3-(methyldithio) furan (meaty). Keywords: Thiamin; 2-methyl-3-furanthiol; bis(2−methyl−3−furyl) disulfide; aroma; gas chromatography-olfactometry; GC−O; Pulsed Flame Photometric Detection; PFPD.
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