GC-olfactometric characterization of aroma volatiles from the thermal degradation of thiamin in model orange juice.
Model orange juice solutions containing 0.024 mM thiamin hydrochloride were stored for up to 8 weeks at 35 degrees C in amber glass containers. Volatiles were evaluated, primarily, using gas chromatography (GC) with olfactometry but also with flame ionization detector, pulsed-flame photometer detector (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 serve as the precursor to these potent off-flavors in thermally degraded citrus juices. Thirteen aroma active components were observed. MFT and MFT-MFT were observed after only a few days storage, and produced 33% of the total aroma activity after 7 d storage. Both compounds were observed olfactometrically earlier than they could be detected using PFPD. Other aroma-active compounds included 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).
Institute of Food and Agricultural Sciences, Citrus Research and Education Center, University of Florida, 700 Experiment Station Road, Lake Alfred, FL 33850, USA.
J Glen
JG
Dreher
Russell L
RL
Rouseff
Michael
M
Naim
D000328:Adult; D001628:Beverages / Q000032:analysis*; D002849:Chromatography, Gas; D002957:Citrus / Q000737:chemistry*; D019281:Dimerization; D005260:Female; D005663:Furans / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006358:Hot Temperature; D006801:Humans; D008297:Male; D009812:Odorants / Q000032:analysis*; D012903:Smell; D013438:Sulfhydryl Compounds / Q000032:analysis; D013831:Thiamine / Q000737:chemistry*; D014835:Volatilization
D005663:Furans; D013438:Sulfhydryl Compounds; C443400:2-methyl-3-furanthiol; D013831:Thiamine