GC−Olfactometric Characterization of Aroma Volatiles from the Thermal Degradation of Thiamin in Model Orange Juice

Abstract

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).

Effect of added thiamine on the key odorant compounds and aroma of cooked ham

“…These correlations reflect the structural similarities between MFT, MDTF and MFT-MFT, which are all compounds derived from reaction mechanisms directly involving thiamine. The production of MFT-MFT appeared only from a thiamine concentration of 15.9 mg kg À1 .This result is consistent with previous findings indicating that a sufficient quantity of MFT is necessary to initiate the production of a detectable quantity of MFT-MFT (Chen & Ho, 2002;Dreher et al, 2003). Although MFT and its dimer both possess a 'meaty' note, MFT-MFT is less desirable than the MFT in cooked meat because its odour gives a 'medical' note.…”

“…These compounds are difficult to analyse, because although they are easily detectable by olfaction at very low concentration, their detection by GC-MS can sometimes prove impossible (Bezman, Rouseff, & Naim, 2001), even using specific selective systems such as pulsed flame photometric detector (PFPD) (Dreher et al, 2003). Here, DHS-GC-MS proved relatively easy to implement and was able to track the desorption of MFT and its derivatives.…”

“…MFT-MFT is produced from the simple dimerization of MFT (Belitz & Grosch, 1999;Chen & Ho, 2002;Hofmann, Schieberle, & Grosch, 1996). Numerous studies in model media have successfully identified thiamine as a precursor to a broad array of sulphur compounds (Dwivedi, 1972;Cerny, 2007;Dreher, Rouseff, & Naim, 2003;Filippi et al, 2007;Thomas et al, 2014). However, all these studies have focused on the mechanisms and key parameters underpinning MFT production from thiamine, without ever addressing the quantitative aspect of this relationship.…”

Influence of the chemical structure on the odor characters of β-citronellol and its oxygenated derivatives

“…Interestingly, one single panelist described the odor of 4 as being meat-like. However, substances that have previously been associated with meaty odor, like 2-methyl-3-furanthiol and its dimer bis(2-methyl-3-furyl) disulfide, generally contain a sulfur atom in their structure (Dreher, Rouseff, & Naim, 2003;Yang, Song, Chen, & Zou, 2011). In view of this it is interesting to note that 4 was perceived as musty with a citrusy background by two panelists, so that one might speculate that the musty impression was interpreted as a meaty tone by this single panelist.…”

Analysis of grapefruit sulphur volatiles using SPME and pulsed flame photometric detection

“…However, it should be mentioned that four of the five had been also reported in prior studies. For example, Dreher, Rouseff, and Naim (2003) identified BMFDS as a thermal degradation product of thiamin in a model orange juice system. 4MMP has been described as a significant contributor to the characteristic GFJ aroma from AEDA and flavour reconstitution studies (Buettner & Schieberle, 1999.…”