Combinatorial Synthesis and Sensorial Properties of Polyfunctional Thiols

Abstract

Over the past few years, polyfunctional thiols present as trace components have been found to play a major role in many food flavors, due to their exceptionally low odor thresholds. Unfortunately, their presence in minute concentration (in ng/kg to a few microg/kg) and their high reactivity make it very difficult to extract and identify them. Furthermore, most of them are not yet commercially available. The aim of this work was to characterize the chromatographic and sensorial properties of 10 synthetic mercaptoketones and mercaptoalcohols. Combinatorial chemistry proved to be a very useful way to synthesize them rapidly. Sulfur-selective sulfur chemiluminescence detection chromatograms coupled with mass spectroscopy enabled the target compounds to be identified. Flavor profiles and best estimate gas chromatography lowest amount detected by sniffing (BE-GC-LOADS) values were further determined by GC-olfactometry. As expected, new, exceptionally odorant molecules (BE-GC-LOADS < 0.1 ng) were revealed by this unusual approach.

Combinatorial synthesis, reversed‐phase and normal‐phase high‐performance liquid chromatography elution data and liquid chromatography/positive atmospheric pressure chemical ionization tandem mass spectra of methoxylated and glycosylated resveratrol analogues

“…Combinatorial chemistry, a method initially developed by Geysen et al .,28 has been recently applied in agrochemistry to characterize commercially unavailable flavors like thioesters and polyfunctional thiols 29–35…”

“…Combinatorial chemistry, a method initially developed by Geysen et al, 28 has been recently applied in agrochemistry to characterize commercially unavailable flavors like thioesters and polyfunctional thiols. [29][30][31][32][33][34][35] This 'one-pot' approach was used here for the first time to synthesize two libraries of stilbenes, one including 19 methoxylated stilbenes and the other, 3 glucosides. Both of them were analyzed on three HPLC columns with detection by ultraviolet (UV) and atmospheric pressure chemical ionization tandem mass spectrometry in positive mode (APCI(þ)-MS/MS).…”

Unique selective detectors for gas chromatography: Nitrogen and sulfur chemiluminescence detectors

“…Multidimensional GC coupled with SCD was also used by Koenig et al [92] for an enantiomeric distribution of 2-pentanethiol in guava fruit. Trace-level polyfunctional thiols were detected and identified by Vermeulen et al [93] using a combination of SCD and MS.…”

Fate of 2-sulphanylethyl acetate and 3-sulphanylpropyl acetate through beer aging

“…Thanks to combinatorial syntheses , four other very interesting polyfunctional thiols have recently been identified in fresh lager beers: 2‐sulphanylethan‐1‐ol (2SEol, grilled), 3‐sulphanylpropan‐1‐ol (3SProl, potato‐like), 2‐sulphanylethyl acetate (2SE‐A, burned) and 3‐sulphanylpropyl acetate (3SPr‐A, burned) . In this case, the Ehrlich pathway of cysteine or homocysteine could be involved.…”