Catherine Vermeulen

Sensorial Contribution and Formation Pathways of Thiols in Foods: A Review

Since the mid-1990s, more than 300 publications have been devoted to the organoleptic relevance of thiols in foods (meats, wines, fruits). The available data about their physicochemical and sensorial properties, occurrence in foods, and potential formation pathways are compiled in this article.

Combinatorial Synthesis and Screening of Novel Odorants Such as Polyfunctional Thiols

Combinatorial chemistry was shown to be an efficient tool for the preparation of new aroma-impact compounds. In this case, polyfunctional thiols were synthesized quickly using halide reagents or Bunte salt intermediates. They were separated by gas chromatography and then characterized using low resolution EI and CI mass spectrometry. The individual sensorial properties of the thiol products (i.e. odor and perception threshold) were determined by GC-O (olfactometry) which uses the human nose as detector. The thiols were characterized based on their particular odors. 3-Methyl-2-buten-1-thiol, a relevant flavor naturally present in beer and coffee, emerged as the most powerful of the thiol library.

Occurrence of polyfunctional thiols in fresh and aged lager beers

In the present work, fresh Belgian lager beers have been specifically extracted by pHMB (p-hydroxymercuribenzoic acid), according to Tominaga et al. [1]. GC-MS, GCO and GC-PFPD analyses of the extracts revealed the presence of potent odorants such as 2-mercaptoethanol (roasted, garbage), 3-mercaptopropanol (roasted, potato), 3-mercaptohexanol (rhubarb, exotic fruit), 3-mercapto-3-methylbutanol (onion, vegetable), 2-mercapto-3-methylbutanol (onion), 1-mercapto-3-pentanone (burned), 4-mercapto-4-methyl-2-pentanone (blackcurrant, box tree), 3-mercaptopropyl acetate (roasted meat), 2-mercaptoethyl acetate (toasted, roasted, burned), and 2-methyl-3-furanthiol (broth, meaty). 3-Methyl-2-buten-1-thiol, known, however, as the skunky off-flavour of samples exposed to sunlight, was also detected in fresh light-protected beers. Possible pathways for the formation of these thiols are discussed.