title: Decrease of 4-vinylguaiacol during beer aging and formation of apocynol and vanillin in beer.
abstract: In this study the decrease of 4-vinylguaiacol (4VG) during beer aging was investigated and the products that arise from it were identified. Two compounds, vanillin and apocynol, were identified in beer model solutions after forced aging and in naturally aged beers by GC-MS and HPLC-ECD analyses. Both account for up to 85% of the decrease of 4VG. Only in the presence of substantial amounts of oxygen in the bottle headspace was vanillin detected. Apocynol [4-(1-hydroxyethyl)-2-methoxyphenol] was found to be the main degradation product, and its formation was shown to be highly dependent on the beer pH. Because both apocynol and vanillin have a clear vanilla-like aroma, the decrease of 4-vinylguaiacol during beer aging might impart a shift from a clove-like aroma in fresh specialty beers (such as wheat beers and other top-fermented blond or dark ales) to a sweeter, more vanilla-like flavor impression of aged specialty beers.
authors.affiliation: Centre for Malting and Brewing Science, Department of Microbial and Molecular SystemsFood and Microbial Technology, K.U. Leuven, Kasteelpark Arenberg 22, B-3001 Leuven, Belgium. nele.vanbeneden@biw.kuleuven.be
authors.forename: Nele
authors.initials: N
authors.lastname: Vanbeneden
authors.forename: Daan
authors.initials: D
authors.lastname: Saison
authors.forename: Filip
authors.initials: F
authors.lastname: Delvaux
authors.forename: Freddy R
authors.initials: FR
authors.lastname: Delvaux
mesh_terms: D001515:Beer / Q000032:analysis*; D001547:Benzaldehydes / Q000032:analysis*; D005285:Fermentation; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000032:analysis; D010636:Phenols / Q000032:analysis; D014835:Volatilization; D015003:Yeasts / Q000378:metabolism
chemical_list: D001547:Benzaldehydes; D010636:Phenols; C534597:apocynol; D006139:Guaiacol; C014245:4-vinylguaiacol; C100058:vanillin