The influence of brewing yeast strains on monoterpene alcohols and esters contributing to the citrus flavour of beer was written by Haslbeck, Korbinian;Bub, Stefan;von Kamp, Kristina;Michel, Maximilian;Zarnkow, Martin;Hutzler, Mathias;Coelhan, Mehmet. And the article was included in Journal of the Institute of Brewing in 2018.Formula: C8H16O2 The following contents are mentioned in the article:
‘Aroma hops’ and especially newly bred ‘flavor hops’ are used throughout the world to impart citrus-like and/or exotic fruit-like flavors to craft beers. Citrus-like flavors in beer are known to be influenced by yeast fermentation when transforming certain secondary metabolites of the hops such as monoterpene alcs. In this study, the influence of different Saccharomyces cerevisiae/pastorianus brewing yeast strains on the citrus flavor of beers hopped at different times during beer production (30 min boiling, added during fermentation, added during maturation) with Hersbrucker, Mandarina Bavaria or Hallertauer Magnum was investigated. Yeast strains TUM 68, TUM 506, TUM 511, TUM 34/70, TUM 69 and TUM 193 that are widespread in worldwide beer production were used for standardized laboratory scale fermentations The yeast strains showed similarly low glucoside hydrolase activity in fermenting beer. The de novo synthesis of monoterpene alcs. was identified, and the geraniol decrease during fermentation was confirmed using HS-GC-MS. This research indicates that the impact of monoterpene alcs. on the citrus flavor of beer could be significantly influenced by flavor active esters owing to the combinatory effects of the flavoring substances. The results of instrumental anal. and sensory evaluation suggest that the choice of yeast strain is significant for the intensity of citrus flavor in beer. This study involved multiple reactions and reactants, such as Methyl heptanoate (cas: 106-73-0Formula: C8H16O2).
Methyl heptanoate (cas: 106-73-0) belongs to esters. Esters are also usually derived from carboxylic acids. It may also be obtained by reaction of acid anhydride or acid halides with alcohols or by the reaction of salts of carboxylic acids with alkyl halides. Acyl chlorides and acid anhydrides alcoholysis is another way to produce esters. Acyl chlorides and acid anhydrides react with alcohols to produce esters. Anydrous conditions are recommended since both acyl chlorides and acid anhydrides react with water.Formula: C8H16O2
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics