Therefore, maturation during aging consists of the interaction of the original compounds of the distillate, of oxidation reactions, and of the extraction of flavouring compounds from the wood.
Three characteristics determine the elimination or retention of flavouring compounds: (1) their boiling points, (2) their solubilities in ethyl alcohol and water, and (3) their specific gravities.
Recently, Styger et al. (2011a) conducted a targeted screen of genes encoding dehydrogenase, decarboxylase and reductase enzymes potentially involved in flavour compound formation via the Ehrlich pathway.
Expanding the knowledge of enzymes involved in flavour compound formation, and the genetic networks that regulate them, is crucial to advancing the capability to develop flavour-active yeasts with the best mix of flavour phenotypes.
Increased availability of genome sequences in combination with QTL studies will also reveal allelic variants of genes known to be involved in flavour compound formation, that may explain variation in 'flavour phenotypes' amongst wine yeast strains.
It is reported that fermentation temperature, aeration, and culture medium affect the lipid metabolism, which is related to cell development, membrane integrity, and the production of several byproducts, especially those directly related to flavour compounds [ 12].
Continued yeast activity also removes strong flavouring compounds such as diacetyl.
A straightforward GC MS method was developed to determine the occurrence of fourteen flavouring compounds in food.
When acted upon by an enzyme called polyphenol oxidase, polyphenols acquire a reddish colour and form the flavouring compounds of the beverage.
CYP98 activity is also needed for the biosynthesis of many phenolic flavouring compounds such as eugenol, safrole or vanilin.
