Decarboxylation of substituted cinnamic acids by lactic acid bacteria isolated during malt whisky fermentation
I found this:
Seven strains of Lactobacillus isolated from malt whisky fermentations and representing Lactobacillus brevis, L. crispatus, L. fermentum, L.
hilgardii, L. paracasei, L. pentosus, and L. plantarum contained genes for hydroxycinnamic acid (p-coumaric acid) decarboxylase. With the exception of
L. hilgardii, these bacteria decarboxylated p-coumaric acid and/or ferulic acid, with the production of 4-vinylphenol and/or 4-vinylguaiacol,
respectively, although the relative activities on the two substrates varied between strains. The addition ofp-coumaric acid or ferulic acid to
cultures of L. pentosus in MRS broth induced hydroxycinnamic acid decarboxylase mRNA within 5 min, and the gene was also induced by the indigenous
components of malt wort. In a simulated distillery fermentation, a mixed culture of L. crispatus and L. pentosus in the presence of Saccharomyces
cerevisiae decarboxylated added p-coumaric acid more rapidly than the yeast alone but had little activity on added ferulic acid. Moreover, we were
able to demonstrate the induction of hydroxycinnamic acid decarboxylase mRNA under these conditions. However, in fermentations with no additional
hydroxycinnamic acid, the bacteria lowered the final concentration of 4-vinylphenol in the fermented wort compared to the level seen in a pure-yeast
fermentation. It seems likely that the combined activities of bacteria and yeast decarboxylate p-coumaric acid and then reduce 4-vinylphenol to
4-ethylphenol more effectively than either microorganism alone in pure cultures. Although we have shown that lactobacilli participate in the
metabolism of phenolic compounds during malt whisky fermentations, the net result is a reduction in the concentrations of 4-vinylphenol and
4-vinylguaiacol prior to distillation.
VAN BEEK Sylvie ; PRIEST Fergus G.
edit
And this :http://www.socgenmicrobiol.org.uk/pubs/micro_today/pdf/020408.pdf
Obviously that Laprhoaigh flavor could not derive from the cask
[Edited on 21-2-2007 by albabatter]
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