The profile of volatile
compounds was investigated using headspace solid-phase microextraction
coupled with gas chromatography–mass spectrometry (HS-SPME–GC–MS)
during bilberry juice fermentation with nine non-
Saccharomyces
yeasts, including
Pachysolen tannophilus
,
Metschnikowia pulcherrima
,
Hanseniaspora uvarum
,
Torulaspora
delbrueckii
,
Zygosaccharomyces bailii
,
Schizosaccharomyces pombe
,
Lachancea thermotolerans
,
Issatchenkia
orientalis
, and
Saccharomycodes ludwigii
. Dynamic changes in volatile compounds were determined simultaneously
with the development of ethanol concentration during fermentation.
H. uvarum
or
I. orientalis
produced more ethyl acetate than other yeast strains throughout
fermentation, while fermentation with
M. pulcherrima
resulted in high accumulation of higher alcohols.
S. pombe
was associated with high productions of
pentane-2,3-dione, 3-hydroxybutan-2-one, 2-methylbutanal, and 3-methylbutanal.
Among the 59 volatile compounds detected, generally, higher alcohols
and monoterpenes accumulated constantly and reached the maximum concentration
at the middle or later fermentation stage, whereas aldehydes, ketones,
and acetals accumulated first followed by a significant drop. The
production and accumulation dynamics of metabolites were highly dependent
on the yeast species and the developing ethanol content.