3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures
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Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology<br />
P99 ThE IMPACT OF FERMENTATION PROCESS<br />
ON AMINO ACID PROFILE OF GRÜNER<br />
VELTLINER whITE wINE<br />
LEnKA ŠťAVíKOVá and MIROSLAV HTKA<br />
Department of Food Chemistry and Biotechnology, Faculty<br />
of Chemistry, Brno University of Technology, Purkyňova 118,<br />
612 00 Brno, Czech Republic,<br />
stavikova@fch.vutbr.cz<br />
Introduction<br />
Amino acids represent 30–40 % of total wine nitrogen.<br />
It is generally accepted, that they may act as nutrients for both<br />
yeast and malolactic bacteria during the wine fermentation.<br />
In the yeasts’ growing phase, they can be either partially or<br />
totaly metabolised, excreted by living yeasts at the end of the<br />
fermentation or released by proteolysis during the autolysis<br />
of the dead yeasts. In addition, amino acids can serve as substrate<br />
for the production of aroma compounds 3–5 or biogenic<br />
amines 6,7 in wine. On the contrary, their production by enzymatic<br />
degradation of the grape proteins was described 1,2 .<br />
There is no doubt, that their content in wines is dependent<br />
on the fertilization and climatic conditions, duration of<br />
skin maceration in the must, field treatments and on other<br />
factors 2,6–8 . Recently, amino acids’ content in wines is studied<br />
extensively for several reasons, e. g, due to the differentiation<br />
of Champagnes and sparkling wines 2 , the determination<br />
of geographic origin, variety and vintage 2,7,8 , the assessment<br />
of substances with enological interest (e.g., of aroma<br />
compounds) 3–5 , or toxicological interest (biogenic amines<br />
etc.) 6,7,9,10 , the monitoring of nitrogen metabolism during<br />
the fermentation 5,11 or their changes during the ageing of<br />
wines 12,13 .<br />
The determination of amino acid in wines is usually<br />
employed by HPLC with precolumn derivatization using<br />
o-phthaldialdehyde (OPA), fluorenylmethyl-chloroformate<br />
(FMOC) or 6-aminoquinolyl-n-hydroxysuc-cinimidyl carbamate<br />
(AQC). 2,4,6–8,10–14 Ion-exchange chromatography with<br />
post-column derivatization with ninhydrin reagent 1,9,15 or comprehensive<br />
two-dimensional gas chromatography 16 was successfully<br />
applied, as well.<br />
In this contribution, the impact of spontaneous and<br />
inoculated fermentations on amino acids profile of Grüner<br />
Veltliner (Vitis vinifera) white wine is presented, applying<br />
an ion exchange chromatography with post-column derivatization<br />
with ninhydrin and spectrophotometric detection<br />
system.<br />
Experimental<br />
W i n e S a m p l e<br />
Grüner Veltliner (Veltlínské zelené) white wine variety<br />
from Velké Pavlovice sub-region (South Moravia region,<br />
Czech Republic) was investigated. Wine samples were prepared<br />
by two different technological processes. In the first<br />
one, the spontaneous fermentation was used, whereas in the<br />
second, wine was prepared by inoculated fermentation. The<br />
s800<br />
sampling procedure was performed every other day continuously,<br />
starting from cider up to the final young wine.<br />
C h r o m a t o g r a p h i c C o n d i t i o n s<br />
Respective wine sample was analysed to free amino<br />
acids (FAA) content after its filtration and dilution in Li-citric<br />
buffer (pH 2.2), employing the AAA T339 amino acid analyser<br />
(Mikrotechna, Prague, Czech Republic) equipped with<br />
Ostion LG AnB ion-exchange resin column. Amino acids<br />
separation was achiewed by stepwise gradient elution using<br />
the Li-citric buffer system. Post-column derivatization with<br />
ninhydrin reagent and spectrophotometric measurement was<br />
used for their determination.<br />
Results<br />
Concentration profile of the following 36 compounds<br />
potentially present in wine samples under study was<br />
investigated: cysteic acid (CystAC), tautine (Tau), phosphoethanolamine<br />
(PE), urea, aspartic acid (Asp), hydroxyproline<br />
(Hpro), threonine (Thr), serine (Ser), asparagine (Asn), glutamic<br />
acid (Glu), glutamine (Gln), α-aminoadipic acid (α-<br />
AAD), proline (Pro), glycine (Gly), alanine (Ala), citrulline<br />
(Cit), α-aminobutyric acid (α-ABA), valine (Val), cysteine<br />
(Cys), methionine (Met), cystathionine (Cysne), isoleucine<br />
(Ile), leucine (Leu), tyrosine (Tyr), phenylalanine (Phe), αalanine<br />
(α-ALA), β-aminobutyric acid (β-ABA), γ-aminobutyric<br />
acid (GABA), ethanolamine (EA), ammonium (nH 3 ),<br />
ornithine (Orn), lysine (Lys), histidine (His), 1-methyl histidine<br />
(1-met His), 3-methyl histidine (3-met His), arginine<br />
(Arg).<br />
Results obtained showed, that total FAA concentration<br />
in wine samples prepared by spontaneous fermentation<br />
ranged from 302.30 mg dm –3 up to 1,578.25 mg dm –3 ,<br />
whereas in those prepared by inoculated fermentation, from<br />
289.64 mg dm –3 up to 1,371.41 mg dm –3 .<br />
In the sample prepared by a spontaneous fermentation,<br />
the total concentration of free amino acids slowly increased<br />
during the first three days from 1,299.75 g dm –3 to the maximum<br />
of 1,371.47 mg dm –3 , then in next six days of fermen-<br />
Fig. 1. Total free amino acids content monitored during 24 days<br />
in the wine samples prepared by spontaneous (�) and inoculated<br />
(�) fermentation processes