3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
Fig. 3. Concentration profile of individual OS in the congress
wort (A) and green beer (b) for different barley varieties. Symbols:
DP 3 (vertical lines), DP 4 (white), DP 5 (black), DP 6 (horizontal
lines), and DP 7 (transversal lines).
of eluted OS with DP < 4 corresponded exactly to the retention
times of standards of MA3, MA4 respectively, while
small shifts in the retention times for OS with DP > 4 compared
to the standards of MOS were observed. It seems that OS
with DP < 4 are mostly consisted of linear α-(1 → 4)-linked
glucose chains, while higher OS can be substituted by maltose/maltotriose
residues of α-(1 → 6)-linked chains to form
hardly fermentable saccharides so called dextrins. To identify
the actual chain position, combination of HPLC with mass
spectrometry has to be applied.
Beside the quality differences, noticeable changes
in the quantity of OS for multiple DP were observed. There
was high concentration of mono-, di-, and trisaccharides
s609
in the congress wort and hopped worth, while green beer
and beer revealed significant decrease of these saccharides
as expected after fermentation process. Especially maltose
– the most abundant saccharide in the congress wort – was
mostly fermented, so its concentration significantly decreased
in the green beer (Fig. 1.A). In comparison, the concentration
of OS with DP > 4 did not show any significant
changes neither in the wort nor in the beer samples. Their
concentration remained on the same levels in all wort samples
(Fig. 1.B).
Beside concentration changes in the wort samples of the
same variety, significant changes in the content of low-weight
saccharides (up to DP 4) in the congress wort of different barley
varieties were found (Fig. 2.).
Obtained calibration data were used for quantification
of OS corresponded to those with DP 3 to DP 7. The content
of individual OS from different barley varieties is shown in
Fig. 3.
The highest concentration of MA3 and MA4 was found
in the Bojos variety, while Maltasia revealed the lowest concentration.
Observed changes in the saccharide concentration
can serve as the indicator of the quality and the usefulness of
individual barley varieties; therefore, is essential in the development
and production of new sort of beer.
Conclusions
ACn/water 3 : 2 (v/v) with flow rate of 1 ml min –1 provided
for good separation of oligosaccharides up to tetradecasaccharides
in 45 minutes duration. Significant changes
in the quantity of low oligosaccharides in eleven different
wort samples were found. The changes in the concentration
and pattern of OS are important knowledge for development
of the new brewing technologies.
Work was supported by the Ministry of Education, Youth
and Sports of theCzech Republic, project No. 2B06037 and
Institutional Research Plan AV0Z40310501.
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