3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
in Fig. 2. After the alcoholic fermentation the autolysis of
yeasts occurs, followed by the liberation of nutrients important
for the growth of bacteria and the growth of present
yeasts, as well.
Fig. 2. The comparison of the number of yeasts and lactic bacteria
wine factory No. 1
From the comparison of the number of yeasts in both
wine factories (Fig. 3.) follows that after the pressing the
total number of yeasts in wine factory no. 2 was lower. This
difference is probably a result of the application of small
amount of SO 2 in factory no. 2 by the start of the preliminary
fermentation of the juice. The application of SO 2 was carried
out to eliminate the development of undesirable microflora.
The difference can also result from the difference in heating
of the must in tank.
Fig. 3. The comparison of the number of yeasts in wine factories
No. 1 and No. 2
After the alcoholic fermentation the start of malolactic
fermentation is supposed. In wine factory no. 1 the amount
of bacteria of malolactic fermentation was studied (Fig. 4.).
In the case of wine factory no. 2 the commercial culture of
bacteria Oenococcus oeni was applied. The heating of the
must was realized using the heating rod. This procedure
implies that the local overheating can occur, which destroys
the microflora. In wine factory no. 2 by the application of
malolactic bacteria no bacteria of lactic fermentation were
detected.
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Fig. 4. Number of lactic bacteria – wine factory No. 1
During the study of the fermentation process the attention
was also focused on the fungi in red wine manufacturing.
From the results based on the visual evaluation of the increase
on Petri dishes can be supposed that the fungi Penicillium
and Aspergillus dominate. These can produce the different
micotoxins. Fig. 5. presents the mixed culture of microorganisms,
which grew from the grape juice in the day of crushing.
The important result is the presence of the fungi Botrytis.
Fig. 5. The mixed culture of microorganisms, which grew from
the grape juice in the day of crushing
Fig. 6. is an example of the growing blue-green colony
of yeasts with the white edge, which appeared on plates with
the grown population of the yeasts. This figure is also an
example of the fungi, which during its development colonized
the population of the yeasts
In Fig. 7. the blue-green fungi with the white edge can
be seen again. In difference to Fig. 6. this fungi during its
development did not colonize the site, where the population
of yeasts was grown. These effect is in accordance with the
observation 1 that the yeasts Metschnikowia pulcherrima,
Pichia, Candida, Cryptococcus and some Saccharomyces
and Zygosaccharomyces have strong antifungal aktivity