Abstract:
The treatment in Pulsed Electric Field (PEF) represents an
application of PEF technology to feeding liquids in order to render them
sterile. The present study was initiated due to the fact that this treatment is of
utmost importance for the enological area. The objective which was followed
consisted in evaluating the inactivation effects produced by PEF treatment
applied to the germs responsible for wine damaging. Two experiments were
carried out, one of them being under specialized control, the other one
concerning the natural development of the germs in wines.
The variable factor of the controlled experiment was represented by
the type of germs (yeast strains and, respectively stems of bacteria), and in
case of the natural experiment, the level of wine stability. The studied germs
were Saccharomyces fermentati, Leuconostoc oenos (P+) 149, Leuconostoc
oenos (X+), Lactobacillus plantarum 36, Acetobacter vini VR1 and
Acetobacter vini VA1. The level of wine stability was of 5, 4 and 3 in case of
the wines taken into study.
The results obtained emphasized the fact that PEF treatment
significantly influences the viability of the germs responsible for wine
damaging, their sensitivity being however specific to the group and species of
microorganisms. The strongest bactericide effect was registered in case of
the lactic bacteria belonging to Leuconostoc oenos (P+) species to which the
diminution rate was of 3.45. Saccharomyces fermentati had the diminuation
rate value of 2.95. Leuconostoc oenos (X+) and Lactobacillus plantarum 36
revealed an average resistance to PEF treatment, their diminution rate
registering 2.47. The acetic bacteria proved to be the most resistant, maybe
because of the tiny dimensions of their cells.
The PEF treatment applied to the wines contaminated by damaging
germs significantly diminished their microbial load. The germ diminution
rate oscillated according to the nature of the contaminating agent and to the
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Universitatea de Ştiinţe Agricole şi Medicină Veterinară Iaşi
treatment length of time. Between the level of wine stability and the
diminuation rate of the microorganisms, a direct relationship of 1st grade
was registered.
The study which was carried out proved that the PEF treatment
represents a real potential for accomplishing wine sterilization.
