study the effect of pectin on the acidity of the product observed in 2nd and 3rd samples. The nature of the clot is
during fermentation (diag.-1).
determined by the level of accumulation of lactic acid, 180
160
140
120
360 min
100
180 min
80
60 min
60
40
20
0
Control
1-simple
2-simple
3-simple
Diagram 1. Influence of apple pectin on the acid formation process
The results of the study the effect of added pectin Acidity also affects the viscosity of pectin solutions.
on the acidity of product shows that when adding apple
The viscosity of the pectin solution can be used to de-pectin in amount of 1-3 %, the acidity increased in 2
termine its thickening and moisture-retaining properties.
hours to 3.2% and 16.1 %, respectively and to 5.3% and
The accumulation of lactic acid during lactic acid
21.3%, respectively in 8 hours in comparison to the con-
fermentation of sugars is essential for the formation of a
trol sample.
protein clot that determines the consistency of yogurt.
The speed of the fermentation process is affected by
The resulting lactic acid reduces the negative charge of
fermentable sugars in the raw material, so the test sam-
casein micelles, since H+-ions suppress dissociation of ple 1, 2 and 3 with the addition of pectin was marked by
the carboxyl groups of casein, as well as the hydroxyl a sharp increase of acid after 2-3 hours fermentation.
groups of phosphoric acid. As a result, achieves the This is due to the breakdown of pectin which is a high
equality of positive and negative charges at the isoelec-
molecular polysaccharide to sugars, the first 2 hours, tric point of casein (pH 4.6–4.7). At the isoelectric and further fermentation by microorganisms of bacterial
point, casein or paracasein particles aggregate in a colli-
starter cultures.
sion, forming chains or threads, and then a spatial grid,
The end of fermentation is usually set to obtain a
in the cells or loops of which the dispersion medium sufficiently strong clot and titratable acidity of 75-85
with fat balls and other components of milk is captured,
°T, and a further increase in acidity can lead to a re-thus compacting the clot. Consequently, further research
charge of the protein, so that the clot structure becomes
was devoted to the influence of apple pectin on the brittle, irreversibly collapsing bonds, the yogurt loses rheological properties of yogurt.
plasticity and liquefies when stirred.