Calculations of titrated acidity, carried out applying the received kinetics
equation, showed good approximation to the experimental values (Table 4). The
fractional accuracy's value is within the range of 0.24 ... 9.45%, which is quite
acceptable for mathematical description of biochemical processes.
The geometric interpretation of the dependence of titrated acidity of fermented
birch sap on sugar concentration and fermentation process's duration, obtained by the
equation (2), is given at Figure 7.
Figure 7. Dependence of titrated acidity of fermented birch sap on sugar
concentration and fermentation process's duration
From the Figure given above, it is clear that the dependence of titrated acidity of
fermented birch sap on fermentation process's duration has S-shaped pattern, peculiar
for the majority of fermentation processes. The process speed is very low at the
beginning of fermentation, in the middle stage the speed is rapidly increasing, and it
essentially decelerates at the end of fermentation. It is also seen that with the increase
in the initial concentration of sugars c
0
, the process of fermentation runs faster and
titrated acidity significantly increases during the same process duration.
Dependence of titrated acidity of fermented birch sap on initial concentration of
sugars c
0
(irrespective of fermentation duration) has linear direct proportional nature.
However, it can be noted that lactic acid's accumulation rate in the process of
fermentation, depending on initial concentration of sugars c
0
, varies at different stages
of the process: it is very low at the beginning of fermentation, higher in the middle
stage and reaches its highest values at the end of fermentation.
Fermentation process's duration of 4 days can be recommended as a rational one
taking into account the described type of lactic acid accumulation pattern.
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