# Influence of Ozone on the Biochemical Composition of Birch Sap
## 3 Results
### Physicochemical Analysis
A change in these components determines the taste of the sap. Changes in birch total soluble solids and specific conductivity during storage are shown in Figure 9A,B. After evaluation by the Dunnett test at the significance level \(p<0.05\), there were no significant differences between the control group and treatment groups in terms of both sap solids and sap specific conductivity analysis. The TSS (Total soluble solids) value of birch sap shows the percentage of dissolved substances (sucrose) in the sample (1\({}^{\circ}\) Brix corresponds to 1 g of sucrose per 100 g of solution). The Brix value of birch sap was 0.57-0.63\({}^{\circ}\) Brix. Assessing the influence of ozonation on the number of soluble solids in the sap at different temperatures (initial, 2 \({}^{\circ}\)C, and 20 \({}^{\circ}\)C) by Tukey HSD test (Figure 9A) when the significance level was \(p<0.05\) showed that ozonation had no significant effect. Figure 9B shows the change in the electric conductivity of the sap on different days: immediately after ozonation (initial); after seven days when the sap was stored at 2 \({}^{\circ}\)C; and after five days when stored at 20 \({}^{\circ}\)C. Minimal influence of ozone was seen when the product was stored for seven days after treatment (Tukey HSD test, \(p<0.05\)). Assessing the results of the sap in the following days, it was found that ozonation had no effect on the electrical conductivity of the sap immediately after ozonation or after five days of storage. To assess the correlations, a correlation analysis was performed between the acidity and the conductivity of sap (Table 1). Figure 9: Variation of total soluble solids (**A**) and electric conductivity (**B**) of birch sap during storage: 1 (control)—not ozonated sap (initial); 2—sap ozonated for 5 min; 3—sap ozonated for 10 min; 4—sap ozonated for 15 min; 5—sap ozonated for 20 min; 6—sap ozonated for 25 min; 7—sap ozonated for 30 min. Significant differences (\(p<0.05\)) were found according to a Tukey HSD test (marked in lower case) (\(n=6\)). In the correlation analysis, according to [PERSON]'s evaluation, it was observed that the relationship between pH and tittatable acidity was strong (\(r=-0.9\), correlation was significant at the 0.01 level). It can be seen that these indicators depend on each other. As the active acidity decreases, the tittatable acidity increases, i.e., the concentration of acid in the sap increases. A medium significant correlation was found between the tittatable acidity of the sap and the electrical conductivity, where the correlation value \(r\) was \(-0.576\), and between the electrical conductivity and the active acidity pH, where \(r=-0.576\) (correlation was significant at the 0.01 level). Figure 10 shows the components of fresh sap and their change after 30 min of ozonation when the ozone concentration in the sap averaged 0.99 \(\pm\) 0.09 mg L\({}^{-1}\). According to the study, ozonation did not affect the monosaccharides, sucrose content, and total sugar present in the sap. Ascorbic acid was found to decrease by about 4.5%, but the dispersion of ascorbic acid in fresh sap was higher. It is difficult to assess the changes in sugar concentrations in sap during storage. However, a deeper study with these components should be performed as needed. In summary, the data suggest that ozone at low concentrations is not harmful to sap or has a minimal effect. However, ozone is relatively effective in terms of the reduction of microorganisms.