## 3 Results and Discussion
### Antioxidant Activity of Milk and Yogurts  
Table 2 presents the antioxidant potential of the bulk milk and yogurts determined with three methods, i.e., FRAP, DPPH, and ABTS. Regardless of the experimental group and the method used, the yogurts had higher antioxidant activity than the bulk milk. Noteworthy, compared to the CM samples, the DPPH scavenging activity of the control yogurts (CY) was twofold higher (an increase from 1.14 to 2.52 mg Trolox/100 mL) (\(p\leq 0.01\)). The activity assessed in the FRAP and ABTS assays increased by approximately 60-70%. Similar differences were found in the experimental group, i.e., the experimental yogurts (EY) had significantly (\(p\leq 0.01\)) higher antioxidant potential values than the milk (EM) in this group. Many studies [39; 40; 41] have found that lactic fermentation has a positive effect on the antioxidant activity of manufactured products. Peptides and free amino acids released during milk fermentation increase the antioxidant capacity of products and inhibit lipid peroxidation [39]. Additionally, the use of herbal mixtures in nutrition has been shown to improve the antioxidant potential of milk and yogurts. Our previous study [20] showed that the addition of a herbal mixture to the feed ration for cows contributed to a significant increase in the content of bioactive components with antioxidant properties in  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Control Group** & **Experimental Group** \\ \hline Active acidity (pH) & 6.72 \(\pm\) 0.04 & 6.73 \(\pm\) 0.05 \\ Potential acidity (\({}^{\circ}\)SH) & 6.86 \(\pm\) 0.10 & 6.82 \(\pm\) 0.08 \\ Dry matter (\%) & 13.09 \(\pm\) 0.20 & 13.19 \(\pm\) 0.44 \\ Total protein (\%) & 3.47 \(\pm\) 0.52 & 3.51 \(\pm\) 0.62 \\ Casein (\%) & 2.80 \(\pm\) 0.41 & 2.85 \(\pm\) 0.54 \\ Fat (\%) & 4.27 \(\pm\) 0.89 & 4.30 \(\pm\) 0.87 \\ Lactose (\%) & 4.65 \(\pm\) 0.17 & 4.72 \(\pm\) 0.13 \\ SCC (thous./mL) & 204 \(\pm\) 48 & 183 \(\pm\) 62 \\ TMC (thous. CFU/mL) & 7.2 \(\times\) 10\({}^{4}\) & 5.5 \(\times\) 10\({}^{4}\) \\ \hline \hline \end{tabular}
\end{table}
Table 1: Acidity, basic chemical composition, and hygienic status of bulk milk used for the production of yogurts.  
milk, i.e., whey proteins and lipophilic vitamins. The antioxidant capacity of milk increased as well. Similarly, other authors [12; 23; 42; 43] reported that the use of herbal blends in cow nutrition improved the nutritional value of milk via an increase in the content of bioactive components (unsaturated fatty acids, whey proteins, vitamins) in milk and dairy products and, consequently, an increase in their antioxidant potential. Irrespective of the determination methods employed, the yogurts from the experimental group (EY) had approximately 30% higher antioxidant potential values (\(p\leq 0.01\)) than the control product (CY). The higher antioxidant activity of the EY samples than that of CY was probably associated with the addition of natural antioxidants, i.e., phenolic compounds present in the herbal blends. Plant extracts may contribute to an increase in the level of endogenous antioxidants and reduction of free radicals [44].