## 3 Results and Discussion
### Profile of Fatty Acids
Currently, the most frequently used for the evaluation of different food FA nutritional indices are [24]: PUFA/SFA--ratio of total PUFA to total SFA; IA--index of atherogenicity; HPI--health-promoting index (which is the reciprocal of IA and mainly used in research on dairy products); IT--index of thrombogenicity; HH--hypochlesterolemic/hypercholesterol ratio; UI--unsaturation index. The calculation of mentioned indices for the studied dairy beverages is presented in Table 4. Generally, all of the calculated indices were in the range previously reported for different yogurts [24]. Interestingly, all FA indices of kefir calculated in this study were significantly better (i.e., higher PUFA/SFA, HPI, HH and UI; lower IA and IT) than those previously reported for milk fermented with different kefir grains [37]. This can be possibly explained by different kefir preparation processes: while in Russia commercial kefir is prepared using intermediate starter (\"mother culture\") [4], many scientific articles utilize \"traditional\" fermentation by kefir grains themselves [38]. The comparison of studied dairy beverages in terms of the mentioned FA nutritional indices \begin{table}
\begin{tabular}{c c c c c c c c} \hline \multicolumn{2}{c}{**Fatty Acid**} & \multicolumn{6}{c}{**Relative Abundance, \%**} \\ \hline \multirow{2}{*}{**Name**} & \multirow{2}{*}{**Abbreviation**} & \multicolumn{2}{c}{**Kefir**} & \multicolumn{2}{c}{**Ryazhenka**} & \multicolumn{2}{c}{**Amaasi**} \\ \cline{3-8}  & & **Mean** & **SD** & **Mean** & **SD** & **Mean** & **SD** \\ \hline \multicolumn{8}{c}{Polyunsaturated fatty acids (PUFA)} \\
9,12-Octadecadienoic acid & C182 (\(n-6\)) & 4.04  & 0.140 & 3.50  & 0.250 & 2.04  & 0.134 \\
10,12-Octadecadienoic Octadecadienoic acid & C182 (\(n-6\)) & 1.06  & 0.014 & 1.29  & 0.008 & ND & - \\
8,11,14-Eicosatrienoic acid & C203 (\(n-6\)) & 0.23 & 0.023 & ND & - & ND & - \\
5,8,11,14-Eicosatrienoic & C204 (\(n-6\)) & 0.19 & 0.025 & 0.16 & 0.016 & ND & - \\
5,8 & & & & & & & \\ Eicosatetraenoic acid & C204 (\(n-6\)) & 0.19 & 0.025 & 0.16 & 0.016 & ND & - \\
5,8 & & & & & & & \\ Total PUFA & & 5.53  & 0.145 & 4.96  & 0.251 & 2.04  & 0.134 \\  & & & & & & & \\  & & & & & & & \\ Tridecanoic acid, & iso-C14:0 & 0.26  & 0.021 & 0.33  & 0.024 & ND & - \\
12-methyl & anteiso-C15:0 & 0.45  & 0.010 & 0.53  & 0.016 & 0.59  & 0.023 \\
14-methylhexadecanoic & anteiso-C17:0 & ND & - & ND & - & 0.57 & 0.071 \\
15- & & & & & & & \\ methylhexadecanoic & iso-C17:0 & 0.45  & 0.010 & 0.34  & 0.016 & 0.62  & 0.052 \\  & acid & & & & & & \\ Total BCFA & & 1.17  & 0.025 & 1.19  & 0.033 & 1.79  & 0.091 \\ Hexanoic acid, & & & 2-hydroxy fatty acids (2 OH-FA) & & & & \\
2-hydroxy & & & & & & & \\ Butyric acid, & & & & & & \\
2-hydroxy-3-methyl & & & & & & & \\ Pentanoic acid, & & & & & & \\
2-hydroxy-3-methyl & & & & & & \\ Total 2 OH-FA & 0.17  & 0.009 & 0.05  & 0.002 & ND & - \\ \hline \end{tabular} ND: not detected; SD: standard deviation.  
\end{table} 
Table 3: _Cont._clearly showed that these indices for kefir and ryzzhenka were similar and significantly better than for amasi. While previously mentioned indices are calculated using only SFA, MUFA and PUFA in one way or another, they totally missed two important classes of FA--BCFA and 2 OH-FA. While the dietary implication of 2 OH-FA is still largely unknown [39; 40], BCFA have recently been proposed as bioactive molecules with pro-health benefits [41]. Moreover, the human body can derive only a limited amount of BCFAs from dietary branched chain amino acids, and dietary fats remain the most important source of BCFA within the body [42]. The determined contents of BCFA for kefir and ryzzhenka were similar (1.17-1.19%) but, in contrast to the FA nutritional indices, they were significantly worse (i.e., lower) than for amasi (1.8%).