## 3 Results and Discussion
### Influence of Storage on Content of Fatty Acids Extracted from Infant Formulas
The lowest content of monounsaturated fatty acids was also observed in the M2 mixture, approximately 19% (Figure 8). \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Fatty Acid**} & \multicolumn{3}{c}{**The Change (Beginning-6 Months of Storage) (\%)**} \\ \cline{2-4}  & **M1** & **M2** & **M3** \\ \hline C6:0 Caproic acid & 0.00 & - & - \\ \hline C8:0 Caprylic acid & \(-150.00\) & - & - \\ \hline C10:0 Capric acid & \(-110.00\) & \(-80.00\) & \(-54.55\) \\ \hline C12:0 Lauric acid & \(-100.00\) & \(0.00\) & \(0.00\) \\ \hline C14:0 Myristic acid & 0.00 & \(-36.92\) & \(-34.38\) \\ \hline C14:1 Cis-9-tetradecenoic acid & 50.00 & 40.00 & \(28.57\) \\ \hline C15:0 Pentadecanoic acid & \(-40.00\) & \(-60.00\) & \(-25.00\) \\ \hline C16:0 Palmitic acid & \(-17.51\) & \(-19.12\) & \(-17.73\) \\ \hline C16:1 Cis-9-hexadecenoic acid & 42.86 & 66.67 & 62.50 \\ \hline C18:0 Stearic acid & \(-17.32\) & \(-32.63\) & \(-35.87\) \\ \hline C18:1t Vaccenic acid & 23.08 & 0.00 & 0.00 \\ \hline C18:1 Oleic acid & 17.5 & 13.82 & 16.46 \\ \hline C18:2 Linoleic acid & 28.28 & 10.98 & 11.46 \\ \hline C18:3n-6 \(\gamma\)-Linolenic acid & 11.76 & 31.07 & 24.42 \\ \hline C18:3n-3 \(\alpha\)-Linolenic acid & 27.5 & 41.18 & 18.75 \\ \hline C20:1 Gondoic acid & 25.00 & 38.46 & 42.86 \\ \hline C22:6n-3 Docosahexaenoicenoic acid & 31.11 & 36.67 & 39.29 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Percentage differences between the contents of fatty acids in the mixtures at the beginning and after the 6-month storage period. After a six-month storage period, a decrease in the content of unsaturated fatty acids was observed for all the mixtures. At the same time, the content of saturated fatty acids increased (Figures 7-9). Lipid oxidation leads to the formation of many undesirable chemical compounds (e.g., aldehydes, ketones, esters, and free fatty acids). Unsaturated fatty acids are characterised by low oxidative stability due to the presence of multiple bonds. The oxidative stability of fatty acids depends on the number of these bonds in the molecule [42; 43]. Table 5 presents the percentage differences between the contents of fatty acids in the fresh and six-month-stored mixtures of the infant formulas. The values presented in Table 5 were calculated according to Equation (1) in Section 2.5. Lactose is an additive that protects polyunsaturated fatty acids against the harmful effects of the environment. In the M1 mixture, the main ingredient was whole milk powder. Mixtures M2 and M3 were characterised by a similar composition (Table 1). The addition of the n-6 preparation to the mixtures was very large and amounted to 34%, while the addition of the n-3 preparation was only 6.5%. Owing to the high intake of n-6 fatty acids, special attention was paid for examining their resistance to oxidation. Fatty acids from the n-6 series, mainly linoleic acid (C18:2c), are commonly present in foods containing even small amounts of fat [44; 45]. The loss of the C18:3 n-6 acid content in the M3 mixture amounted to 24.4% and was lower than the loss of that in M2 by 6.7 percentage points (Table 5). A smaller decrease in the C18:3 n-3 acid content was also observed for the M3 mixture than for the M2 mixture by 22.4 percentage points. However, the loss of C22:6 n-3 acid for the M3 mixture was 39.3%. The influences of milk proteins (casein and whey proteins) on the protection of polyunsaturated fatty acids cannot be clearly determined. Figures 10-12 present the contents of fatty acids in the studied infant formulas (agglomerates), fresh and after six months of storage. Table 6 shows the percentage differences in the contents of fatty acids in agglomerated infant formulas due to the storage time. [PERSON] et al. [44] and [PERSON] et al. [37] found that the structure and porosity of particles of bulk materials provide a greater opportunity for solvents to penetrate particles during the extraction of fat from powders. The agglomeration process changes the structure and porosity of the particles.