# Study of the Properties of Human Milk Fat Substitutes Using DSC and GC Methods
## 4 Discussion  
HMF provides approximately 50% of infants' total energy intake and consists mainly C18:1, C16:0, and C18:2 FAs [34]. The long-chain polyunsaturated FAs (LCPUFA) are also present in HMF at levels tied to the mother's eating habits. The main LCPUFAs in HMF are arachidonic acid (ARA), docosahexaenoicoic acid (DHA), and eicosapentaenoic acid (EPA). DHA and ARA are membrane FAs necessary for development and growing of the infants' central nervous system. FAs such as DHA and ARA also influence bone mineralization, bone mass growth, and the synthesis of eicosanoids, i.e., tissue hormones. Therefore, the human milk fat substitutes should also contain these LCPUFAs in appropriate amounts [35]. In comparison with HMF, lard is a source of palmitic and oleic acids at a similar level, but it is characterized by less content of linoleic and higher amounts of \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Heating Rates (\({}^{\circ}\)C/min)**} & \multicolumn{3}{c}{**T\({}_{\text{on}}\) (\({}^{\circ}\)C)**} \\ \cline{2-4}  & **LR70\_4** & **LR70\_8** & **LR70\_24** \\ \hline
2.5 & 140.2 \(\pm\) 1.6 & 150.9 \(\pm\) 0.1 & 149.7 \(\pm\) 1.3 \\
5.0 & 147.8 \(\pm\) 0.6 & 156.4 \(\pm\) 1.9 & 161 \(\pm\) 1 \\
7.5 & 153.0 \(\pm\) 0.4 & 166.6 \(\pm\) 1.7 & 168.2 \(\pm\) 0.6 \\
10.0 & 162.0 \(\pm\) 0.2 & 171.3 \(\pm\) 0.9 & 172.7 \(\pm\) 0.4 \\
12.5 & 164.4 \(\pm\) 1.3 & 174.9 \(\pm\) 1.0 & 176.4 \(\pm\) 0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Parameters T\({}_{\text{on}}\) obtained for five rates of heating sample during the thermo-oxidative processes of interesterified fats. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**T\({}_{\text{on}}\) Based Value**} \\ \cline{2-4}  & **LR70\_4** & **LR70\_8** & **LR70\_24** \\ \hline a & \(-\)4912.3 & \(-\)5090.0 & \(-\)4949.3 \\ b & 12.33 & 12.46 & 12.10 \\ R\({}^{2}\) & 0.96 & 0.96 & 0.99 \\ E\({}_{\text{a}}\) & 89.40 & 92.63 & 90.07 \\ Z & 4.08 \(\times\) 1010 & 4.41 \(\times\) 1010 & 1.93 \(\times\) 1010 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Statistical and kinetic parameters characterizing thermal-oxidative decomposition of inter-esterified fats. Ea—activation energy (kJ/mol), \(Z\)—pre-exponential factor. stearic acid [12]. Rapeseed oil (RO) contains twice as many of MUFA and PUFA compared to HMF. The addition of the rapeseed oil to lard increased the unsaturated FAs contents. Brest milk fat contains about 40.6% of the SFA 39.1% of the MUFA and 19.5% of the PUFA [30], while in the case of obtained SL, SFA amount was determined at the level of from 40.2 to -41.9%, MUFA-from 44.7-46.2%, and PUFA-13.4-13.6%, including significant essential FAs from n-3 group and from n-6 group, like \(\alpha\)-linolenic acid and linoleic acid. Content of oleic and palmitic acid for obtained SL is similar to HMF. Obtained SL does not contain valuable DHA, EPA, ARA, but it is a source of precursors of these FAs. FAs such as DHA, EPA, and ARA can be formed in the human body by metabolism of FAs, i.e., \(\alpha\)-linolenic acid and linoleic acid. Therefore, the enzymatic modification of a mixture of lard and rapeseed oil allows for an accumulation of new fats with oleic and palmitic acids at quantities comparable to HMF, as well as containing crucial essential FA from the omega-3 group. The types of FAs and its distribution in the molecule of TAG affect the physical properties of fats as well as the behavior of fats during digestion and absorption [36; 37]. Breast milk contains approximately 70% palmitic acid in the middle position of TAG, while in most vegetable oils this FA is located in the outer positions of the TAG. Taking into account the obtained results, it can be concluded that lard, like HMF, contains about 85.3% palmitic acid in the internal position of TAG, while the percentage of this FA in the internal TAG position in RO was only 23.3%.