## 3 Results and Discussion  
### Analysis of Interesterified and Noninteresterified Mixtures  
The fatty acid compositions in the initial (MF:RSO) and interesterified (iMF:RSO) mixtures are given in Table 2.  
Interesterification did not change the fatty acid compositions in the analyzed formulas. In the interesterified mixture, the share of individual fatty acids (FA) was found at a similar amount as in the initial fat mixture. Among the saturated fatty acids, palmitic acid was present in a dominant amount: 16.50% in MF:RSO and 15.39% in iMF:RSO. The major unsaturated fatty acids were oleic (48.36% in MF:RSO and 47.55% in iMF:RSO) and  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Fatty Acid** & **MF:RSO** & **iMF:RSO** & **MB\_C** & **MB\_MF:RSO** & **MB\_iMF:RSO** \\ \hline C4:0 & 0.34 \(\pm\) 0.12 \({}^{\text{a}}\) & 0.54 \(\pm\) 0.12 \({}^{\text{a}}\) & - & 0.36  
linoleic acid (11.85% in MF:RSO and 12.52% in iMF:RSO). In both mixtures, \(\alpha\)-linolenic acid derived from rapeseed oil was also found. Its amount was at the level of 5.10% in the noninteresterified mixture and 5.59% in the interesterified fat. It is worth emphasizing that interesterification does not cause the isomerization of fatty acids and does not affect the degree of unsaturation [17; 20; 21; 22]. Interesterification is a method of modifying the functionality of fats and oils [23]. The monitoring of the changes in interesterified fats is extremely useful and can be an indication about how the randomization process takes place [24]. In Figure 1, the analysis of fatty acids in the sn-2 position of the triacylglycerors is presented. The enzymatic preparation used in this experiment contains a regiospecific lipase. Thus, enzymatic interesterification should proceed only in the sn-1,3 position of triacylglycerors; the sn-2 position should remain unchanged [25; 26]. In noninteresterified and interesterified fats, palmitic acid was mainly esterified in the sn-2 position (36.81% and 42.91%, respectively). The amount of unsaturated fatty acids in external positions (sn-1,3) in interesterified fats increased compared to the corresponding noninteresterified mixture. The percentage of unsaturated fatty acids in the internal position of TAG (triacylglycerol) in MF:RSO is 47.26% for linoleic acid and 45.29% for \(\alpha\)-linolenic acid, whereas, in iMF:RSO, reaches 27.02% and 24.81% for linoleic and \(\alpha\)-linolenic acid, respectively. The apparent lack of selectivity in the interesterification reaction catalyzed by the regiospecific lipase is due to the fact that the enzyme attacks mainly TAG at the sn-1,3 positions of the glycerol, yielding 1,2- and 2,3-diacylglycerolcels (DAGs), leaving the sn-2 position unchanged. The FA at the sn-2 position of the 1,2- and 2,3-DAG can spontaneously migrate, yielding the more stable 1,3-DAG [25]. It could result in reducing the amount of C18:2 and C18:3 acids in the sn-2 position of TAG in iMF:RSO. The rate and extent of fatty acid absorption depends on the stereochemistry of the modified lipids [27]. The pancreatic lipases release fatty acids from the sn-1 and sn-3 positions of TAG, giving free fatty acids and a molecule of 2-monoacylglycerol, which are then absorbed. Studies of rats and human infants suggested that palmitic and stearic acids may be better absorbed when they are retained within 2-monoacylglycerolcerol during digestion [23; 28]. The melting profile determined the sensory characteristics of the final modified fat mixture. The melting curves of the blends before and after interesterification are presented  
Figure 1: The percentage of fatty acids in the sn-2 position of the initial and interesterified fats and fats extracted from the model meat batters.