## 3 Results and Discussion
### Analysis of Lipid Fraction Extracted from Model Meat Batters  
The fatty acid compositions of the model meat batters is presented in Table 2. The incorporation of mixtures of MF:RSO and iMF:RSO in the recipe of model meat batters significantly changed the fatty acid composition compared with the control meat batters. It was found that meat batters MB_MF:RSO and MB_iMF:RSO were characterized by higher contents of polyunsaturated fatty acids (PUFA) and lower saturated fatty acids than the control meat batter (with pork jowl). In MB_MF:RSO and MB_iMF:RSO, the content of PUFA reached 18.24% and 18.54%, respectively, while, in the MB_C, 10.26%. The results revealed that the control meat batters were characterized by a higher amount of palmitic and stearic acids and lower amounts of linoleic and \(\alpha\)-linoleic acids than the meat batters with MF:RSO and iMF:RSO. The amount of oleic acid was at a similar level in all meat batters. In the case of the control meat batters, the lower values of the medium and short-chain fatty acids were determined. Medium-chain fatty acids are used in the body as a source of energy for the muscles, heart, liver, kidneys and platelets. They are also a source of fast energy, because they are easily absorbed in the small intestine and then transported through the portal vein to the liver, in which they are immediately metabolized [5]. Generally, the composition of fatty acids of model meat batters closely correlated with the types of fats used for their production. The amounts of individual fatty  
Figure 3: Acid value (AV) and induction time of fats used in model meat batters and extracted from model meat batters. Different letters indicate that the samples are considered significantly different at the 5% level (\(p\) < 0.05). MF:RSO—noninteresterified mixture of milkfat and rapeseed oil, iMF:RSO—interesterified mixture of milkfat and rapeseed oil, MB_C—control meat batters with pork jowl, MB_MF:RSO—meat batters produced with a noninteresterified mixture of milkfat and rapeseed oil and MB_iMF:RSO—meat batters produced with an interesterified mixture of milkfat and rapeseed oil. acids of the batters with the noninteresterified and interesterified mixtures were at similar level as in fats used for the production of batters. A previous study also reported that the replacement of animal fat with interesterified mixtures containing vegetable oil resulted in a more favorable from nutritional point of view ratio of unsaturated fatty acids to SFAs in the model meat batters [13], dry-fermented sausages [5], frankfurters [6] and sausages [11]. The distribution of fatty acids in the lipid fraction from the model meat batters reflects the distribution of these fatty acids in the appropriate fat mixtures used for the production of the mentioned products (Figure 1). The absorption of fatty acids in the intestinal lumen can be improved by achieving a specific distribution of fatty acids. If saturated fatty acids are esterified at the internal position of TAG, they are absorbed more efficiently compared to the saturated fatty esterified in the external positions of TAG [28]. Such modified lipids can be used in the production of special purpose foods. Studies on obtaining interesterified lipids with the desired compositions and distribution of fatty acids and, consequently, dealing with designing new products with predetermined properties seem to be particularly interesting [5; 6; 23]. The content of free fatty acids was higher in fats isolated from the model meat batters than in fats used in the recipe of the meat batters (Figure 3). Fat from the meat batters was also characterized by lower oxidative stability than the corresponding fat mixtures. The reduction of oxidative stability may be caused by the hydrolysis of ester bonds in triacylglycerol molecules under the influence of water contained in the batters. The products of hydrolysis--mainly, free fatty acids--can induce an oxidation reaction.