## 3 Results and Discussion
### Oxidative Stability

Table 3: [PERSON]’s linear correlation of maximum oxidation time (\(y\)) and content of oleic and polyunsaturated fatty acids (\(x\)) regarding each measurement temperature. The graphical relationship between the logarithm of the maximum recorded oxidation time (\(\tau\)) and the reciprocal of the temperature (in absolute scale) has been presented in Figure 4. Due to the fact that the data in the equations presented in Figure 4 show a linear relationship (R\({}^{2}\) coefficients above 0.98; Table 4), the kinetic parameters of the oxidation reaction can be calculated on this basis (Table 4). The activation energy of the tested oils reached 96.21 kJ/mol for the A1 oil, 99.48 kJ/mol for the A2 oil, and 83.86 kJ/mol and 80.74 kJ/mol for the P1 and P2 oils, respectively (Table 4). Despite the fact that the apricot kernel oils were characterized by significantly different maximum oxidation times, no significant differences in the activation energy values were found for them. [PERSON] et al. [43] stated that the activation energy value strongly depends on the fatty acid profile. A high proportion of saturated and monounsaturated acids may increase the activation energy of the oxidation reaction, while a low proportion of polyunsaturated acids may lower the activation energy. This rule was not observed in the case of the apricot kernel oils. Although oil A1 was characterized by a higher content of oleic acid and lower content of linoleic acid than the A2 oil, both oils were characterized by similar values of activation energy. In this case, the content of pro- or antioxidant ingredients could have influenced the activation energy value. Peach kernel oils P1 and P2 were characterized by similar values of activation energy; in these cases, the shares of oleic and linoleic acid were also similar. Comparatively, previous studies of lipid oxidation kinetics for non-typical oils presented similar Ea values calculated for avocado oil at 99.6 kJ/mol [46], rose hip oil at 94.74-105.85 kJ/mol [45], sea buckthorn oil at 87.23-93.93 kJ/mol [36], quinoa seed oil at 77.75 kJ/mol [44], and amaranth seed \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & **A1** & **A2** & **P1** & **P2** \\ \hline a & 5.2817 \(\pm\) 0.122 & 5.4393 \(\pm\) 0.116 & 4.6051 \(\pm\) 0.047 & 4.4275 \(\pm\) 0.193 \\ b & 11.273 \(\pm\) 0.318 & 12.294 \(\pm\) 0.338 & 9.729 \(\pm\) 0.117 & 9.4209 \(\pm\) 0.507 \\ R\({}^{2}\) & 0.9986 \(\pm\) 0.004 & 0.9875 \(\pm\) 0.025 & 0.9812 \(\pm\) 0.003 & 0.9861 \(\pm\) 0.003 \\ Ea (kJ/mol) & 96.21 \(\pm\) 2.23 b & 99.48 \(\pm\) 2.12 b & 83.86 \(\pm\) 0.56 a & 80.74 \(\pm\) 3.52 a \\ Z & 3.401 \(\times\) 10\({}^{9}\) & 3.396 \(\times\) 10\({}^{10}\) & 1.097 \(\times\) 10\({}^{8}\) & 5.608 \(\times\) 10\({}^{7}\) \\ k at 100 \({}^{\circ}\)C & 0.000116 & 0.000403 & 0.000200 & 0.000283 \\ k at 110 \({}^{\circ}\)C & 0.000260 & 0.000930 & 0.000405 & 0.000557 \\ k at 120 \({}^{\circ}\)C & 0.000560 & 0.002057 & 0.000791 & 0.001061 \\ k at 130 \({}^{\circ}\)C & 0.001161 & 0.004377 & 0.001495 & 0.001958 \\ k at 140 \({}^{\circ}\)C & 0.002327 & 0.008978 & 0.002739 & 0.003507 \\ \hline \hline \end{tabular} Data denoted by the same lowercase letters are not statistically different (\(\alpha\) = 0.05) in terms of activation energy.  
\end{table} 
Table 4: Kinetic parameters (a and b—adjustable coefficients, Ea—activation energy, Z—pre-exponential factor, and k—reaction rate coefficient) of oxidation of peach and apricot kernel oils. Figure 4: Log maximum oxidation time versus reciprocal temperature of apricot kernel oils (**a**) and peach kernel oils (**b**). oil at 80.82 kJ/mol [43]. As expected, the results indicate that k increases with increasing temperature, corroborating the known effect of high temperature in the improvement of lipid oxidation. The values of the k parameter calculated by other authors indicated the same relationship [44; 46].