# Changes in Selected Properties of Cold-Pressed Oils Induced by Natural Plant Additives
## 3 Results and Discussion
### Chemical Determination of Oils  
Table 2 summarizes the results of the content of individual fatty acids, their groups, and the n-6 to n-3 acid ratio. The highest content of saturated fatty acids (SFAs) in the total fatty acid pool was observed in the black cumin seed oil (15.94%). The level of SFAs in the other oils was substantially lower, i.e., 7.16% and 9.61% in the hemp and flax seed oil, respectively. Monounsaturated acids (MUFAs) (Table 2) represented by oleic acid from the n-9 family were present at the level of 13.23% (hemp oil) to 23.98% (black cumin seed oil). The total content of polyunsaturated fatty acids (PUFAs) in the oils was substantially higher than that of MUFAs and ranged from 60.08% to 79.61%. The black cumin seed oil had the lowest amount of these acids, whereas the hemp seed oil showed the highest level; in both cases, these acids were mainly n-6 acids (59.65% and 58.21%, respectively). The flax seed oil was found to have a higher content of n-3 acids (56.94%) and a lower content of n-6 acids (15.96%) (Table 2). \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** & **Moisture (\(\pm\) SD) [\%]** & **Fat Content (\(\pm\) SD) [\%]** & **Protein Content (\(\pm\) SD) [\%]** \\ \hline Flax seeds & 6.64 \(\pm\) 0.07 \({}^{\star}\) & 35.98 \(\pm\) 0.05 \({}^{\star}\) & 26.35 \(\pm\) 0.06 \({}^{\star}\) \\ Hemp seeds & 5.93 \(\pm\) 0.06 \({}^{\text{b}}\) & 29.98 \(\pm\) 0.04 \({}^{\text{b}}\) & 31.05 \(\pm\) 0.06 \({}^{\text{b}}\) \\ Black cumin seeds & 6.33 \(\pm\) 0.05 \({}^{\star}\) & 37.93 \(\pm\) 0.06 \({}^{\text{c}}\) & 20.21 \(\pm\) 0.05 \({}^{\text{c}}\) \\ \hline \hline \end{tabular} \({}^{\star}\)Values designated by the different small letters in the column are significantly different (\(\alpha=0.05\)).  
\end{table} 
Table 1: Basic chemical composition of seeds. The appropriate ratio of n-6 to n-3 fatty acids in the diet recommended by nutritionists is 4:1 [27]. It is maintained at very high contents of fatty acids from both families. Only the black cumin seed oil among the analyzed samples had a very small amount of n-3 fatty acids (0.43%); therefore, the ratio of n-6 to n-3 fatty acids was unfavorable, i.e., 138.7:1 (Table 2). An excess amount of omega-6 fatty acids in the diet leads to the development of chronic inflammation, which can lead to specific diseases, e.g., malignant neoplasms, skin diseases, or cardiovascular and nervous system diseases [28]. A substantially lower n-6 to n-3 ratio resulting from the higher amounts of both n-6 and n-3 fatty acids was determined in the hemp seed oil (3.2:1). The ratio was 1:3.6 in the flax seed oil. [PERSON] et al. also analyzed the fatty acid composition in _Nigella damascena_ depending on the sowing date and seed origin. Their result differed from the fatty acid profile detected in the present study (Table 2). The largest differences were noted in the amounts of SFAs, i.e., their level reported by [PERSON] et al. [26] was twice as high (31.40% in the oil extracted from commercial seeds and 32.33% in the oil from seeds from the first sowing term). The authors observed lower values of unsaturated fatty acids, with 8.09% and 15.06% differences in MUFAs and PUFAs, respectively. A fatty acid composition in black cumin seed oil similar to that determined in the present study was reported by [PERSON] and [PERSON] [1] in their analyses of various cold-pressed oils. The contents of SFAs, MUFAs, and PUFAs were 15.76%, 23.99%, and 59.77%, respectively, compared to 15.94%, 23.98%, and 60.08%, respectively, determined in the present study. The same authors also analyzed the composition of flax seed oil. They detected 9.15% of SFAs mainly represented by palmitic acid (5.8%). MUFAs accounted for 17.43% (oleic acid), and PUFAs constituted 72.75% of the content, including 15.82% of linoleic acid and 56.93% of \(\alpha\)-linolenic acid. The ratio of n-6 to n-3 acids in their study was 0.3 vs. 0.28 determined in the present study (Table 2).