## 3 Results and Discussion
### Sterol Content in Olive Oils
Similarly, [PERSON] et al. [10] observed that conventional olive oils had a higher radical scavenging capacity, ranging from 0.53 to 2.41 umol TE/g values. [PERSON] et al. [34] also measured DPPH values in conventional olive oils, which ranged between 0.36 and 0.62 umol TE/g. Figure 3 presents the results of the antioxidant activity of the olive oils as measured by the FRAP assay. The ferric ion-reducing capacity of the analyzed olive oil extracts ranged from 0.19 to 0.30 umol TE/g. The highest values were observed in extracts from conventional olive oil samples nos. 6, 7, and 8, while the lowest were recorded in organic samples nos. 2, 3, and 5. The olive oils derived from conventional cultivation differed significantly from those obtained from organic farming (Figure 3). Additionally, the data in Figure 3 confirm the presence of statistically significant differences (\(p<0.05\)) in the  
Figure 2: Value of the ability of olive oil extracts from organic and conventional farming to deactivate stable DPPH radicals expressed as [μmol TE/g of olive oil]. Data are the means of three independent experiments \(\pm\) standard deviations (n = 3). a–c values in the bars with different lowercase letters indicate a significant difference at the 0.05 significance level (Tukey HSD). ferric ion-reducing capacity of extracts obtained from olive oils produced using different cultivation systems (three of the four products). In the study by [PERSON] et al. [35], conventional olive oils showed FRAP values ranging from 0.32 to 1.12 umol TE/g. Similarly, [PERSON] et al. [36] reported values ranging from 0.11 to 0.90 umol TE/g, while [PERSON] et al. [37] reported FRAP values for conventional olive oils between 0.38 and 1.67 umol TE/g. The analysis of phenolic acid content showed that the total content of phenolic acids (oleuropein, hydorovytrosol, and tyrosol) ranged from 133.20 (olive no. 7) to 226.82 mg/kg (olive no. 6). Oleuropein content was found to be slightly higher in olives derived from conventional farming and ranged from 75.92 to 100.05 mg/kg, while its content in olive oils derived from organic farming was between 58.89 and 90.77 mg/kg (Table 4). The opposite observation was reported for hydroxyytrosol content, and, for olives derived from conventional farming, ranged from 3.56 to 56.23 mg/kg, while olive oils derived from organic farming had a hydroxyytrosol content that ranged from 42.99 to 59.35. The concentration of tyrosol in the analyzed olive oils samples was between 44.97 and 82.45 mg/kg. The highest amount of tyrosol was found in extra virgin olive oils no. 6 (conventional), no. 4 (organic), and no. 1 (organic). The content of particular phenolic acids does not correlate with DPPH antiradical capacity or FRAP iron ion reduction. According to that observation, the DPPH antiradical capacity or FRAP iron ion reduction capacity of olive oil is not related to the presence of the aforementioned phenolic acids. [PERSON] et al. [10] reported that the tyrosol content in Italian olive oils varied depending on the area where the olives were cultivated, e.g., in Sicily, the range was between 0.03 and 62.30 mg/kg, while in Lazio it was between 0.34 and 12.83 mg/kg. The same observation applied to hydroxyytrosol, because the olive oil derived from Sicily contained 9.20-62.7 mg, and, on the other hand, olive oil from Tuscany contained 0.72-38.64 mg hydroxyytrosol per 1 kg. [PERSON] et al. [10] found many different oleuropein aglycones in Italian olives; their content could range from 747.46 to 74.46. Figure 3: The ability of olive oils from organic and conventional farming to reduce iron ions, measured by the FRAP method and expressed as [umol TE/g of olive oil]. Data are the means of three independent experiments \(\pm\) standard deviations (n = 3). a–b values in the bars with different lowercase letters indicate a significant difference at the 0.05 significance level (Tukey HSD). 1682.89 mg/kg in Puglia olive oils.