# Increasing the Bioactive Compound Content of Olive Oil by Acidification of Olive Paste
## 3 Results
### Phenolic Compounds and Antioxidant Capacity
\begin{table}
\begin{tabular}{l c c c c c} \hline \multicolumn{1}{c}{**Acid**} & \multicolumn{1}{c}{**Hydroxytyrosol**} & \multicolumn{1}{c}{**Tyrosol**} & \multicolumn{1}{c}{**Apigenin**} & \multicolumn{1}{c}{**Luteolin**} & \multicolumn{1}{c}{**Pinoresinol**} \\ \hline Control (0\%) & 2.20 \(\pm\) 0.21 \({}^{\text{g}}\) & 1.60 \(\pm\) 0.20 \({}^{\text{c}}\) & 1.64 \(\pm\) 0.23 \({}^{\text{f}}\) & 4.33 \(\pm\) 0.30 \({}^{\text{b}}\) & 17.85 \(\pm\) 0.66 \({}^{\text{abcd}}\) \\ Acetic (1\%) & 2.60 \(\pm\) 0.07 \({}^{\text{fg}}\) & 1.39 \(\pm\) 0.09 \({}^{\text{cd}}\) & 2.12 \(\pm\) 0.20 \({}^{\text{ef}}\) & 3.67 \(\pm\) 0.30 \({}^{\text{bc}}\) & 18.68 \(\pm\) 0.30 \({}^{\text{abc}}\) \\ Acetic (2\%) & 3.46 \(\pm\) 0.13 \({}^{\text{cd}}\) & 1.62 \(\pm\) 0.17 \({}^{\text{c}}\) & 2.55 \(\pm\) 0.33 \({}^{\text{de}}\) & 3.36 \(\pm\) 0.23 \({}^{\text{c}}\) & 16.43 \(\pm\) 1.07 \({}^{\text{cd}}\) \\ Acetic (4\%) & 5.13 \(\pm\) 0.40 \({}^{\text{a}}\) & 2.86 \(\pm\) 0.37 \({}^{\text{a}}\) & 2.59 \(\pm\) 0.21 \({}^{\text{cde}}\) & 3.86 \(\pm\) 0.35 \({}^{\text{bc}}\) & 15.85 \(\pm\) 1.82 \({}^{\text{d}}\) \\ Ascorbic (1\%) & 3.03 \(\pm\) 0.35 \({}^{\text{def}}\) & 0.86 \(\pm\) 0.10 \({}^{\text{e}}\) & 4.97 \(\pm\) 0.41 \({}^{\text{a}}\) & 5.21 \(\pm\) 0.40 \({}^{\text{a}}\) & 19.41 \(\pm\) 1.22 \({}^{\text{ab}}\) \\ Ascorbic (2\%) & 3.18 \(\pm\) 0.06 \({}^{\text{de}}\) & 0.77 \(\pm\) 0.06 \({}^{\text{e}}\) & 3.23 \(\pm\) 0.41 \({}^{\text{c}}\) & 5.28 \(\pm\) 0.31 \({}^{\text{a}}\) & 17.14 \(\pm\) 0.41 \({}^{\text{b}}\) \\ Ascorbic (4\%) & 3.91 \(\pm\) 0.29 \({}^{\text{c}}\) & 1.00 \(\pm\) 0.07 \({}^{\text{de}}\) & 2.70 \(\pm\) 0.35 \({}^{\text{de}}\) & 5.93 \(\pm\) 0.73 \({}^{\text{a}}\) & 17.54 \(\pm\) 0.28 \({}^{\text{abcd}}\) \\ Citric (1\%) & 2.83 \(\pm\) 0.13 \({}^{\text{ef}}\) & 2.19 \(\pm\) 0.13 \({}^{\text{b}}\) & 2.92 \(\pm\) 0.16 \({}^{\text{cd}}\) & 3.79 \(\pm\) 0.28 \({}^{\text{bc}}\) & 18.61 \(\pm\) 0.87 \({}^{\text{abc}}\) \\ Citric (2\%) & 3.00 \(\pm\) 0.156 \({}^{\text{def}}\) & 2.68 \(\pm\) 0.26 \({}^{\text{a}}\) & 2.57 \(\pm\) 0.25 \({}^{\text{de}}\) & 3.76 \(\pm\) 0.31 \({}^{\text{bc}}\) & 19.40 \(\pm\) 0.81 \({}^{\text{ab}}\) \\ Citric (4\%) & 4.55 \(\pm\) 0.12 \({}^{\text{b}}\) & 2.56 \(\pm\) 0.09 \({}^{\text{ab}}\) & 4.28 \(\pm\) 0.41 \({}^{\text{b}}\) & 5.44 \(\pm\) 0.64 \({}^{\text{a}}\) & 19.54 \(\pm\) 1.99 \({}^{\text{a}}\) \\ \hline [PERSON]’s LSD ** & 0.46 & 0.39 & 0.65 & 0.84 & 2.36 \\ \hline \end{tabular} \({}^{\text{a}}\) Mean and standard deviation of three replicates. ** For each column, superscript letters indicate statistical groupings based on [PERSON]’s least significant difference (LSD) test. Different letters denote statistically significant differences, while identical letters indicate no significant difference at the 95% confidence level.  
\end{table} 
Table 3: Phenolic alcohol, flavonoid, and lignin contents in oils, mg/kg \({}^{\text{*}}\). Table 4 presents the secoiridoid and total phenolic contents, along with the antioxidant capacity of the olive oils, as determined by the FRAP method. All secoiridoids originate from the hydrolysis of oleuprein and ligstroside. Among these compounds, oleuprein derivatives were the most abundant across all produced oils, particularly oleacein (3,4-DHPEA-EDA) and its precursor, oleuprein aglycone (3,4-DHPEA-EA). Ligstroside derivatives, including oleocanthal (\(p\)-HPEA-EDA) and its aglycone (\(p\)-HPEA-EA), were present at lower concentrations. Like the prior tables, Table 4 incorporates statistical analysis, using superscript letters to differentiate means within each column based on [PERSON]'s LSD (\(p<0.05\)).