## 3 Results and Discussion
### Total Phenolic Content (TPC) and Antioxidant Capacity  
The total phenolic content measured by the Folin-Ciocalteu assay, and the antioxidant activity (FRAP, ABTS, and DPPH) of the artichoke extracts and raw and cooked beef burgers are shown in Table 4. Artichoke extracts exhibited a high amount of phenolic compounds (162.20-172.02 mg GAE/g). These results are higher than those found in the literature [53; 54], demonstrating the high efficiency of the extraction process. In addition, the extracts also showed a high antioxidant capacity in the three assays described, with the ABTS and DPPH values higher than those of other vegetables, such as broccoli, lettuce, or spinach [55].  
This high antioxidant activity may be due to the high content of TPC found in the extracts. It is known that artichoke is a great source of hydroxycinnamic acids derived from caffe acid and flavonoids such as luteolin and apigenin [56]. Furthermore, no significant differences in antioxidant activity and TPC were observed following the enzymatic treatment of the artichoke extracts.  
\begin{table}
\begin{tabular}{c c c c c} \hline  & **CB** & **FRB** & **FRB-AE** & **FRB-TAE** \\ \hline n-6 & 2.97 \(\pm\) 0.07 b  & 4.51 \(\pm\) 0.69 ab  & 5.12 \(\pm\) 0.76 a  & 4.73 \(\pm\) 0.27 ab  \\ C18:3n-3 & 0.13 \(\pm\) 0.00 b  & 0.23 \(\pm\) 0.06 ab  & 0.30 \(\pm\) 0.06 a  & 0.30 \(\pm\) 0.06 a  & 0.30 \(\pm\) 0.01 a  & 0.14 \(\pm\) 0.01 a  & 0.13 \(\pm\) 0.01 a  & 0.14 \(\pm\) 0.01 a  & 0.13 \(\pm\) 0.01 a  & 0.14 \(\pm\) 0.01 a  & 0.13 \(\pm\) 0.00 a  & 0.05 \(\pm\) 0.00 a  & 0.05 \(\pm\) 0.00 a  & 0.09 \(\pm\) 0.03 a  & 0.09 \(\pm\) 0.03 a  & 0.39 \(\pm\) 0.04 a  & 0.49 \(\pm\) 0.06 a  & 0.52 \(\pm\) 0.01 a  & 0.39 \(\pm\) 0.04 a [FOOTNOTE:a]Footnote a: Different lettersRegarding raw burgers, significant differences (\(p<0.05\)) were observed in FRB for ABTS and FRAP assays in relation to CB. However, no increase in TPC was observed. EVOO is considered a great source of compounds with antioxidant activity, such as tocopherols or hydroxytyrosol and derivatives (oleuropein and tyrosol), as well as other compounds including hydrocarbons (i.e., squalene) and pigments like provvitamin A [16]. Therefore, its inclusion in the hydrogel emulsion can improve the antioxidant capacity of the beef burgers. Similar effects were also shown by Dominguez et al. [57] reporting higher amounts of \(\alpha\)-tocopherol after the replacement of gate fat with olive oil.  
A significant increase was observed in the burgers with added artichoke extract (\(p<0.05\)) for both phenolic content and antioxidant activity. These increases in relation to CB were 417-441% for TPC, 1001-1040% for FRAP, 490-506% for DPPH, and 605-614% for ABTS. Ergeezer et al. [27] tested the effect of the addition of 50 and 100 ppm artichoke extract in beef patties, obtaining similar results with a substantial increase in DPPH and TPC values. Many studies have shown that the use of vegetable extracts such as kiwi [58], pomergnate [59], guarana [60], or grapes [61] can enhance the antioxidant capacity of meat products.  
Finally, the results for TPC and antioxidant capacity in cooked burgers were studied to test the resistance to cooking of the bioactive compounds present in artichoke and EVOO. However, a significant increase was observed in all formulations. These results may be due to moisture loss during cooking, which in beef burgers can reach up to 45% in relation to the raw sample [62].