## 3 Results and Discussion
### Oxidation Shelf-Life Study of Beef Burgers  
Table 5 summarizes the evolution in pH and color measurements of the beef burgers throughout the shelf-life study, as well as after cooking on the day of elaboration. Overall, pH values decreased in all formulations over the 3 days of refrigerated storage. However, this decrease was more pronounced in the control formulation, with significant differences observed between days 0 and 3. Such a decrease in pH could be attributed to a possible microbial growth during storage. Nevertheless, the pH values for the remained formulations, especially those containing artichoke, were not significantly decreased. These effects have also been reported by other authors using propyl [63], oregano [64], and rosemary [65] in the preservation of beef burgers. \begin{table} \begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**TPC**} & \multicolumn{4}{c}{**Antioxidant Activity**} \\ \cline{3-5}  & & **FRAP** & **DPPH** & **ABTS** \\ \hline AE & 161.20 \(\pm\) 10.79 & 334.00 \(\pm\) 11.27 & 357.92 \(\pm\) 11.44 & 189.36 \(\pm\) 8.74 \\ TAE & 172.02 \(\pm\) 0.97 & 328.49 \(\pm\) 41.23 & 342.05 \(\pm\) 8.91 & 193.24 \(\pm\) 0.35 \\ Raw burgers & & & & \\ CB & 1.01\(\pm\) 0.07 \({}^{\text{c},\text{y}}\) & 1.96 \(\pm\) 0.16 \({}^{\text{c},\text{y}}\) & 2.39 \(\pm\) 0.06 \({}^{\text{b},\text{y}}\) & 2.51\(\pm\) 0.30 \({}^{\text{c},\text{y}}\) \\ FRB & 1.04 \(\pm\) 0.04 \({}^{\text{c},\text{y}}\) & 5.97 \(\pm\) 0.32 \({}^{\text{b},\text{y}}\) & 2.85 \(\pm\) 1.25 \({}^{\text{b},\text{y}}\) & 5.58 \(\pm\) 0.16 \({}^{\text{b},\text{y}}\) \\ FRB-AE & 4.21 \(\pm\) 0.03 \({}^{\text{b},\text{x}}\) & 19.73 \(\pm\) 0.34 \({}^{\text{a},\text{y}}\) & 12.10 \(\pm\) 0.62 \({}^{\text{a},\text{x}}\) & 15.19 \(\pm\) 0.26 \({}^{\text{a},\text{x}}\) \\ FRB-TAE & 4.45 \(\pm\) 0.01 \({}^{\text{a},\text{y}}\) & 20.39 \(\pm\) 1.37 \({}^{\text{a},\text{y}}\) & 11.70 \(\pm\) 2.80 \({}^{\text{a},\text{y}}\) & 15.42 \(\pm\) 0.15 \({}^{\text{a},\text{y}}\) \\ Cooked burgers & & & & \\ CB & 2.44 \(\pm\) 0.05 \({}^{\text{c},\text{x}}\) & 4.67 \(\pm\) 0.20 \({}^{\text{c},\text{x}}\) & 4.86 \(\pm\) 0.09 \({}^{\text{c},\text{x}}\) & 5.60 \(\pm\) 0.25 \({}^{\text{c},\text{x}}\) \\ FRB & 2.22 \(\pm\) 0.10 \({}^{\text{c},\text{x}}\) & 6.95 \(\pm\) 0.28 \({}^{\text{c},\text{x}}\) & 5.56 \(\pm\) 0.15 \({}^{\text{c},\text{x}}\) & 6.15 \(\pm\) 0.29 \({}^{\text{c},\text{x}}\) \\ FRB-AE & 5.80 \(\pm\) 0.29 \({}^{\text{b},\text{x}}\) & 19.87 \(\pm\) 0.62 \({}^{\text{b},\text{x}}\) & 15.53 \(\pm\) 1.96 \({}^{\text{b},\text{x}}\) & 16.65 \(\pm\) 0.39 \({}^{\text{b},\text{x}}\) \\ FRB-TAE & 6.88 \(\pm\) 0.32 \({}^{\text{a},\text{x}}\) & 24.30 \(\pm\) 1.70 \({}^{\text{a},\text{x}}\) & 18.74 \(\pm\) 1.30 \({}^{\text{a},\text{x}}\) & 20.21 \(\pm\) 1.12 \({}^{\text{a},\text{x}}\) \\ \hline \hline \end{tabular}   
Regarding the color measurements, also represented in Table 5, there were significant differences (\(p<0.05\)) between the results of the L\({}^{*}\), a\({}^{*}\), and b\({}^{*}\) coordinates between products, indicating that the reformulations influenced the color of the beef burgers. FRB presented a significant change in a\({}^{*}\), highlighting a loss of reddish color due to the substitution of fat by EVOO. There is some debate regarding color changes when substituting fat with hydrogel emulsions in beef burgers. This may be due to the color of the oil used or the composition of the emulsifiers or jellifying agents. Moretto et al. (2016) found no color differences in buffalo burgers where olive oil replaced beef fat, but other authors have reported differences in a\({}^{*}\) or L\({}^{*}\) when substituting beef fat with cocoa (2012) or pumpkin seed oils (2015). In addition, there were significant differences in L\({}^{*}\) and a\({}^{*}\) for the burgers containing artichoke extracts, being reduced in both cases.