## 3 Results and Discussion
### Antioxidant Composition and Oxidative Status  
Mean values for both \(\alpha\)- and \(\gamma\)-tocopherol, total antioxidant activity and oxidative status, are shown in Table 6. \(\alpha\)- and \(\gamma\)-tocopherol showed higher values in burgers made with pecan nuts with respect to control samples (\(p<0.05\) and \(p<0.001\) respectively), mainly \(\gamma\)-tocopherol, whose values ranged from 0.16 mg/kg in control burgers to 27.74 mg/kg in burgers made with 10% pecan nuts. These values increased progressively as the amount of pecan nuts increased in the formulation. This is due to the high value of tocopherols (in the form of vitamin E) in nuts, including pecan nuts [41]. Total antioxidant activity also increased gradually in burgers as the amount of pecan nuts in their composition increased (\(p<0.001\)). However, in other studies on hamburgers, a trend contrary to that found in the current study was reported [56].  
Regarding lipid oxidation, the addition of pecan nuts to the burger formulation had an impact on MDA content (\(p<0.001\)). Higher PUFA values in burgers made with pecan nuts increased the risk of oxidation in burgers. However, TBAR values decreased in burgers formulated with pecan nuts. This decrease is explained by the high polyphenol content of pecan nuts [41]. Thus, as the percentage of pecan nuts in the burgers increases, a decrease in lipid oxidation will be reported. Our lipid oxidation values are lower than the values described by De Carvalho et al. [57], who reported values between 7 and 10 mg MDA/kg in lamb burgers reformulated with chia emulsion. The same pattern was found in the protein oxidation values, which were lower in burgers enhanced with pecan nuts with respect to the control samples (\(p<0.05\)). This is evidence of the efficacy of the natural antioxidant properties of pecan nuts over other synthetic antioxidants, as reported by some authors [9; 58].  
\begin{table}
\begin{tabular}{l c c c c c c} \hline  & & \multicolumn{4}{c}{**With Pecan**} & \multirow{2}{*}{**SEM**} & \multirow{2}{*}{**\(p\)-Value**} \\ \cline{3-3} \cline{5-6}  & & **5\%** & **10\%** & & **15\%** & \\ \hline C16:0 & 24.41 a & 21.04 b & 19.07 c & 17.17 d & 0.49 & 0.000 \\ C18:0 & 15.56 a & 13.04 b & 11.64 c & 10.57 d & 0.34 & 0.000 \\ C18:1 & 45.53 d & 49.82 c & 52.45 b & 54.75 a & 0.63 & 0.000 \\ C18:2 n-6 & 3.53 d & 6.45 c & 8.49 b & 10.246 a & 0.46 & 0.000 \\ C18:3 n-3 & 0.41 d & 0.58 c & 0.68 b & 0.76 a & 0.03 & 0.000 \\ SFA & 43.75 a & 37.25 b & 33.47 c & 30.06 d & 0.93 & 0.000 \\ MUFA & 49.50 d & 53.33 c & 55.52 b & 57.18 a & 0.53 & 0.000 \\ PUFA & 3.94 d & 7.03 c & 9.17 b & 11.01 a & 0.49 & 0.000 \\ PUFA/SFA & 0.09 d & 0.19 c & 0.27 b & 0.37 a & 0.02 & 0.000 \\ AI & 0.73 a & 0.55 b & 0.46 c & 0.38 d & 0.02 & 0.000 \\ TI & 1.22 a & 0.80 b & 0.62 c & 0.50 d & 0.05 & 0.000 \\ \hline \end{tabular} a, b, c, d: different letters in the same row indicate significant differences during storage according to Tukey’s HSD test; values are expressed as means. AI: atherogenic index; TI: thrombogenic index.  
\end{table}
Table 5: Fatty acid profile (g/100 g FAMEs) of raw Merino lamb burgers with different amounts of pecans in their formulation.