## 3 Results and Discussion
### Effects of Proportion of Pecan nuts on pH, Water-Holding Capacity and Instrumental Colour  
The addition of pecan nuts caused a significant increase in the pH (\(p<0.001\)) and WHC (\(p<0.05\)) of lamb burgers (Table 2). Ayo, Carballo, Solas and Jimenez-Colmenero [42] reported an increase in the pH values of meat batters with the addition of walnuts. However, Corfades, Ayo, Serrano, Carballo, and Jimenez-Colmenero [43] reported that increasing the amount of walnuts used while keeping the meat protein content constant did not have a significant effect on the pH of the meat batters. Likewise, Ayo et al. [34] found that the incorporation of walnuts did not have an impact on the pH of the frankfurters.  
Moreover, the increase in the pH values in burgers enhanced with pecan nuts may be related to the increase in WHC, since an increase in the pH causes an increase in the pH of the meat due to changes in the electrical charges of the muscle proteins [44]. In addition, the formulation of the burgers affected the colour coordinates (Table 2). Pecan nuts increased the lightness and CIE b* values (\(p<0.001\)) of raw burgers. According to Perez Alvarez et al. [45], this could be due to the fact that the fat and oil in the pecan nuts provide a shine to the hamburgers. As for the CIE b* values, their increase may be due to the colour of the nut itself--usually yellowish--which would cause a progressive change in colour as the amount of pecan nuts increases in the hamburger. These results are in  
\begin{table}
\begin{tabular}{c c c c c c c} \hline  & \multirow{2}{*}{**Control**} & \multicolumn{4}{c}{**With Pecan**} & \multirow{2}{*}{**SEM**} & \multirow{2}{*}{**\(p\)-Value**} \\ \cline{3-3} \cline{5-6}  & & **5\%** & & **10\%** & & **15\%** \\ \hline Protein content & 16.74 & 17.46 & 17.63 & 16.63 & 0.20 & 0.178 \\ Fat content & 13.98 c & 14.94 bc & 15.71 b & 18.27 a & 0.34 & 0.000 \\ Moisture & 62.25 a & 59.10 ab & 57.08 bc & 53.43 c & 0.74 & 0.000 \\ Ash content & 4.34 a & 3.24 b & 3.61 b & 3.29 b & 0.10 & 0.000 \\ Total phenol content & 0.82 c & 1.17 b & 1.49 a & 1.54 a & 0.06 & 0.000 \\ Calories (kcal/g DM) & 14.66 a & 13.98 ab & 13.76 bc & 13.28 c & 0.16 & 0.002 \\ \hline \end{tabular} a, b, c: different letters in the same row indicate significant differences during storage according to Tukey’s HSD test; values are expressed as means; SEM: standard error of the mean; total phenol content is expressed as g of gallic acid (GAE)/kg DM.  
\end{table}
Table 1: Nutritional composition of Merino lamb burgers with different amounts of pecans in their formulation.  
line with the results obtained by Serrano Agullo [46] in his study on the production of potentially functional restructured beef through the addition of walnuts. In contrast, CIE a* values decrease (\(p<0.001\)) with the addition of pecan nuts in the formulation. According to Florowski et al. [47], this could be due to the fact that the incorporation of different amounts of walnuts, with their yellow colour, reduces the red tone of the burger meat. As with other types of enriched burgers, it is important to take into account the modifications in the colour of the burgers, given the importance that colour has for consumers [4].