## 3 Results
Finally, the aging time did not affect the sulphur compounds (\(p>0.05\)). The effect of aging time in TBARs, hydroperoxides, protein carbonyls, superoxide dismutase, catalase, and glutathione peroxidase values of donkey meat steaks aged for 14 days under vacuum conditions are reported in Table 5. TBARs values at nine and 14 aging days are higher than those \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & & & & & & & \\ \hline
**Volatile Compound** & _m/z_ & **LRI** & **1** & **3** & **6** & **9** & **14** & **SEM** & _p-Value_ \\ \hline Cyclobutanol & 44 & 504 & 143.69 & 169.85 & 147.22 & 138.39 & 143.89 & 4.76 & 0.957 \\
1-Pentanol & 55 & 847 & 2755.10 & 2733.92 & 1463.86 & 2160.24 & 1930.46 & 3.98 & 0.547 \\
1-Hexanol & 56 & 959 & 2130.13 & 2067.04 & 2218.5 & 1341.74 & 2341.82 & 1.12 & 0.729 \\
1-Hepanol & 70 & 1046 & 365.67 & 248.69 & 59.14 & 116.04 & 92.70 & 680.64 & 0.160 \\
1-Octen-3 ol & 57 & 1051 & 1418.47 & 1662.70 & 841.05 & 1001.59 & 1393.13 & 14.12 & 0.121 \\ n-Tidecan-1-ol & 55 & 1073 & 182.45 & 247.07 & 242.18 & 225.81 & 244.91 & 274.05 & 0.771 \\
1-Hepanol, 2-diethyl- & 69 & 1085 & 1333.83 & 129.36 & 230.15 & 146.55 & 137.41 & 2488.83 & 0.601 \\
1-Decanol & 70 & 1027 & 21.60 & 25.42 & 34.15 & 26.52 & 20.61 & 427.0 & 0.488 \\
1-Tetradecanol & 68 & 1225 & 25.66 & 28.03 & 33.32 & 28.62 & 22.28 & 118.82 & 0.764 \\
1-Decanol, 2-hexyl- & 97 & 1241 & 21.03 & 22.45 & 28.21 & 24.67 & 16.65 & 16.25 & 0.491 \\
1-Butanol, 2-methyl- & 57 & 1243 & 18.14 & 16.15 & 19.77 & 17.15 & 17.39 & 22.01 & 0.943 \\ Total Alcohols & & 7655.53 & 634.587 & 3301.09 & 5243.44 & 4372.90 & 822.52 & 0.237 \\ \hline Butanoic acid & 60 & 918 & 45.42 & 70.17 & 57.60 & 83.42 & 106.55 & 1.994 & 0.336 \\ Hexanoic acid & 60 & 1088 & 73.60 & 83.20 & 70.53 & 49.83 & 102.80 & 1.357 & 0.172 \\ Formica did, cycl ester & 56 & 1133 & 47.48 & 110.11 & 92.78 & 122.76 & 108.28 & 1.44 & 0.282 \\ Total Carboxylic Acids & & 1698.2  & 217.63  & 208.69  & 219.33  & 317.62  & 207.10 & 0.003 \\ \hline Diazeem, dimethyl- & 15 & 532 & 213.87 & 202.38 & 140.26 & 237.28 & 245.35 & 9.366 & 0.487 \\ Pyrazine, methyl- & 94 & 893 & 79.65  & 57.10  & 100.68  & 163.72  & 165.78  & 0.019 \\
2-Propen-1 amine & 56 & 916 & 46.69 & 105.47  & 137.19 & 78.33  & 59.53  & 10.758  & 0.523  \\ Pyrazine, 2,5-dimethyl- & 42 & 982 & 223.78  & 168.44  & 227.77  & 45.65  & 14.637  & 14.637  & 0.009 \\ Pyrazine, trimethyl- & 122 & 1064 & 128.90  & 93.50  & 154.74  & 277.12  & 293.64  & 19.326  & -0.001 \\ Total Nitrogen Compound & & 606.07  & 626.90  & 810.43  & 1232.10  & 1633.13  & 11.795 & 0.004 \\ \hline Dimethylsulfide & 62 & 534 & 26.63 & 21.63 & 15.03 & 24.71 & 17.47 & 17.208 & 0.558 \\ Carbonosulfide & 76 & 533 & 119.65 & 117.40 & 94.24 & 132.27 & 133.34 & 33.188 & 0.540 \\ Total Sulfur Compound & & 136.65 & 146.63 & 123.96 & 144.38 & 157.85 & 16.872 & 0.761 \\ \hline \multicolumn{7}{c}{Different letters in the same line show statistical differences (a\({}^{\text{b.b.}}\): \(p<0.01\)). SEM: standard error of mean; _m/z_:} \\ \multicolumn{7}{c}{Quantififier ion; LRI: Lineal Retention Index calculated for DB-624 capillary column (J&W) \(\times\) 0.25 mm} \\ \multicolumn{7}{c}{id, 1.4 μm film thickness) installed on a gas chromatograph equipped with a mass selective detector. LRI: linear retention index in agreement with literature for the same chromatographic column [25; 34; 43].} \\ \end{tabular}
\end{table} 
Table 4: Effect of aging time in the alcohols, carboxylic acids, nitrogen compounds, and sulphur compounds content, expressed as quantifier area units (AU \(\times\) 10\({}^{3}\)/g), of donkey meat steaks aged for 14 days under vacuum conditions (\(n=10\) samples for each aging time). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & & & & & & & & & & \\ \hline
**Volatile Compound** & _m/z_ & **LRI** & **1** & **3** & **6** & **9** & **14** & **SEM** & _p-Value_ \\ \hline
**Volatile Compound** & _m/z_ & **LRI** & **1** & **3** & **6** & **9** & **14** & **SEM** & _pobserved at three aging days (\(p<0.01\)).