## 3 Results and Discussion
Under conditions of room temperature, the fruits of plants with saline stress had the lowest values of antioxidant capacity during the three evaluations. The T0 showed the highest values at the time of harvest and at eight days of storage. At 15 days, the fruits of the plants with application of Cu NPs were those with higher antioxidant capacity, followed by the T0. These results suggest that the stress caused by the application of NaCl negatively affects the antioxidant DPPH ability, when the fruits are kept at room temperature (24 \({}^{\circ}\)C). This may be because the plants suffered a high stress by the constant application of NaCl, which triggered an oxidative burst [9], resulting in the reduction of antioxidant compounds. Under refrigeration conditions, the T0 had the highest antioxidant capacity at 8 and 15 days of storage. At eight days, the fruits of the plants with application of NaCl presented the lowest value. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Storage** & **Treatment** & **0 ds** & **8 ds** & **15 ds** & **23 ds** \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Room \\ temperature \\ \end{tabular} } & NPs Cu & 2.09 \(\pm\) 0.02 a & 1.93 \(\pm\) 0.01 f & 2.09 \(\pm\) 0.01 a & not done \\  & NaCl & 2.07 \(\pm\) 0.01 b & 1.75 \(\pm\) 0.01 h & 1.85 \(\pm\) 0.02 e & not done \\  & NPs Cu + NaCl & 2.09 \(\pm\) 0.02 a & 1.87 \(\pm\) 0.02 g & 1.63 \(\pm\) 0.02 f & not done \\  & T0 & 2.09 \(\pm\) 0.01 a & 2.09 \(\pm\) 0.01 b & 2.01 \(\pm\) 0.01 b & not done \\ \hline \multirow{4}{*}{Refrigeration} & NPs Cu & not done & 2.03 \(\pm\) 0.01 d & 1.92 \(\pm\) 0.01 c & 2.14 \(\pm\) 0.03 a \\  & NaCl & not done & 1.98 \(\pm\) 0.01 e & 1.91 \(\pm\) 0.01 cd & 2.12 \(\pm\) 0.02 a \\  & NPs Cu + NaCl & not done & 2.05 \(\pm\) 0.01 c & 1.89 \(\pm\) 0.01 d & 2.11 \(\pm\) 0.02 a \\  & T0 & not done & 2.12 \(\pm\) 0.01 a & 2.04 \(\pm\) 0.01 b & 2.13 \(\pm\) 0.01 a \\ \hline \hline \end{tabular}  
* ds: days of storage. NPs Cu: plants without stress and with application Cu nanoparticles to 250 mg L\({}^{-1}\). NaCl: plants with stress by NaCl. NPs Cu + NaCl: plants with stress by NaCl and with application Cu nanoparticles at 250 mg L\({}^{-1}\). T0: absolute control without application of Cu nanoparticles and without stress by NaCl. Each value is expressed as mean \(\pm\) standard deviation (\(n=3\)). Different letters by column indicate statistical differences between treatments according to [PERSON]’s least significant difference test (\(p\leq 0.05\)).  
\end{table} 
Table 6: 2,2\({}^{\prime}\)-diphenyl-1-picrylhydrazyl (DPPH) antioxidant capacity (\(\upmu\)M Trolox equivalents per gram of fresh weight) in tomato fruits at different storage times at room temperature (24 \(\pm\) 1 \({}^{\circ}\)C) and refrigeration (4 \(\pm\) 1 \({}^{\circ}\)C and relative humidity at 80%). At 15 days, the lowest antioxidant capacity was observed in the fruits of the plants with application of Cu NPs and NaCl. On the other hand, in the antioxidant capacity by ABTS differences between treatments were presented in all evaluations. At the time of harvest, the T0 had the highest antioxidant capacity. In this case, the fruits of the plants of the two treatments that included the application of NaCl had lower antioxidant capacity. At eight days of storage at room temperature, the fruits of plants with saline stress had the lowest values of antioxidant capacity. In this case, the fruits of the plants with application of Cu NPs presented the highest value of antioxidant capacity. Under refrigeration conditions, the opposite was observed, this treatment had the lowest antioxidant capacity. The T0 in this case presented the highest value of antioxidant capacity. At 15 days, storage at room temperature, the results were consistent with that observed in previous evaluations. The fruits of the plants with saline stress had the lowest values of antioxidant capacity. In this condition, the fruits of the T0 plants obtained the best results, followed by the fruits of the plants with application of Cu NPs.