## 3 Results and Discussion
### Evaluation of Oxidative Stress Markers and Antioxidant Content in Melatonin-Treated Dried Apricots
The consistently elevated CUPRAC values across treatments indicate a substantial presence of flavonoid compounds, emphasizing the importance of employing multiple analytical methods for comprehensive antioxidant capacity assessment. The antioxidant compounds play a crucial role in protecting biomolecules, such as proteins and lipids, from oxidative damage by delaying their oxidation, as reported by [PERSON] et al. [50]. Melatonin's dual hydrophilic and lipophilic properties contribute to its effectiveness as a post-harvest preservation agent for fruits and vegetables [33]. The compound's ability to facilitate reactions with alkyl peroxide and hydroxyl free radicals demonstrates its versatility in antioxidant mechanisms. It is, however, crucial to acknowledge that the spectrophotometric methods employed for TPC determination are not entirely specific and may detect various easily oxidizable compounds under analysis conditions [44]. This limitation underscores the need for more specific analytical approaches in future research to better understand the precise mechanisms of melatonin's antioxidant effects. The formation of new compounds during radical scavenging, as observed by [PERSON] [48], suggests the need for more sophisticated analytical techniques to track these transformations. These findings have significant implications for the fruit processing industry. While our results demonstrate promising outcomes with melatonin treatment, it is essential to critically examine the statistical significance of our findings across different concentrations. The observed variations in sugar composition and antioxidant capacity reveal a complex, non-linear relationship between melatonin concentration and the fruit quality parameters. Although we highlighted the 100 uM concentration as particularly effective for sugar preservation, the statistical similarities between 100 uM and 1000 uM treatments for several parameters warrant careful interpretation. The lack of statistically significant differences in total phenolic content (TPC), DPPH, and CUPRAC antioxidant capacity measurements between these concentrations suggests that higher melatonin doses may not consistently translate to proportional improvements in fruit quality (Table 4). This observation underscores the importance of precise dosage optimization and highlights the need for nuanced approaches to post-harvest fruit treatments. Future research should focus on more granular concentration ranges and employ advanced statistical techniques to elucidate the most effective melatonin application strategies, potentially revealing subtle mechanisms that our current analytical methods might not fully capture. Also, the observed patterns in both sugar composition and antioxidant capacity suggest that melatonin treatment protocols may need to be tailored to specific quality objectives. The safety and non-toxic nature of melatonin makes it a particularly attractive option for commercial applications in the fruit supply chain. However, the complex relationship between treatment concentration and the various quality parameters necessitates careful consideration when developing treatment protocols. \begin{table}
\begin{tabular}{l c c c} \hline \hline \multirow{2}{*}{**Treatments**} & **TPC** & **DPPH** & **CUPRAC** \\  & **(mg GAE/100 g)** & **(mg TE/100 g)** & **(mg TE/100 g)** \\ \hline Control & 243.68 \(\pm\) 14.02 a & 100.13 \(\pm\) 10.01 ab & 634.72 \(\pm\) 26.98 a \\
10 uM-MT & 243.52 \(\pm\) 5.68 a & 111.30 \(\pm\) 11.13 a & 542.13 \(\pm\) 8.10 b \\
100 uM-MT & 201.20 \(\pm\) 19.59 b & 86.48 \(\pm\) 7.75 b & 489.76 \(\pm\) 26.67 c \\
1000 uM-MT & 207.71 \(\pm\) 16.85 b & 90.34 \(\pm\) 9.03 ab & 510.30 \(\pm\) 29.13 b \\ \hline \hline \end{tabular}  
* MT: Melatonin. Each value represents the mean of three replicates (mean \(\pm\) standard error). Letters indicate differences at \(p<\) 0.05 significance level.  
\end{table} 
Table 4: Total phenolic and antioxidant capacities of dried aprico s after exogenous melatonin application.