## 3 Results and Discussion
### Evaluation of Oxidative Stress Markers and Antioxidant Content in Melatonin-Treated Dried Apricots  
Our study elucidated the intricate biochemical responses of dried apricots to exogenous melatonin application, focusing on oxidative stress markers and antioxidant content. Our findings indicated a nuanced interplay between melatonin concentration and various physiological parameters, offering valuable insights into post-harvest fruit preservation strategies. The results demonstrated that exogenous melatonin application significantly influences oxidative stress markers and antioxidant content in dried apricots, with higher concentrations (100 \(\upmu\)M and 1000 \(\upmu\)M) effectively mitigating lipid peroxidation and hydrogen peroxide accumulation while modulating \(\beta\)-carotene levels. In our results, malondialdehydehyde (MDA) and hydrogen peroxide (H\({}_{2}\)O\({}_{2}\)) levels, key indicators of oxidative stress, exhibited significant reductions in apricots treated with higher concentrations of melatonin (100 \(\upmu\)M and 1000 \(\upmu\)M) compared to the control and low-dose (10 \(\upmu\)M) treatments (Table 2). The 100 \(\upmu\)M melatonin treatment resulted in the lowest MDA accumulation (16.55 \(\upmu\)mol/L) and significantly reduced H\({}_{2}\)O\({}_{2}\) levels (0.76 \(\upmu\)mol/g), demonstrating its efficacy in mitigating oxidative damage. This observation aligns with the findings of [PERSON] et al. [33], who reported lower MDA and H\({}_{2}\)O\({}_{2}\) accumulation in melatonin-treated white mulberry fruits. The decrease in these oxidative stress markers suggests that melatonin effectively mitigates lipid peroxidation and cellular damage, corroborating its role as a potent antioxidant [34; 35]. The concentration-dependent effect of melatonin on oxidative stress markers underscores the importance of dosage optimization in post-harvest treatments. \begin{table}
\begin{tabular}{l c c c} \hline
**Treatments** & **L*** & **a*** & **b*** \\ \hline Control & 26.91 \(\pm\) 0.77 \({}^{\text{b}}\) & 4.98 \(\pm\) 0.76 \({}^{\text{c}}\) & 9.44 \(\pm\) 0.97 \({}^{\text{b}}\) \\
10 \(\upmu\)M-MT & 27.40 \(\pm\) 0.79 \({}^{\text{ab}}\) & 5.55 \(\pm\) 0.60 \({}^{\text{bc}}\) & 10.15 \(\pm\) 0.76 \({}^{\text{ab}}\) \\
100 \(\upmu\)M-MT & 28.74 \(\pm\) 0.47 \({}^{\text{a}}\) & 6.67 \(\pm\) 0.13 \({}^{\text{a}}\) & 11.33 \(\pm\) 0.26 \({}^{\text{a}}\) \\
1000 \(\upmu\)M-MT & 28.84 \(\pm\) 1.30 \({}^{\text{a}}\) & 6.35 \(\pm\) 0.60 \({}^{\text{ab}}\) & 11.15 \(\pm\) 1.04 \({}^{\text{a}}\) \\ \hline \end{tabular}  
* MT: Melatonin. Each data point represents the average of three replicates (mean \(\pm\) standard error). Letters in the same column indicate differences at the significance level of \(p<\) 0.05.  
\end{table} 
Table 1: The effect of exogenous melatonin application on the L*, a*, and b* values of sun-dried apricots. Intriguingly, melatoninin was undetectable in all treatment groups post-drying (Table 2), an outcome that may be attributed to the molecule's susceptibility to degradation under the harsh conditions of sun-drying, including heat and light exposure. As [PERSON] et al. [15] noted, the short half-life of melatonin and limited information on its persistence in fruit tissues support our observations. This finding underscores the need for further research into melatonin stability and alternative application methods in fruit preservation. The rapid degradation of melatonin during processing raises questions about the duration of its protective effects and the potential for developing more stable formulations or application techniques to prolong its efficacy throughout the drying process. On the other hand, the \(\beta\)-carotene content exhibited significant variation among treatments, with the 100 uM melatonin application yielding the highest content (223.07 mg/kg) as shown in Table 2. This result surpasses the range reported by [PERSON] et al. [36] for the Hachaliloglu dried apricot variety (30.00-33.30 mg/100 g), suggesting a potential protective effect of melatonin on carotenoid preservation.