## 3 Results and Discussion
### Effect of Thermal Processing on the Antioxidant Capacity of Broccoli Extracts
\begin{table}
\begin{tabular}{l c c c c c c c c} \hline  & **BO** & **BOW** & **BL** & **BLW** & **ST** & **STW** & **AF** & **PF** \\ \hline ABTS (\% & & & & & & & & \\ inhibition) & 26.73 \(\pm\) 8.01 c & 57.57 \(\pm\) 18.22 a & 20.04 \(\pm\) 7.34 c & 21.90 \(\pm\) 14.97 c & 50.17 \(\pm\) 12.05 ab & 20.71 \(\pm\) 14.84 c & 43.04 \(\pm\) 9.92 b & 27.41 \(\pm\) 21.59 c \\ DPPH (\% & & & & & & & & \\ inhibition) & 27.14 \(\pm\) 10.43 ab & 18.26 \(\pm\) 12.52 bc & 15.51 \(\pm\) 9.68 c & 10.71 \(\pm\) 8.06 cd & 35.48 \(\pm\) 2.28 a & 4.38 \(\pm\) 3.74 d & 36.12 \(\pm\) 15.71a & 17.54 \(\pm\) 2.74 bc \\ FRAP (\% & & & & & & & & \\ reduction) & 47.79 \(\pm\) 6.34 d & 79.34 \(\pm\) 3.28 a & 48.33 \(\pm\) 10.49 d & 35.37 \(\pm\) 8.86 e & 73.87 \(\pm\) 3.46 ab & 14.59 \(\pm\) 8.30 f & 67.79 \(\pm\) 8.71 b & 56.22 \(\pm\) 8.63 c \\ \hline  & & & & & & & & \\  & & & & & & & & \\ \end{tabular} Values represent average \(\pm\) standard deviation of three biological and four technical replicates. Different letters indicate a significant difference among the values in a row (one-way ANOVA, Duncan’s test, \(p\)\(\leq\) 0.05). BO = broccoli boiled; BOW = water after boiling broccoli; BL = broccoli blanched; BLW = water after blanching broccoli; ST = broccoli steamed; STW = water after steaming broccoli; AF = broccoli air-fried; PF = broccoli blanched and then pan-fried.  
\end{table} 
Table 3: Effect of different thermal processing techniques on antioxidant capacity of broccoli extracts. high antioxidant potential of steamed broccoli and water remaining after cooking could be due to the high content of total phenols and other groups of polyphenols (Table 1), which act as antioxidants. In addition to the high content of polyphenols (Table 1), the high levels of glucosinolates (Figure 2) and carotenoids (Table 2) also contributed to the high antioxidant potential of air-fried broccoli. These results suggest that, from the point of view of antioxidant potential, steaming and air-frying are optimal ways of preparing broccoli for consumption. The main purpose of heat treatment is to ensure microbial safety by eliminating pathogens and to simultaneously alter or improve the health-promoting properties of the food [81]. Thermal processes disrupt the structural integrity of cell walls, thereby promoting the release of bioactive compounds such as polyphenols [82]. Thermal processing resulted in different abilities of broccoli to preserve the plasmid DNA structure (Figure 4). The water remaining after boiling and blanching of broccoli were most effective in preserving the supercoiled DNA form (99.51% and 94.81%, respectively). This suggests that bioactive phytochemicals leached into cooking water by heat processing show high biological activity with relevance to genome protection. Polyphenolics, including flavonoids, are hydrophilic components that are able to leach out from the tissues into the water, which exert a certain level of stability when exposed to high temperatures [57]. Therefore, it is likely that these compounds have contributed to the DNA preservation from oxidative stress. Moreover, it was shown that hydrophilic compounds have markedly higher antioxidant potential than lipophilic [83], which further confirms the best protective effect of the remaining water. Additionally, the DNA-protective activity of the cooking water (BOW and BLW) suggests that the disruption of plant tissue facilitates the release of bioactive compounds into the water, illustrating how structural breakdown influences their availability. This is the first time that the DNA-protecting activity of cooking water, a common cooking byproduct rich in bioactive compounds normally disposed of, is highlighted, emphasizing its possibility for valorization in functional food or nutraceutical purposes. Cooked, blanched, steamed, and pan-fried extracts showed similar levels, among each other, of the preservation of the supercoiled DNA form. Water from steamed broccoli was the least effective in preserving the supercoiled DNA form (32.17%).