## 3 Results and Discussion
These findings showing L* changes toward a lighter color are in agreement with reports from the previous studies. However, previous studies also observed that different treatments may delay the color change in vegetables and fruits [64; 65; 66]. For example, [PERSON] and co-workers report that the treatment of persimmon leaves by ozone microbubble treatment had relatively little effect on leaf quality characteristics [35]. However, we observed that ozone treatment had no statistically significant effects on the a* value. It is known that the green color increases as the a* value moves to the negative (\(-\)) direction. In our experiments, we observed a tendency for the color to turn lighter green. The unfavorable result in terms of maintenance of green color following treatment with ozone in comparison to the control samples may be attributed to its oxidizing properties. Other studies report that green crops became discolored or oxidized after ozonation at higher doses [33]. In our study, no statistically significant effects were observed in a* values after the ozone treatment of 30 g of parsley. The increase in b* values in the positive (+) direction indicates increased yellow color. The higher values of b* values in green vegetables can be explained by the degradation of chlorophyll with aging [67]. We observed a statistically significant increase in b* values only in the sample of 30 g of parsley ozonated with 1.5 mg O\({}_{3}\) L\(-\)1 and an increase in b* values in the samples of 10 g and 25 g of parsley ozonated with 1.5 O\({}_{3}\) mg/L and also in the sample of ozonated water in a closed circuit (Table 3). The effects of the ozone treatment on \(\Delta\)E* values showed that ozone changed the color of the parsley. Higher doses of ozone resulted in more visible color changes. The changes were more visible (\(\Delta\)E > 2) when we used 1.5 O\({}_{3}\) mg/L (\(\Delta\)E = 5.8-6.2). However, there were no differences in \(\Delta\)E depending on the parsley mass, and the \(\Delta\)E changes were not statistically significant compared to the control sample (Table 3). In the decontamination process, both obtaining the appropriate microbiological purity and maintaining the product's usable properties are expected. The sensory evaluation of parsley depends on the chemical composition of the essential oil and the superficial layer. Therefore, the chemical composition of parsley essential oils and volatile organic compounds in the headspace of plant material before and after the ozonation process were evaluated. The tests presented in Table 4 indicate that the raw material did not undergo any change during decontamination. The major compounds found in parsley leaves are 1,5,8-p-methatriene and \(\beta\)-phellandrene. These compounds are considered to make a major contribution to the sensory properties of parsley. Other compounds in parsley leaves include myristicin, \(\alpha\)-p-dimethylstyrene, \(\beta\)-myrcene, and apiole. In some cases, \(\alpha\)- and \(\beta\)-pinene are also found [5]. In the present study, 1,5,8-p-methatriene (2-26%), \(\beta\)-phellandrene (1.6-12%), and myristicin (0.4-15%) were detected in the parsley leaves. The climate conditions, plant species, growth stage, plant tissue, and date of sowing strongly affect the essential oil content of parsley leaves [5]. Aromatic plants may be used either fresh or dried, depending on the purpose. During different processes, such as drying and freezing, several changes occur, depending on