## 3 Results and Discussion
### DPPH Radical Scavenging Activity
#### 3.3.3. Association Between the Phenolic Compound Content and BCSO Antioxidant Capacity  
As reported in other research, BCSO contains a large amount of phenolic compounds [32; 49]. It is known that phenols have a considerable effect on the oxidative stability of oils and, in many works of research, were assayed as the primary antioxidants in oils [40], although the content of minor compounds such as tocopherols can also impact the oxidation process of oils [50]. In our work, the change in phenol content was monitored spectroscopically based on the synchronous fluorescence spectra (SFS), which can be used to assess the presence of bioactive compounds in oils [22; 51]. The total SFS of diluted BCSO (1%, \(v/v\), in \(n\)-hexane), where the fluorescence intensity is presented as the wavelength interval (\(\Delta\lambda\))/excitation wavelength relation (Figure 5b), reflects the most intense fluorescence for \(\Delta\lambda\) = 20-50 nm in the excitation region of 280-320 nm. The main fluorescence excitation maximum at 293 nm acquired at \(\Delta\lambda\) = 30 nm exhibits an additional band with a low intensity on the short-wavelength side. The better resolved fluorescence bands exhibited SFS obtained at an 10 nm wavelength interval, where two separate bands at 272 nm and 300 nm were noted, similar to virgin olive oil [21]. The first one can be assigned to phenols, whereas the second is attributed to tocopherols [21; 52; 53]. For the longer \(\Delta\lambda\), behind the main maximum (\(\Delta\lambda\) = 50 nm), an asymmetric fluorescence band with a maximum at about 285 nm was assigned, which may result from the overlap of the characteristic bands of both groups of compounds [21]. The short-wavelength band observed for \(\Delta\lambda\) = 10 nm, referring to  
Figure 5: (**a**) The calculated IC50 for BCSO samples; (**b**) the total synchronous fluorescence spectra (SFS) of diluted BCSO (1%, \(v/v\), in n-hexane); and (**c**) the change in fluorescence intensity at 272 nm (\(\Delta\lambda\) = 10 nm) for both BSCO open and closed samples. different phenols, was used to evaluate the total phenolic content in BCSO during the accelerated storage test in our study. The intensity of this band decreased considerably with the heating time, along with maintaining the difference in the rate of change of this parameter between the \"open\" and \"closed\" samples (Figure 5c). Although the resistance and stability of antioxidants in different edible oils to thermal oxidation are highly variable [54], our results indicate the significant degradation of phenols in BSCO upon heating, especially in the presence of oxygen, similar to that observed for virgin olive oil [55]. On the other hand, antioxidant activity is known to have a linear correlation with the phenolic contents [5]. The first stage of the obtained relations presented in Figure 5a demonstrates this tendency. Moreover, statistically significant linear correlations were found between IC50 and the maximum fluorescence intensity of band appears at \(\Delta\lambda\) = 10 nm, with a correlation coefficient \(r=-0.8000\) and \(-0.9300\) for the open and closed samples of BSCO, respectively. The observed linear trend, together with the strong correlation found, indicates the significant participation of phenolic compounds in the observed antioxidant properties of BCSO. A positive correlation between the amount of total phenols and BCSO oxidative stability was found in [49]. Nevertheless, it is not always possible to associate a high content of phenolic compounds with strong oxidative stability or antioxidant properties [26; 38], since different phenolic compounds can differently affect the oxidative stability of the oil [40]. Moreover, in our study, disturbances in the linear trend of IC50 were visible in the ending stage of thermal oxidation, although linearity was maintained until the end of the experiment for the phenol content.