## 3 Results and Discussion
### Antioxidant Characteristics  
The antioxidant properties of the PBS films modified with the chloroform extract and sea buckthorn scCO\({}_{2}\) extract are shown in Table 5. The unmodified PBS showed poor \begin{table}
\begin{tabular}{c c c c c c} \hline
**Sample** & **L*** & **a*** & **b*** & **\(\Delta\)E** & **YI** & **Opacity** \\ \hline PBS & 64.40 \(\pm\) 0.33 c & 14.49 \(\pm\) 0.14 b & 39.27 \(\pm\) 0.47 b & 0.0 & 87.12 \(\pm\) 0.96 a & 14.26 \(\pm\) 0.73 b \\ PBS-Ch 0.01 & 63.82 \(\pm\) 0.18 a & 14.65 \(\pm\) 0.13 a & 40.16 \(\pm\) 0.56 a & 1.12 \(\pm\) 0.48 a & 89.89 \(\pm\) 1.32 c & 12.04 \(\pm\) 1.52 a \\ PBS-Ch 0.05 & 64.75 \(\pm\) 0.08 d & 14.62 \(\pm\) 0.06 a & 40.17 \(\pm\) 0.47 a & 1.01 \(\pm\) 0.39 a & 88.62 \(\pm\) 1.11 b & 15.70 \(\pm\) 2.32 c \\ PBS-CO\({}_{2}\) 0.01 & 63.90 \(\pm\) 0.34 a & 14.87 \(\pm\) 0.02 c & 41.22 \(\pm\) 0.32 d & 2.05 \(\pm\) 0.39 b & 92.15 \(\pm\) 1.18 d & 13.73 \(\pm\) 3.01 a \\ PBS-CO\({}_{2}\) 0.05 & 61.94 \(\pm\) 0.10 b & 16.11 \(\pm\) 0.03 d & 46.68 \(\pm\) 0.26 d & 7.97 \(\pm\) 0.25 c & 107.67 \(\pm\) 0.65 e & 18.80 \(\pm\) 1.56 d \\ \hline \end{tabular} Values are presented as the mean \(\pm\) standard deviation. Means with different lowercases are significantly different at \(p\) < 0.05.  
\end{table} 
Table 4: Color (L*, a*, b*), total color difference (\(\Delta\)E), yellowish index (YI), and opacity of unmodified and modified PBS films. properties for scavenging DPPH free radicals (1.74 \(\pm\) 1.92%). This finding has already been established for PBS and has been demonstrated previously [12; 16]. The addition of chloroform and scCO\({}_{2}\) sea buckthorn extracts increased the antioxidant properties of the films. The addition of 0.01 g extract per 1 g of PBS resulted in similar improvements in these properties, to 19.55 \(\pm\) 2.07% and 15.60 \(\pm\) 2.91% for scCO\({}_{2}\) and chloroform extracts, respectively. Increasing the additive amount resulted in even more significant antioxidant properties within the PBS films, which reached 41.13 \(\pm\) 1.31% for films modified with scCO\({}_{2}\) extract and 26.44 \(\pm\) 3.01% for films modified with chloroform extract. Thus, in the case of films modified with 0.05 g of extracts per 1 g of PBS, a significant increase in antioxidant properties was achieved, and the sea buckthorn scCO\({}_{2}\) extract showed outstanding effects. These results were confirmed by researchers [30], who reported that sea buckthorn extracts containing a high amount of phenolics (such as glycosides isorhamnetin and quercetin, with small amounts of triterpenes) had strong antioxidant activity, while the activity of the non-polar extract was lower, but still evident. The authors assumed that alterations in the profile of active compounds in the sea buckthorn extract may have contributed to the differences in the case of their antioxidant activity. It is worth mentioning that the activity of the non-polar extract indicates that the triterpenoids that were identified also possess antioxidant potential. These results are also in line with those obtained for sea buckthorn leaf extracts in combination with chitosan, where a significant improvement in antioxidant properties was observed with an increase in the amount of extract [20], and sea buckthorn leaf extracts were used to modify PVA films; the stronger the antioxidant properties, the greater the proportion of applied extract [22]. Interestingly, in a study of apple slices coated with CMC modified with sea buckthorn leaf extract, it was found that in the tested range (from 0.5% to 2% \(w/w\) extract), the strongest antioxidant properties over 10 days of storage were exhibited by a coating with 1.5% extract [24], with a similar effect also being observed for chitosan coatings with sea buckthorn leaf extract [21]. [PERSON] et al. tested extracts based on various parts of the sea buckthorn plant (seed, root, leaves, stem) and the strongest antioxidant properties were identified in extracts from the root and seeds.