## 3 Results and Discussion  
### Biological Activity of Fruit Extracts and lyophilistes  
In the first part of our investigation, the antioxidant and antibacterial activity of fruit extracts obtained through extraction with acidified ethanol (80%) assisted by ultrasound from frozen and dried fruits (described in Section 2.1.2), and freeze-dried fruits obtained through freeze-drying of non-extracted fruit material were determined. The TPC and antioxidant activity of extracts and lyophilistes are presented in Table 1. The results showed that the polyphenol content, as well as the antioxidant activity, were higher in extractscompared to freeze-dried fruits. Significant differences in these parameters between individual fruits were also observed. Considering the TPC value and antioxidant activity, the obtained results for the tested fruit may be ranked in decreasing order as follows: black chokeberry > blueberry > hawthorn > red currant > sea buckthorn > quince. It is worth underlining that the antioxidant capacity of black chokeberry extracts and lyophilates is significantly higher than those of the other fruits, while differences between other fruits are not always so clear. Extracts and freeze-dried blueberry and hawthorn demonstrated a similar antioxidant activity, although they significantly differed in the polyphenol content. Similarly, extracts from quince and sea buckthorn exhibited comparable activities while the polyphenol content was different, whereas the lyophilates obtained from these fruits did not differ in terms of phenolic compound amount and antioxidant activity. The obtained results are in line with the literature data. The berries such as black chokeberry, blueberry, and red currant are some of the richest sources of polyphenol compounds [26; 27; 28; 29; 30; 31]. Chokeberry is an abundant source of phenolic compounds, including procyanifs, anthocyanins, phenolic acids, and their analogues with a relatively high content of the major bioactive components of Aronia berries, from 10 mg to 5500 mg per 100 g of the dried fruits. Polyphenol compounds determine not only the biological activity of chokeberry but also influence the interest in this fruit as a therapeutic agent [32; 33; 34]. A high amount of anthocyanins is also found in other dark berries such as blueberry along with other flavonoids including procyanifs, catechin, and epicatechin, as well flavonols (quercetin, kaempfer, myricetin) and nonflavonoid compounds such as phenolic acids or stilbenes [35; 36; 37]. Similarly, hawthorn is known for its antioxidant properties due to the presence of polyphenols such as epicatechin, chlorogenic acid, and hyperoside [38]. Also, quince is a good source of antioxidants including flavonoids, phenolic acids, quercetin, rutin, or kaempfer, which makes it useful in various applications including functional food product design [39; 40; 41; 42]. The sea buckthorn used in the presented study is an interesting plant, contains a high level of carotenoids, acts mainly as an antioxidant, but also influences its potential to reduce the risk of some diseases such as cancers and eye diseases [43]. Moreover, it contains different flavonoids and polyphenolic acids [44]. It is worth underlining that the comparison of different fruits in terms of their composition and biological activity can significantly vary depending on geographical factors, climate conditions, as well as variety [45]. Therefore, the content of TPC as well as the antioxidant properties of extracts described in the literature vary due to different methods of their preparation and even part of the plant used for extraction. [PERSON] [46], by working on the optimal extraction conditions, obtained a total average TPC concentration in aronia extract at a level of 38.057 mg/g, quite similar to that of the presented work. [PERSON] et al. [47] used the ultrasound-assisted extraction of phenolic compounds from blueberry p