## 3 Results and Discussion
### Characteristics of Phytochemical  
The total content of polyphenols in the control carrot juice ranged from 11.18 mg/100 mL to 13.46 mg/100 mL. The sumac powder supplementation clearly increased the content of these bioactive compounds in the juice. Sumac fruits are rich sources of polyphenols [59; 60]; hence, they can be an attractive additive for the enrichment of juices with these pro-health ingredients. The total content of polyphenols in the cold plasma-treated carrot juice (P) was only slightly lower than that in the control sample. The greatest difference (2.24 mg/100 mL) was noted after 72 h, but it was not statistically significant. The effect of cold plasma on the content of polyphenols is not clear-cut. Their amount may decrease due to the degradation process accompanying the exposure of the product to reactive radicals released during plasma generation. In turn, the action of charged particles and UV radiation may result in a more intense rupture of raw material tissues as well as the disintegration and disruption of cell membranes, which facilitates the extraction of phenolic compounds [61]. This dual effect of cold plasma treatment was evidenced by the present results. The cold plasma treatment of carrot juice supplemented with 0.5% of sumac contributed to an increase in the total content of polyphenols, whereas a decline in the content was observed in juice samples enriched with 3% of the additive (Table 5). Carotenoids are important components of all orange/red fruits and vegetables, as they are responsible for the attractive color and pro-health properties. Some of these natural antioxidants are used for the synthesis of vitamin A in the human organism. Therefore, the content of carotenoids should be taken into account while processing carotenoid-rich raw materials. The total content of carotenoids in the analyzed carrot juices ranged from 11.13 mg/100 g to 18.90 mg/100 g. After 24 h, it was observed that the 3% addition of sumac powder resulted in a 15% increase in the content of these pigments. After 24 h, it was observed that the 3% addition of sumac powder increased the content of these pigments by 2.41 mg/100 g. In turn, the cold plasma treatment of carrot juice samples resulted in a significant decrease in the content of carotenoids compared to the untreated samples (by 0.74 mg/100 g in the sample without added sumac and by 0.65 mg/100 g in the variant with the 3% addition) (Table 5).  
As shown in the other studies of the effect of cold plasma on juices, the content of carotenoids increased in some cases. The use of a dielectric barrier discharge (DBD) plasma reactor at a voltage of 70 kV for 4 min allowed an increase in the amount of carotenoids in carrot juice compared to the control sample [47]. Also, cold plasma treatment carried out using the laboratory PE-100 plasma system (with nitrogen as the process gas) using an electric field with a frequency of 80 kHz resulted in an increase in the content of these compounds in acerola juice. The greatest increase in carotenoids was observed at a gas flow rate of 10 mL/min and a treatment duration of 10 min [62]. The increase in the content of these bioactive compounds through the action of cold plasma can be explained by the increased extraction thereof from the juice matrix. The bioavailability of some compounds in cold plasma-treated juices may be increased as a result of cell disruption as well as the dissociation of aggregates and association of bioactive substances with the cell wall [61]. During the storage of the carrot juices, the greatest losses in the total content of carotenoids were detected in the control sample. After 72 h, their content was approximately 30% lower than in the juice analyzed after 24 h.