## 3 Results and Discussions
### Antioxidant Activity and Bioactive Compounds  
The results presented in Table 2 reveal a noteworthy contrast in antioxidant activity between freeze-dried aronia and aronia pomace. Freeze-dried aronia exhibited significantly higher antioxidant activity, registering a value of 10,621.67 \(\pm\) 0.28 \(\upmu\)M Trolox/100 g of dry weight, marking a substantial 61% increase. In comparison, aronia pomace recorded a value of 4140.1 \(\pm\) 0.18 \(\upmu\)M Trolox/100 g of fresh weight. Notably, findings from a study by [PERSON] et al. [30] reported a Trolox equivalent of 2.95 \(\upmu\)mol/g for aronia powder, highlighting its elevated antioxidant activity. This significant difference in antioxidant activity can be attributed to the freeze-drying process, known for its ability to concentrate antioxidant compounds in aronia. Therefore, freeze-dried aronia can be considered a notably potent source of antioxidants compared to aronia pomace [30]. The concentration of antioxidant compounds in freeze-dried aronia indicates its potential to be a more concentrated and bioactive source, affirming its superiority over aronia pomace in terms of antioxidant potential, along with the impact of processing techniques on the antioxidant content of aronia-derived products.  
Table 3 highlights a substantial contrast in total phenolic compounds between aronia pomace and freeze-dried aronia. Aronia pomace exhibited a concentration of 16,792.24 \(\pm\) 3.78 \(\upmu\)g/g, while freeze-dried aronia demonstrated a significantly higher content of 44,373.46 \(\pm\) 3.21 \(\upmu\)g/g, marking a notable 164.45% increase. This augmented total phenolic content is complemented by a 60% rise in anthocyanins, a 75% increase in flavonoids, and a 65% elevation in acids for freeze-dried aronia.  
\begin{table}
\begin{tabular}{c c c} \hline Freeze-dried aronia & 10,621.67 \(\pm\) 0.28 \(\upmu\)M Trolox/100 g dry weight \\ \hline Fresh aronia & 4140.1 \(\pm\) 0.18 \(\upmu\)M Trolox/100 g fresh weight \\ \hline \end{tabular}
\end{table}
Table 2: Antioxidant activity of extracts before and after freeze-drying.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Peak** & **Rt (min)** & **UV** & **[M + H]\({}^{+}\) (\(\upmu\)/z)** & **Compounds** & **Fresh Aronia \({}^{\text{B}}\)** & **Freeze-Dried Aronia \({}^{\text{B}}\)** \\ \hline
1 & 3.04 & 270 & 139 & Hydroxybenzoic acid & 9198.83 \(\pm\) 0.28 & 22,880.942 \(\pm\) 1.20 *** \\
2 & 10.32 & 530, 280 & 611 & Cyanidin diglucoside & 3751.54 \(\pm\) 0.35 & 9411.872 \(\pm\) 0.27 *** \\
3 & 11.29 & 530, 280 & 465 & Cyanidin glucoside & 1203.94 \(\pm\) 0.21 & 3010.610 \(\pm\) 0.29 *** \\
4 & 13.05 & 529, 280 & 449 & Cyanidin & 124.38 \(\pm\) 0.09 & 308.464 \(\pm\) 0.10 *** \\
5 & 13.35 & 322 & 287 & Caffeic acid & 200.33 \(\pm\) 0.11 & 764.026 \(\pm\) 0.11 *** \\
6 & 14.48 & 356, 256 & 181 & Kaempferdiglucoside & 266.31 \(\pm\) 0.10 & 978.302 \(\pm\) 0.11 *** \\ \hline \end{tabular}
\end{table}
Table 3: The quantity of phenolic compounds in aronia samples (\(\upmu\)g/g of sample).  
In line with our findings, [PERSON] et al. [30] underscored the exceptional value of aronia powder, attributing it to a rich composition of bioactive compounds, including high levels of total polyphenols, as well as vitamins C and E. Their study highlighted the antioxidant activity of the powder derived from _A. melanogaster_ pomace [30], emphasizing the intricate biochemical composition contributing to its noteworthy properties. The amplified presence of total phenolic compounds, along with anthocyanins, flavonoids, and acids in freeze-dried aronia, further positions it as a potent source of bioactive compounds with potential health benefits. This insight adds depth to our understanding of the nutritional composition of freeze-dried aronia, supporting its consideration as a valuable ingredient in functional foods and nutraceuticalals.