## 3 Results and Discussion
### Antioxidant Phenolic Compounds in Blackcurrants  
Since the antioxidant capacities showed a consistent reduction trend, we compared the specific phenolics of blackcurrant fruit extracts with [PERSON]'s methods [50]. The results (Figure 5) indicated differences between day 0 (d0) and day 20 (d20) under each pretreatment, and the distinct differences were observed in 1 h treated blackcurrants. Under 1 h pretreatment, the value of most compounds (d1-1 h) was higher than the values after storage (d20-1 h). Meanwhile, 2 h of UVC pretreatment before and after storage had lower values of each compound than other pretreated blackcurrants, since the color of the compounds was lighter in the heatmap. This indicated that extended UVC pretreatment (more than 1 h) negatively affected the preservation of specific phenolic compounds in blackcurrants, even though storage did not influence the total amounts as determined by colorimetric assays (Table 2). \begin{table}
\begin{tabular}{c c c c c} \hline
**Storage Duration** & **Total Phenolics (\(\upmu\)g** & **DPPH (TEAC** & **FRAP (Fe\({}^{2+}\)** & **Ascorbic Acids** \\
**(Days)** & **GAE/mL)** & **mM/mg)** & **Equivalent nmol/mg)** & **(mg/100 g)** \\ \hline
0 & 520.33 \(\pm\) 30.19 \({}^{\text{a}}\) & 4.14 \(\pm\) 0.08 \({}^{\text{a}}\) & 321.87 \(\pm\) 34.40 \({}^{\text{a}}\) & 90.87 \(\pm\) 13.54 \({}^{\text{b}}\) \\
5 & 518.69 \(\pm\) 52.33 \({}^{\text{a}}\) & 4.07 \(\pm\) 0.15 \({}^{\text{a}}\) & 246.79 \(\pm\) 47.55 \({}^{\text{b}}\) & 82.13 \(\pm\) 3.99 \({}^{\text{c}}\) \\
10 & 524.09 \(\pm\) 87.43 \({}^{\text{a}}\) & 4.10 \(\pm\) 0.14 \({}^{\text{a}}\) & 243.10 \(\pm\) 39.70 \({}^{\text{b}}\) & 92.39 \(\pm\) 9.64 \({}^{\text{ab}}\) \\
15 & 474.98 \(\pm\) 37.81 \({}^{\text{ab}}\) & 3.91 \(\pm\) 0.10 \({}^{\text{b}}\) & 187.40 \(\pm\) 38.98 \({}^{\text{ab}}\) & 98.81 \(\pm\) 4.35 \({}^{\text{a}}\) \\
20 & 454.71 \(\pm\) 61.64 \({}^{\text{b}}\) & 3.97 \(\pm\) 0.07 \({}^{\text{b}}\) & 215.10 \(\pm\) 25.78 \({}^{\text{c}}\) & 94.95 \(\pm\) 6.52 \({}^{\text{ab}}\) \\ F-value & 2.74 & 8.88 & 24.64 & 5.46 \\ \(p\)-Value & 0.058 & 0.00032 *** & 2.712 \(\times\) 10\({}^{-7}\)*** & 0.004 ** \\ \hline \end{tabular}  
* Means followed by the same letter within columns are not significantly different for each character of blackcurrants. Values are the mean \(\pm\) standard deviation of the replicates. \(p\)-value significance (\(p\) < 0.01 **, or \(p\) < 0.001 ***) indicates the statistically significant across the storage periods. The F-value indicates that the difference in the group means (sampling days) is substantially greater than the variability within each group (day).  
\end{table} 
Table 3: Blackcurrant total phenolic and antioxidant capacity changes during storage. There were no massive changes between the most antioxidant phenolic compounds before and after storage (Figure 6). Four large compounds (>1000 ng/g) were detected: cyanidin, epigallocatechin, catechin, and epicatechin. Cyanidin in blackcurrants without treatment (0 h) had the most considerable amounts, with 31,788.1 ng/g before storage and 29,692.4 ng/g after storage. Interestingly, UVC had a substantial influence on cyanidin quantities, as the amount of cyanidin in the treatments decreased from approximately 30,000 ng/g without UVC pretreatment (0 h) to 10,000 to 18,000 ng/g under 1 h and 2 h UVC pretreatments. Cyanidin and its glycosides belong to anthocyanins and are responsible for the bright colors of fruits and flowers [51]. It has been reported that this pigment can be degraded by UV light, which breaks the cyanidin molecule [52]. The amount of degradation was observed even with half an hour of UVC pretreatment in this study. Meanwhile, it has been noticeable that approximately 10.6% more cyanidin was detected in the 0.5 h UVC sample on day 20 compared to the 0.5 h pretreated blackcurrants before storage (d0-0.5 h). Some studies have indicated that different exposure durations and intensities of UVC can trigger varying mechanisms in fruits, which further impact fruit quality and shelf life [53].