## 3 Results and Discussion
### Antioxidant Activity of Maca Extracts
Similar relationships were found in the alcoholic extract; in the M, MSH, and UAE methods, the relationships were positive and statistically significant (r = 0.948 for M and UAE and r = 0.895 for MSH). The exception was the RE technique, where a small negative but statistically insignificant correlation was found. Analyzing the results of total phenolic contents, some similarities can be seen between the observed trends compared to DPPH radical scavenging activity. The extraction of phenolic compounds was also significantly more effective using water than ethanol. TPC values obtained for ethanolic extracts varied from 3.2 mg GAE/L (E 15 M) to 95.3 mg GAE/L (E 60 RE). Using ethanol as a solvent, the best technique for the isolation of phenolic compounds was reflux extraction (RE). Regardless of the technique used, the highest phenolics content was found after 60 min extraction. The application of water as the solvent resulted in a significantly higher content of phenolic compounds; even for the 15-min maceration, the result was 73.2 mg GAE/L (W 15 M), while the prolongation of maceration to 60 min gave the result of 111.2 mg GAE/L, being higher than the best result obtained in 60-min reflux extraction with ethanol. Isolation of phenolic compounds using water was effectively enhanced by shaking, application of ultrasounds, and higher temperature. The best result of 136.9 mg GAE/L was obtained in the 60-min ultrasound-assisted extraction (W 60 UAE) process, but it is worth noticing that maceration with shaking (MSH) was also very effective. In the case of the RE method, the extraction time had an adverse effect because the content of polyphenols slightly decreased. An in-depth analysis of the correlation between the extraction time and the content of phenolic compounds showed statistically significant positive correlations for water extraction by using M, UAE (r = 0.948), and MSH (r = 0.843) techniques, which indicates that the prolongation of extraction resulted in higher content of phenolic compounds. In the case of alcoholic extracts, significant positive correlations were found between the extraction time and the content of phenolic compounds (r = 0.948 for M, MSH, RE, and r = 0.952 for UAE). Generally, in most cases, the prolongation of the extraction time, especially to 60 min, positively influenced DPPH scavenging activity and the amount of extracted phenolic compounds, but this trend was not observed in reflux extraction (RE), maybe due to \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Variables** & **Minimum** & **Maximum** & **Mean** & **Standard** & **Median** & **Lower** & **Upper** \\
**(n = 72)** & & & & & & & **Quartile** & **Quartile** \\ \hline RSA [\%] & 6.94 & 75.32 & 47.45 & 21.04 & 50.00 & 29.29 & 66.50 \\ TEAC [uM TE/L] & 14.96 & 231.16 & 143.06 & 66.53 & 151.11 & 85.62 & 203.28 \\ TPC [mg GAE/L] & 2.09 & 138.45 & 82.73 & 44.67 & 86.41 & 42.77 & 126.41 \\ \hline \hline \end{tabular} RSA—Radical Scavenging Activity; TEAC—Trolox Equivalents Antioxidant Capacity, TPC—Total Phenolic Content, GAE—Gallic Acid Equivalents.  
\end{table} 
Table 2: Descriptive statistics of the tested variables. possible decomposition processes of active compounds at higher temperatures. Nevertheless, statistical analysis of the differences among the results indicated that regardless of the extraction technique, the obtained values of both radical scavenging activity and total phenolic content in various extraction times were not statistically significant (FDR > 0.05). For better illustration and proper interpretation of the obtained results, the graphical visualization of the influence of maca extraction conditions on DPPH radical scavenging activity was carried out.