## 3 Results and Discussion
### Antioxidant Activity of Maca Extracts
The comparison of the antioxidant potential expressed as the RSA (%) for extracts obtained in various conditions using 96% ethanol as a solvent is presented in Figure 1, while using water is in Figure 2. It was found that RSA values for ethanolic extracts varied from 7.4% in the case of the 15-min maceration (E 15 M) to 49.7% for the 15-min reflux extraction (E 15 RE). The application of water as the solvent was definitively more effective and resulted in RSA values of 48.7% for the 15 min maceration (W 15 M) to 74.8% for the 60-min maceration with shaking (W 60 MSH), which was the best result obtained among all studied process conditions. Both in the case of water and ethanol extraction, for the M, MSH, and UAE techniques, the highest values of the antioxidant potential were found for the longest extraction time (60 min), while for the RE technique, RSA slightly decreased with the prolongation of the extraction time. The observed differences among various extraction times were not statistically significant (FDR > 0.05). Since the majority of studied isolation processes showed the best results were obtained for 60 min of extraction, all the results obtained for this time variant using DPPH radical scavenging activity method are compared in Figure 3.  
The presented graph clearly shows that after 60 min for all extraction techniques, radical scavenging was significantly higher for water extracts than for ethanolic extracts obtained in the same conditions (\(p\) < 0.05). Performing the statistical analysis of all results for 60-min processes, it was proved that the ethanolic extract with the highest antioxidant potential was obtained by the reflux extraction (RE), while for water extraction, the best results were obtained by the maceration with shaking (MSH) technique. Importantly, in both cases, the differences in the antioxidant potential of extracts obtained in the best conditions and obtained by using the other techniques were statistically significant (\(p\) < 0.05). Figure 1: Influence of extraction technique and conditions on DPPH radical scavenging activity of maca extracts obtained using 96% ethanol as the solvent (M—maceration; MSH—maceration with shaking; UAE—ultrasound-assisted extraction; RE—reflux extraction). Moreover, a correlation analysis between the two applied methods, DPPH and Folin-Ciocalteu, was also carried out. For water extracts, it was found that there were statistically significant positive correlations between phenolic compounds content and antioxidant potential for M, MSH, and UAE techniques (r = 0.950; r = 0.800, and r = 0.766, respectively). In the case of alcoholic extracts, the situation was analogous--the relationships between the antioxidant potential and the content of phenolic compounds were high and significant for the M, MSH, and UAE techniques (r = 0.900; r = 0.866, and r = 0.945, respectively). Figure 3: Comparison of RSA values for maca extracts obtained in 60-min extraction processes using 96% ethanol and water as the solvent (M—maceration; MSH—maceration with shaking; UAE—ultrasound-assisted extraction; RE—reflux extraction); * statistically significant differences among the results obtained using two different solvents at \(p\) < 0.05. Figure 2: Influence of extraction technique and conditions on DPPH radical scavenging activity of maca extracts obtained using water as the solvent (M—maceration; MSH—maceration with shaking; UAE—ultrasound-assisted extraction; RE—reflux extraction). respectively). Such relationships were not found for reflux extraction (RE). The reason may be the possible degradation processes of some active compounds at the higher temperature during the prolonged water extraction, resulting in the observed trends in the decreasing of the total phenolic content and DPPH radical scavenging activity values, which was not observable for the extraction using ethanol. This fact needs further studies for a detailed explanation. Studies reported in the literature so far indicate that maca contains several antioxidant compounds.