## 3 Results and Discussion
### Antioxidant Activity and Polyphenolic Composition  
To better portray the effect of HP-\(\beta\)-CD on polyphenol extraction from PP, the extracts obtained under optimized conditions, at 30 \({}^{\circ}\)C, were tested for antioxidant activity. The results were compared with extracts prepared using 60% aqueous ethanol, a commonly used green solvent, and 60% aqueous methanol, a common conventional solvent (Table 3).  
Figure 4: The effect of temperature on total polyphenol yield (Y\({}_{\text{TP}}\)), under optimized extraction conditions. Asterisk (*) denotes statistically different value (\(p<0.05\)). All other values showed no statistical difference.  
Extraction with HP-\(\beta\)-CD afforded almost by 19% higher YTP compared to 60% EtOH and by 21% compared to 60% MeOH, while differences in both AAR and PR were marginal and non-significant (\(p>0.05\)). This outcome clearly suggested that extraction of PP with HP-\(\beta\)-CD was virtually as effective as with common organic solvents. The HP-\(\beta\)-CD extract was then analyzed with HPLC to identify the major polyphenic constituents. Of the trace recorded at 325 nm (Figure 5), four phytochemicals could be tentatively identified, namely neochlorogenic acid, chlorogenic acid, caffeic acid and ferulic acid.  
The results from the quantitative analysis are given in Table 4. The most abundant polyphenol was ferulic acid, followed by caffeic and chlorogenic acid, whereas neochlorogenic acid occurred at much lower levels. Unlike previous reports, chlorogenic and caffeic acids were not the predominant constituents. In fact, chlorogenic acid content (83.67 \(\upmu\)g g\({}^{-1}\) dm) was significantly low compared to 4100 \(\upmu\)g g\({}^{-1}\) dm reported by other studies [18]. Yet, other authors determined levels ranging from 2.16 to 267.4 \(\upmu\)g g\({}^{-1}\) dm [15] and from 299.51 to 904.21 \(\upmu\)g g\({}^{-1}\) dm [41].  
Regarding caffeic acid, the content determined was comparable to 68.19-129.05 \(\upmu\)g g\({}^{-1}\) dm found in earlier investigations [15]. However, a yield of 592 \(\upmu\)g g\({}^{-1}\) dm has been achieved for PP extraction with pressurized liquids [19], but yields varying from 160 to as high as 1220 \(\upmu\)g g\({}^{-1}\) dm have been attained with ethanol/water mixtures and ultrasound-assisted extraction [18]. Other authors reported  
\begin{table}
\begin{tabular}{c c c} \hline
**Peak \#** & **Polyphenol** & **Content (\(\upmu\)g g\({}^{-1}\) dm) \(\pm\) sd** \\ \hline
1 & Neochlorogenic acid & 28.95 \(\pm\) 1.60 \\
2 & Chlorogenic acid & 83.67 \(\pm\) 0.54 \\
3 & Caffeic acid & 88.98 \(\pm\) 0.28 \\
4 & Ferulic acid & 108.73 \(\pm\) 3.52 \\  & \(Sum\) & 310.34 \\ \hline \end{tabular}
\end{table}
Table 4: Contents of the major polyphenols detected in PP extracts.  
Figure 5: Chromatogram of PP extract obtained with HP-\(\beta\)-CD, under optimized conditions, at 30 \({}^{\circ}\)C. The trace was recorded at 325 nm. Peak assignment: 1, neochlorogenic acid; 2, chlorogenic acid; 3, caffeic acid; 4, ferulic acid.  
\begin{table}
\begin{tabular}{c c c c} \hline
**Extraction** & **YTP (mg CGAE g\({}^{-1}\) dm)** & **AAR (\(\upmu\)mol DPPH g\({}^{-1}\) dm)** & **PR (\(\upmu\)mol AAE g\({}^{-1}\) dm)** \\ \hline HP-\(\beta\)-CD & 16.86 \(\pm\) 1.75 & 16.37 \(\pm\) 0.49 & 8.83 \(\pm\) 0.09 \\
60\% EtOH & 13.67 \(\pm\) 0.27 & 25.26 \(\pm\) 0.76 & 9.47 \(\pm\) 0.09 \\
60\% MeOH & 13.27 \(\pm\) 1.01 & 23.04 \(\pm\) 0.69 & 11.49 \(\pm\) 0.11 \\ \hline \end{tabular}
\end{table}
Table 3: Comparison of the characteristics of the extract obtained with HP-\(\beta\)-CD with those of common conventional solvents. Values reported are means \(\pm\) standard deviation.  
values of 250 to 324 ug g\({}^{-1}\) dm [41]. On the other hand, ferulic acid was shown to occur at levels of 1 to 28 ug g\({}^{-1}\) dm [42].