# Removal of Volatile Phenols From Wine Using Crosslinked Cyclodextrin Polymers
## 2 Results and Discussion
### Reusability Test  
Following treatment, the CD polymers were recovered and washed with methanol, before being added to fresh wine samples to determine their reusability. However, no significant differences were found between the RPA for residual volatile phenols across four cycles of adsorption (Figure 5). As mentioned above, the mechanism of CD encapsulation is mainly based on non-covalent bond hydrophobic interactions. The process can, therefore, be reversed by placing the CD polymers in a more hydrophobic environment, enabling them to be regenerated for repeated use. \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & & \multicolumn{2}{c}{**Guaiacol**} & \multicolumn{2}{c}{**4-methylguaiacol**} & \multicolumn{2}{c}{**4-ethylguaiacol**} & \multicolumn{2}{c}{**4-ethylphenol**} \\ \hline control & & 2.34 a \(\pm\) 0.03 & & 2.18 a \(\pm\) 0.04 & & 1.89 a \(\pm\) 0.03 & & 0.97 a \(\pm\) 0.03 & \\  & 1\% \(w/v\) & 2.07 b \(\pm\) 0.03 & 89\% & 1.96 a \(\pm\) 0.01 & 90\% & 1.63 b \(\pm\) 0.01 & 86\% & 0.81 b \(\pm\) 0.01 & 84\% \\ \(\beta\)-CD-HDI & 2\% \(w/v\) & 1.69 c \(\pm\) 0.05 & 72\% & 1.57 b \(\pm\) 0.03 & 72\% & 1.25 c \(\pm\) 0.02 & 66\% & 0.55 c \(\pm\) 0.01 & 57\% \\  & 5\% \(w/v\) & 1.29 d \(\pm\) 0.05 & 55\% & 1.17 c \(\pm\) 0.05 & 55\% & 0.82 d \(\pm\) 0.02 & 43\% & 0.23 d \(\pm\) 0.01 & 23\% \\  & 1\% \(w/v\) & 1.97 b \(\pm\) 0.06 & 84\% & 1.90 a \(\pm\) 0.05 & 87\% & 1.63 b \(\pm\) 0.05 & 86\% & 0.83 ab \(\pm\) 0.04 & 86\% \\ \(\gamma\)-CD-HDI & 2\% \(w/v\) & 1.61 c \(\pm\) 0.10 & 69\% & 1.50 b \(\pm\) 0.10 & 69\% & 1.31 c \(\pm\) 0.00 & 69\% & 0.64 c \(\pm\) 0.00 & 66\% \\  & 5\% \(w/v\) & 1.27 d \(\pm\) 0.04 & 54\% & 1.11 c \(\pm\) 0.10 & 51\% & 0.88 d \(\pm\) 0.08 & 46\% & 0.36 d \(\pm\) 0.06 & 37\% \\ \hline \multicolumn{8}{c}{Values are means of three replicates \(\pm\) standard error (and percentage of control). Values followed by different} \\ \multicolumn{8}{c}{letters are significantly different (one-way ANOVA, \(p=0.05\)).} \\ \end{tabular}
\end{table} 
Table 2: Residual volatile phenols levels (as relative peak area) following addition of \(\beta\)-CD-HDI and \(\gamma\)-CD-HDI to red wine spiked with volatile phenols. \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & & \multicolumn{2}{c}{**Guaiacol**} & \multicolumn{2}{c}{**4-methylguaiacol**} & \multicolumn{2}{c}{**4-ethylguaiacol**} & \multicolumn{2}{c}{**4-ethylphenol**} \\ \hline control & & 2.43 a \(\pm\) 0.06 & & 2.30 a \(\pm\) 0.09 & & 1.99 a \(\pm\) 0.08 & & 1.04 a \(\pm\) 0.05 & \\  & 5 g/L & 2.06 bc \(\pm\) 0.02 & 85\% & 1.88 b \(\pm\) 0.07 & 82\% & 1.62 b \(\pm\) 0.07 & 81\% & 0.79 b \(\pm\) 0.01 & 76\% \\ \(\beta\)-CD & 10 g/L & 1.96 bc \(\pm\) 0.02 & 81\% & 1.80 b \(\pm\) 0.07 & 78\% & 1.38 bc \(\pm\) 0.07 & 69\% & 0.49 c \(\pm\) 0.01 & 47\% \\  & 20 g/L & 1.87 d \(\pm\) 0.01 & 77\% & 1.73 bc \(\pm\) 0.02 & 75\% & 1.15 c \(\pm\) 0.03 & 58\% & 0.33 c \(\pm\) 0.00 & 32\% \\  & 5 g/L & 2.19 b \(\pm\) 0.06 & 90\% & 1.97 ab \(\pm\) 0.06 & 85\% & 1.64 b \(\pm\) 0.05 & 82\% & 0.89 ab \(\pm\) 0.03 & 86\% \\ \(\gamma\)-CD & 10 g/L & 1.83 cd \(\pm\) 0.08 & 75\% & 1.68 bc \(\pm\) 0.10 & 73\% & 1.41 bc \(\pm\) 0.09 & 71\% & 0.76 b \(\pm\) 0.07 & 73\% \\  & 20 g/L & 1.61 d \(\pm\) 0.05 & 66\% & 1.45 c \(\pm\) 0.10 & 63\% & 1.13 c \(\pm\) 0.04 & 57\% & 0.49 c \(\pm\) 0.01 & 48\% \\ \hline \multicolumn{8}{c}{Values are means of three replicates \(\pm\) standard error (and percentage of control). Values followed by different} \\ \multicolumn{8}{c}{letters are significantly different (one-way ANOVA, \(p=0.05\)).} \\ \end{tabular}
\end{table} 
Table 3: Residual volatile phenols levels (as relative peak area) following addition of \(\beta\)-CD and \(\gamma\)-CD to red wine spiked with volatile phenols. Figure 4: \({}^{1}\)H 2D ROESY NMR (600 MHz, pD 3.5 and 25 \({}^{\circ}\)C) spectrum of deuterated model wine containing \(\beta\)-CD and (**a**) guaiaicol, (**b**) 4-methylguaiaicol and (**c**) 4-ethylguaiaicol.