## 4 Conclusions  
Our work showed that wheat straw could represent a low-cost alternative for production of fermentable sugars and xylo-oligosaccharides with low DP. Among the treatments applied, alkaline and enzymatic treatment with xylanase showed better results in terms of sugar release (glucose, xylose and arabinose) (18 g/L sugars), while XOS were generally released in lower amounts (highest concentration of 1.33 g/L). Refining experiments were carried out to obtain a purified fraction for potential food applications by using anion and \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Parameters**} & \multicolumn{4}{c}{**Resins**} \\ \hline \multirow{2}{*}{**Parameter**} & **Hydrolysate D Severity Factor 3.53** & \multirow{2}{*}{**MN502**} & **AC** & **A103S** & **C150S** \\ \hline \multirow{2}{*}{\begin{tabular}{c} HMF \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{9.71 \(\pm\) 0.02} & \multirow{2}{*}{0.50 \(\pm\) 0.01} & \multirow{2}{*}{\(<\)0.004} & \multirow{2}{*}{0.71 \(\pm\) 0.01} & \multirow{2}{*}{0.65 \(\pm\) 0.01} \\ \hline \multirow{2}{*}{\begin{tabular}{c} Furfural \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{139 \(\pm\) 0.3} & \multirow{2}{*}{2.31 \(\pm\) 0.1} & \multirow{2}{*}{\(<\)0.0124} & \multirow{2}{*}{\(<\)0.0124} & \multirow{2}{*}{5.37 \(\pm\) 0.1} \\ \hline \multirow{2}{*}{\begin{tabular}{c} Phenol \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{16.66 \(\pm\) 0.02} & \multirow{2}{*}{\(<\)0.079} & \multirow{2}{*}{\(<\)0.079} & \multirow{2}{*}{\(<\)0.079} & \multirow{2}{*}{16.20 \(\pm\) 0.01} \\ \hline \multirow{2}{*}{\begin{tabular}{c} Kresol \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{\(<\)0.058} & \multirow{2}{*}{\(<\)0.058} & \multirow{2}{*}{\(<\)0.058} & \multirow{2}{*}{\(<\)0.058} & \multirow{2}{*}{\(<\)0.058} \\ \hline \multirow{2}{*}{\
\begin{tabular}{c} Catechol \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{\(<\)0.027} & \multirow{2}{*}{\(<\)0.027} & \multirow{2}{*}{\(<\)0.027} & \multirow{2}{*}{\(<\)0.027} & \multirow{2}{*}{\(<\)0.027} \\ \hline \multirow{2}{*}{
\begin{tabular}{c} Guajc \\ (mg/L) \\ \end{tabular} } & \multirow{2}{*}{3.81 \(\pm\) 0.01} & \multirow{2}{*}{\(<\)0.008} & \multirow{2}{*}{\(<\)0.008} & \multirow{2}{*}{\(<\)0.008} & \multirow{2}{*}{\(<\)0.008} \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Removal of furfural, HMF and phenols after the down-streaming process. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{2}{c}{**Parameters**} & \multicolumn{4}{c}{**Resins**} \\ \hline \multirow{3}{*}{\ \begin{tabular}{c} Xylose (g/L) \\ \end{tabular}  } & \multicolumn{2}{c}{Hydrolysate D severity factor (log R\({}_{0}\) = 3.53)} & MN-502 & AC & A103S & C150S \\ \cline{2-5}  & 9.47 \(\pm\) 0.01 NS (0.992) & 1.31 \(\pm\) 0.01 NS (1.00) & 0.09 \(\pm\) 0.01 * & 1.29 \(\pm\) 0.00 ** & 1.28 \(\pm\) 0.00 ** \\ \hline \multirow{2}{*}{ \begin{tabular}{c} Arabinose \\ (g/L) \\ \end{tabular}  } & \multirow{2}{*}{1.54 \(\pm\) 0.64 ** & 0.78 \(\pm\) 0.05 NS (1.00)} & 0.79 \(\pm\) 0.05 ** & 0.18 \(\pm\) 0.00 NS (0.05) & 0.05 \(\pm\) 0.00 NS (0.05) \\ \hline \multicolumn{2}{c}{Monosaccharides} & \multirow{2}{*}{81.01} & \multirow{2}{*}{92.0} & \multirow{2}{*}{86.64} & \multirow{2}{*}{87.92} \\ removal (\%) & & & & & \\ \hline \multicolumn{2}{c}{XOS (g/L)} & \multirow{2}{*}{1.33 \(\pm\) 0.13 NS (0.721)} & \multirow{2}{*}{1.31 \(\pm\) 0.06 NS} & \multirow{2}{*}{1.26 \(\pm\) 0.03 NS} & \multirow{2}{*}{1.19 \(\pm\) 0.04 NS} & \multirow{2}{*}{1.1 \(\pm\) 0.01 NS} \\ \hline \multicolumn{2}{c}{Acetic acid} & \multirow{2}{*}{1.76 \(\pm\) 0.05 ** & 0.27 \(\pm\) 0.01 NS (1.00)} & 0.2 \(\pm\) 0.01 NS (1.00) & 0.18 \(\pm\) 0.01 NS (1.00) & 0.35 \(\pm\) 0.01 NS (0.05) \\ \cline{2-5}  & & & & & \\ \hline \multicolumn{2}{c}{PO\({}_{4}\)\({}^{3}\)\(-\)P} & \multirow{2}{*}{58.58 \(\pm\) 0.50 ** & 16.34 \(\pm\) 1.23 ** & 23.73 \(\pm\) 1.79 ** & 1.36 \(\pm\) 0.01 ** & 11.09 \(\pm\) 0.83 ** \\ \hline \multicolumn{2}{c}{SO\({}_{4}\)\({}^{2}\)\({}^{2}\)\({}\)\({}^{2}\)\({}\)\({}^{2}\)\({}  
cation exchange chromatography.