## Appendix A
\begin{table}
\begin{tabular}{l l l} \hline \hline
**Classification** & **Biopolymers** & **Description** \\ \hline \multicolumn{3}{l}{Medium-grained sand} \\ \hline \hline \multirow{3}{*}{Solid crusts} & Polysaccharides: & 1 and 2 wt\% (XG = 0.25 and 0.50 wt\%) concentrations. \\  & CS, CMC, WS, XG Proteins: & Crusts were recoverable in a single piece or up to four fully recoverable pieces. \\  & FBPC, TG & 1 wt\% concentration. Crusts broke into multiple large pieces, whereby some pieces were only partially recoverable and crumbled into countless pieces. \\  & PBS, POS & 2 wt\% concentration. Crusts were almost fully recoverable in several pieces. \\  & PP, WP, WPC & 1 wt\% concentration. Crusts were very weak and \\  & NLS & brittle, crumbling into countless unrecoverable pieces. \\  & Proteins: & 2 wt\% concentration. Crusts had increased stability but \\  & HEA, HG & were still extremely fragile. \\ \hline \multicolumn{3}{l}{Fine-grained silica sand} \\ \hline \multirow{3}{*}{Solid crusts} & Polysaccharides: & 1 and 2 wt\% (XG = 0.25 and 0.50 wt\%) concentrations. \\  & CS, CMC, PES, XG & Crusts were recoverable in a single piece or up to four fully recoverable pieces. \\ \hline \multirow{3}{*}{Mediocre crusts} & Polysaccharides: & 1 and 2 wt\% concentrations. Crusts were thick and \\  & NLS, POS & almost fully recoverable in a few pieces at both tested \\  & Proteins: & concentrations. (TG exhibited a unique characteristic, \\  & FBPC, HEA, HG, \\  & PP, TG, WP, WPC & \\ \hline \multirow{3}{*}{Ductile crusts} & Polysaccharides: & 1 and 2 wt\% concentrations. Crusts were very thin and \\  & WP & ductile and even curled up during the curing period. \\ \hline \end{tabular}
\end{table} 
Table 6: Qualitative classification of biopolymers according to their crust’s visual appearance (cf. Figures 10 and 11). \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Crust Thickness (mm)**} \\ \hline \hline  & \multicolumn{3}{c}{**Medium-Grained Sand**} & \multicolumn{3}{c}{**Fine-Grained Silica Sand**} \\ \hline \hline  & **1 wt\%** & **2 wt\%** & **1 wt\%** & **2 wt\%** \\ \cline{2-8}  & **M** & **SD** & **M** & **SD** & **M** & **SD** \\ \hline \multicolumn{8}{l}{Polysaccharides} \\ \hline \hline \multicolumn{8}{l}{Carboxymethyl cellulose} & 6.3 & 1.6 & 7.1 & 0.4 & 9.6 & 0.5 & 9.3 & 0.2 \\ \multicolumn{8}{l}{Corn starch} & 7.5 & 0.3 & 5.9 & 0.8 & 7.7 & 0.5 & 7.3 & 1.0 \\ \multicolumn{8}{l}{Sodium lignocellulosic} & 2.4 & 1.0 & 4.6 & 0.9 & 13.1 & 0.3 & 18.1 & 2.7 \\ \multicolumn{8}{l}{Pea starch} & 6.3 & 0.2 & 6.9 & 0.4 & 8.3 & 0.6 & 7.0 & 0.2 \\ \multicolumn{8}{l}{Potato starch} & 3.4 & 0.5 & 7.3 & 0.2 & 11.7 & 0.4 & 13.7 & 0.2 \\ \multicolumn{8}{l}{Wheat starch} & 6.3 & 0.4 & 4.7 & 1.6 & 3.2 & 1.3 & 2.4 & 0.5 \\ \multicolumn{8}{l}{Xanthan gum} & 6.6 & 0.1 & 5.9 & 0.1 & 7.3 & 0.4 & 5.8 & 0.3 \\ \hline \multicolumn{8}{l}{Average} & 5.5 & 1.8 & 6.1 & 1.0 & 8.7 & 3.0 & 9.1 & 4.9 \\ \hline \multicolumn{8}{l}{Proteins} \\ \hline \hline \multicolumn{8}{l}{Fava bean protein concentrate} & 7.6 & 0.4 & 8.8 & 0.1 & 11.6 & 0.4 & 11.0 & 2.1 \\ \multicolumn{8}{l}{Hen egg albumen} & 0.4 & 0.4 & 2.8 & 0.9 & 11.0 & 0.9 & 13.1 & 0.3 \\ \multicolumn{8}{l}{Haemoglobin protein} & 0.3 & 0.4 & 6.8 & 0.5 & 9.2 & 1.0 & 8.9 & 0.6 \\ \multicolumn{8}{l}{Plasma protein} & 5.2 & 0.8 & 7.0 & 0.2 & 9.4 & 0.6 & 11.8 & 0.3 \\ \multicolumn{8}{l}{Technical gelatin} & 2.3 & 0.7 & 5.8 & 0.4 & 10.1 & 0.6 & 9.4 & 0.3 \\ \multicolumn{8}{l}{Wheat protein} & 5.5 & 0.5 & 8.1 & 1.2 & 7.6 & 2.4 & 8.3 & 0.2 \\ \multicolumn{8}{l}{Whey protein concentrate} & 4.0 & 0.5 & 4.7 & 1.7 & 8.2 & 0.2 & 9.5 & 0.6 \\ \hline \multicolumn{8}{l}{Average} & 3.6 & 2.6 & 6.3 & 1.9 & 9.6 & 1.3 & 10.3 & 1.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Mean crust thickness of medium-grained sand and fine-grained silica sand samples treated at biopolymer concentrations of 1 and 2 wt% (XG = 0.25 and 0.50 wt%). Tests were performed in triplicates (\(n\) = 3), with M = mean and SD = standard deviation. Water-treated control groups formed no crusts.