# Water-Soluble Sugars of Pedigreed Sorghum Mutant Stalks and Their Recovery after Pretreatment
## 3 Results and Discussion  
### Physical and Chemical Properties of Pedigreed Sorghum Mutant Stalks  
Sixteen sorghum mutant stalks with evenly distributed water-extractive contents ranging from the lowest, 18%, to the highest, 52%, were selected for this study (Table 1). The carbon and oxygen contents of selected samples ranged from 37.4% to 41.4% and 49.2% to 55.3%, respectively. The hydrogen content was approximately 5% to 6%, and nitrogen and sulfur contents were typically less than 2%. The wild-type sorghum samples (E25a and E25b, referred to as the control) contained relatively low water-extractive content of 25.8% with an average of 39.4% carbon, 52.5% oxygen, 6.4% hydrogen, 0.8% nitrogen, and 1.3% sulfur contents (Table 1). The selected sorghum mutants with higher water-extractive contents were expected to contain significantly larger portions of non-structural carbohydrates, including sucrose, glucose, and fructose, as compared to the control wild-type sorghum biomass (Table 2). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **Water-Soluble** & **Carbon** & **Hydrogen** & **Nitrogen** & **Sulfur (\%)** & **Oxygen** & **Heating Value** \\
**Identity** & **Extractive (\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline E18A & 17.6 \(\pm\) 0.6a \({}^{1}\) & 40.3 \(\pm\) 0.8a & 6.4 \(\pm\) 0.2a & 0.96 \(\pm\) 0.3a & 1.3 \(\pm\) 0.3a & 51.1 \(\pm\) 0.6a & 16,419.5 \(\pm\) 21a \\ E18B & 18.7 \(\pm\) 0.8a & 41.4 \(\pm\) 0.9a & 6.5 \(\pm\) 0.3a & 0.91 \(\pm\) 0.2a & 1.3 \(\pm\) 0.2a & 49.9 \(\pm\) 0.7a & 17,047.4 \(\pm\) 31a \\ E20A & 21.2 \(\pm\) 0.9b & 38.9 \(\pm\) 1.3b & 5.6 \(\pm\) 0.2b & 0.64 \(\pm\) 0.3b & 1.2 \(\pm\) 0.2a & 53.6 \(\pm\) 0.8a & 15,935.1 \(\pm\) 26b \\ E20B & 21.0 \(\pm\) 0.8b & 37.4 \(\pm\) 0.7b & 5.5 \(\pm\) 0.4b & 0.73 \(\pm\) 0.1b & 1.1 \(\pm\) 0.1a & 55.3 \(\pm\) 0.4b & 14,748.6 \(\pm\) 19b \\ E25A & 25.4 \(\pm\) 1.3b & 39.4 \(\pm\) 1.6a & 6.4 \(\pm\) 0.1a & 0.77 \(\pm\) 0.2b & 1.2 \(\pm\) 0.1a & 52.2 \(\pm\) 0.5a & 16,039.3 \(\pm\) 21b \\ E25B & 26.3 \(\pm\) 1.6b & 39.4 \(\pm\) 0.7a & 6.4 \(\pm\) 0.2a & 0.73 \(\pm\) 0.3b & 1.3 \(\pm\) 0.2a & 52.2 \(\pm\) 0.6a & 15,953.4 \(\pm\) 18b \\ E30A & 30.3 \(\pm\) 1.8c & 39.5 \(\pm\) 0.6a & 6.4 \(\pm\) 0.3a & 1.10 \(\pm\) 0.2c & 1.5 \(\pm\) 0.2b & 51.5 \(\pm\) 0.7a & 16,651.4 \(\pm\) 25a \\ E30B & 30.3 \(\pm\) 1.6c & 41.1 \(\pm\) 1.5a & 6.5 \(\pm\) 0.4a & 1.83 \(\pm\) 0.3c & 1.5 \(\pm\) 0.2b & 49.2 \(\pm\) 0.6c & 17,327.4 \(\pm\) 24a \\ E35A & 35.3 \(\pm\) 2.2d & 38.9 \(\pm\) 1.8b & 5.8 \(\pm\) 0.5b & 0.72 \(\pm\) 0.1b & 1.2 \(\pm\) 0.1a & 53.4 \(\pm\) 0.8a & 16,071.9 \(\pm\) 29b \\ E35B & 35.3 \(\pm\) 2.1d & 39.9 \(\pm\) 0.9a & 5.2 \(\pm\) 0.2b & 0.92 \(\pm\) 0.2a & 0.9 \(\pm\) 0.1c & 53.0 \(\pm\) 0.9a & 16,510.8 \(\pm\) 28a \\ E40A & 40.3 \(\pm\) 2.3d & 38.6 \(\pm\) 0.8a & 5.6 \(\pm\) 0.3b & 1.07 \(\pm\) 0.1a & 1.1 \(\pm\) 0.2a & 53.6 \(\pm\) 0.6a & 16,085.9 \(\pm\) 28b \\ E40B & 40.8 \(\pm\) 1.9d & 38.3 \(\pm\) 0.7a & 5.9 \(\pm\) 0.5a & 0.68 \(\pm\) 0.1b & 1.2 \(\pm\) 0.1a & 53.9 \(\pm\) 1.1d & 16,1443.3 \(\pm\) 22b \\ E45A & 45.1 \(\pm\) 2.3e & 37.6 \(\pm\) 0.5a & 5.8 \(\pm\) 0.4b & 1.01 \(\pm\) 0.2a & 1.2 \(\pm\) 0.2a & 54.4 \(\pm\) 1.2d & 16,035.2 \(\pm\) 17b \\ E45B & 46.4 \(\pm\) 2.1e & 39.0 \(\pm\) 0.6a & 5.9 \(\pm\) 0.6a & 1.00 \(\pm\) 0.2a & 1.2 \(\pm\) 0.1a & 52.9 \(\pm\) 0.8a & 16,461.8 \(\pm\) 26a \\ E52A & 52.7 \(\pm\) 2.5e & 39.7 \(\pm\) 0.8b & 5.5 \(\pm\) 0.3b & 0.78 \(\pm\) 0.1b & 1.1 \(\pm\) 0.1a & 52.9 \(\pm\) 0.5a & 16,594.9 \(\pm\) 25a \\ E52B & 53.4 \(\pm\) 2.6e & 40.0 \(\pm\) 1.3b & 5.8 \(\pm\) 0.4b & 0.70 \(\pm\) 0.1b & 1.8 \(\pm\) 0.2d & 51.8 \(\pm\) 0.7a & 16,436.9 \(\pm\) 21a \\ \hline \hline \end{tabular} Note: Samples E25A and E25B are wild-type sorghum used as control; the remaining samples are pedigreed sorghum mutant stalks. \({}^{1}\) Column means with different letters than the control are significantly different at the 0.05 level.  
\end{table} 
Table 1: Physico-chemical characteristics of sorghum stalks.