# Characterization of Sorghum Processed through Dry Heat Treatment and Milling
## 3 Results and Discussion
### Functional Properties and Proximate Composition
#### 3.1.1 Influence of Factors
\begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Factor**} & **HC** & **OAC** & **SP** & **WRC** & **EA** & **ES** & **Protein** & **Fat** & **Ash** & **Moisture** & **Carohydrates** \\  & **(\%)** & **(\%)** & **(g/g)** & **(g/g)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** \\ \hline Constant & 96.17 & 164.78 & 3.85 & 0.90 & 45.36 & 61.67 & 9.85 & 4.09 & 1.39 & 9.28 & 68.80 \\ A & 1.77 & \(-\)1.86 & 0.14 \({}^{**}\) & \(-\)0.07 \({}^{**}\) & 1.53 \({}^{**}\) & 0.50 & \(-\)0.24 \({}^{**}\) & 0.28 \({}^{*}\) & 0.06 \({}^{*}\) & \(-\)0.41 \({}^{**}\) & 0.30 \\ B & 4.16 \({}^{*}\) & \(-\)9.73 \({}^{**}\) & \(-\)0.41 \({}^{**}\) & 0.11 \({}^{**}\) & 5.63 \({}^{**}\) & 1.25 \({}^{*}\) & 1.01 \({}^{**}\) & \(-\)1.84 \({}^{**}\) & \(-\)0.77 \({}^{**}\) & \(-\)0.17 \({}^{**}\) & 1.44 \({}^{**}\) \\ A \(\times\) B & 1.37 & \(-\)0.21 & \(-\)0.05 & \(-\)0.07 \({}^{*}\) & 2.12 \({}^{**}\) & 2.75 \({}^{**}\) & \(-\)0.22 \({}^{*}\) & \(-\)0.08 & 0.16 \({}^{**}\) & 0.08 \({}^{*}\) & \(-\)0.30 \\ \multicolumn{8}{c}{Model fitting} \\ \(p\)-value & \(<\)0.05 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.01 & \(<\)0.05 \\ \(R^{2}\) & 0.58 & 0.69 & 0.90 & 0.73 & 0.93 & 0.68 & 0.90 & 0 Fractionation exhibited significant positive (\(p<0.01\)) effects (Table 3) on sorghum flour WRC, while treatment temperature and the interaction between factors had a negative influence (\(p<0.05\)). The increase in fraction dimensions resulted in proportional rise of flour WRC (Figure 3b), while an opposite trend was obtained when temperature was increased. The reduction in WRC at the higher treatment temperature could be due to physical damage to the fiber structure at high temperatures, which may lead to changes in water-retention ability [35]. Heat treatment causes a rupture of weak linkages between polysaccharide chains, high temperatures also being able to break the glycosidic bonds in the polysaccharides [35]. The structure of sorghum flour particles comprising nanopores could be responsible for the water binding of sorghum flour, since this water is likely to be retained even when subjected to external forces, such as centrifugation due to capillary forces and the cell walls' mechanical strength [30]. The EA and ES parameters were positively influenced by treatment temperature and fractionation (\(p<0.05\)), while the interaction between factors showed significant positive influence (\(p<0.05\)) (Table 3). The EA is mainly dependent on the dispersion of proteins at the surface tension of water and air by unfolding its structure, while ES is determined by the creation of a dense cohesive layer around the air bubble [36]. Similar enhancement of the emulsifying properties was obtained by [PERSON] et al. [36] when radio-frequency heat treatment was applied to maize grains. The increase in protein content as the fraction dimension was higher could represent an explanation for the enhanced EA and ES of sorghum flour with greater fraction size. The different nutritional composition could be explained by the different fractions obtained from sieving. Sorghum flour protein content was positively influenced (at \(p<0.01\)) by fractionation (Figure 4a), while treatment temperature and the interaction between factors had a  
Figure 3: Three-dimensional graphic showing the combined effects of factors (treatment temperature and fractions) on the sorghum flour: (**a**) hydration capacity (HC), (**b**) water-retention capacity (WRC), (**c**) swelling power (SP), (**d**) oil-absorption capacity (OAC), (**e**) emulsion activity (EA), and (**f**) emulsion stability (ES). significant negative effect. Treatment temperature significantly influenced (\(p<0.05\)) in a positive way fat and ash content, while the fractionation negatively affected (\(p<0.01\)) these parameters (Table 3).