# Characterization of Sorghum Processed through Dry Heat Treatment and Milling
## 3 Results and Discussion
### Characterization of the Optimal Samples
#### 3.2.1 Total Polyphenols, DPPH Antiradical Activity (AA), and Starch Digestibility
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline \multirow{2}{*}{**Property**} & \multicolumn{4}{c}{**Sample**} \\ \cline{2-7}  & **Optimal S** & **Control S** & **Optimal M** & **Control M** & **Optimal L** & **Control L** \\ \hline TPC (mg GAE/g) & 21.76 \(\pm\) 0.00 \({}^{\text{AB}}\) & 21.06 \(\pm\) 0.08 \({}^{\text{FG}}\) & 25.80 \(\pm\) 0.06 \({}^{\text{WA}}\) & 21.74 \(\pm\) 0.00 \({}^{\text{AF}}\) & 11.01 \(\pm\) 0.00 \({}^{\text{LC}}\) & 16.10 \(\pm\) 0.06 \({}^{\text{HI}}\) \\ DPPH AA (\%) & 89.22 \(\pm\) 0.14 \({}^{\text{YB}}\) & 99.81 \(\pm\) 0.00 \({}^{\text{AF}}\) & 97.57 \(\pm\) 0.14 \({}^{\text{ZA}}\) & 99.03 \(\pm\) 0.00 \({}^{\text{WG}}\) & 77.57 \(\pm\) 0.14 \({}^{\text{LC}}\) & 85.34 \(\pm\) 0.14 \({}^{\text{HI}}\) \\ RDS (g/100 g) & 9.38 \(\pm\) 0.04 \({}^{\text{AB}}\) & 8.45 \(\pm\) 0.04 \({}^{\text{G}}\) & 10.02 \(\pm\) 0.02 \({}^{\text{WA}}\) & 9.75 \(\pm\) 0.04 \({}^{\text{AF}}\) & 4.57 \(\pm\) 0.06 \({}^{\text{JC}}\) & 4.29 \(\pm\) 0.04 \({}^{\text{KH}}\) \\ SDS (g/100 g) & 0.66 \(\pm\) 0.04 \({}^{\text{AB}}\) & 0.46 \(\pm\) 0.08 \({}^{\text{HI}}\) & 1.02 \(\pm\) 0.02 \({}^{\text{WA}}\) & 1.00 \(\pm\) 0.00 \({}^{\text{WF}}\) & 0.29 \(\pm\) 0.02 \({}^{\text{LC}}\) & 0.77 \(\pm\) 0.08 \({}^{\text{JC}}\) \\ TDS (g/100 g) & 12.68 \(\pm\) 0.02 \({}^{\text{AB}}\) & 11.63 \(\pm\) 0.02 \({}^{\text{JC}}\) & 13.53 \(\pm\) 0.02 \({}^{\text{WA}}\) & 13.13 \(\pm\) 0.06 \({}^{\text{AF}}\) & 11.38 \(\pm\) 0.04 \({}^{\text{JC}}\) & 10.97 \(\pm\) 0.02 \({}^{\text{HI}}\) \\ RS (g/100 g) & 4.04 \(\pm\) 0.05 \({}^{\text{AB}}\) & 3.65 \(\pm\) 0.02 \({}^{\text{YC}}\) & 8.45 \(\pm\) 0.05 \({}^{\text{WA}}\) & 8.33 \(\pm\) 0.07 \({}^{\text{WF}}\) & 3.90 \(\pm\) 0.05 \({}^{\text{YC}}\) & 3.55 \(\pm\) 0.05 \({}^{\text{KG}}\) \\ Total Starch & 16.73 \(\pm\) 0.03 \({}^{\text{AB}}\) & 15.28 \(\pm\) 0.04 \({}^{\text{YC}}\) & 21.98 \(\pm\) 0.07 \({}^{\text{WA}}\) & 21.46 \(\pm\) 0.13 \({}^{\text{AF}}\) & 15.29 \(\pm\) 0.01 \({}^{\text{JC}}\) & 14.51 \(\pm\) 0.07 \({}^{\text{HH}}\) \\ \hline \hline \end{tabular}  
* TPC—total polyphenol content, DPPH AA—DPPH antiradical activity, RS—resistant starch, SDS—slowly digestible starch, RDS—rapidly digestible starch, TDS—total digestible starch, different letters in the same row indicate significant differences among optimal and control sample (x,y for S fraction, w,z for M fraction, and j,k for L fraction), different capital letters in the same row indicate significant differences among control samples (A–C) and among optimal samples (F–H) with various particle sizes (\(p<0.05\)).  
\end{table} 
Table 6: Total polyphenols, antiradical activity, and starch digestibility of optimal and control samples. treatment [47], a fact that may possibly explain the lower SDS in the L optimal sample compared to the control, since it had the lowest lipid content (Table 5). Furthermore, the formation of polyphenol-starch complexes during treatment could also be related to this decrease, it being known that the bran is richer in phenolic compounds compared to other fractions [44; 48]. The results for RS and total starch were comparable with those previously reported [37]. The increase in digestible starch content with fraction dimension reduction is the result of the higher substrate-enzyme contact surface and/or of the different composition of the fractions. Starch digestibility is directly influenced by granule size, structure, crystalline pattern, degree of crystallinity, presence of pores or channels on the granule surface, degree of polymerization, nonstarch components, and their interactions with starch [20]. [PERSON] et al. [49] reported that dry heat treatment methods were found to increase RS content in both rice and barnyard millet, depending on the temperature and time. These results could be due to the reorganization of amylose and amylopectin chains of starch during heating [50].