## 3 Results and Discussion
### Functional Properties of Rice Flours  
In order to gather information on the contribution of the main macromolecular compounds of the rice flour to the functionality of the samples, the solvent retention capacity profiles were determined, and the results are shown in Table 2.  
The values of Ca-SRC varied significantly with the investigated samples (\(p\) < 0.05). The highest values of Ca-SRC were registered for NRF. In a previous study performed on oat, [PERSON] et al. [15] showed that Ca-SRC is correlated with \(\beta\)-glucan content and reported no relationship with protein and starch contents. On the other hand, [PERSON] [20] characterized different rice cultivars grown in various locations of Thailand and reported a significant negative correlation between the \(\beta\)-glucan and amylose contents. They indicated that rice contains between 0.11 and 0.88% \(\beta\)-glucan, similar to other cereal grains, the \(\beta\)-glucan being mainly located in the starch endosperm, subaleuorne, and aleuorne cell walls. No assessment of the \(\beta\)-glucan content was performed in the present study, but a significant negative correlation was found between amylose content and Ca-SRC (R\({}^{2}\) of 0.9939 and \(p\) < 0.05; Table S1). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multicolumn{3}{c}{**Flour Samples**} \\ \cline{2-4}  & **ARF** & **BRF** & **NRF** \\ \hline Moisture, \% & 12.78 \(\pm\) 0.11 \({}^{\text{a}}\) & 12.15 \(\pm\) 0.15 \({}^{\text{b}}\) & 12.21 \(\pm\) 0.09 \({}^{\text{b}}\) \\ \hline Ash, \% & 0.46 \(\pm\) 0.01 \({}^{\text{b}}\) & 0.46 \(\pm\) 0.01 \({}^{\text{b}}\) & 1.30 \(\pm\) 0.03 \({}^{\text{a}}\) \\ \hline Protein, \% & 7.73 \(\pm\) 0.11 \({}^{\text{c}}\) & 9.99 \(\pm\) 0.10 \({}^{\text{b}}\) & 11.16 \(\pm\) 0.05 \({}^{\text{a}}\) \\ \hline Fat, \% & 1.47 \(\pm\) 0.03 \({}^{\text{b}}\) & 1.45 \(\pm\) 0.03 \({}^{\text{b}}\) & 3.42 \(\pm\) 0.07 \({}^{\text{a}}\) \\ \hline Crude fiber, \% & 2.06 \(\pm\) 0.05 \({}^{\text{b}}\) & 1.46 \(\pm\) 0.03 \({}^{\text{c}}\) & 4.75 \(\pm\) 0.05 \({}^{\text{a}}\) \\ \hline Starch, \% & 88.28 \(\pm\) 0.63 \({}^{\text{a}}\) & 86.64 \(\pm\) 0.56 \({}^{\text{b}}\) & 79.37 \(\pm\) 0.23 \({}^{\text{c}}\) \\ \hline Starch damage, \% & 9.71 \(\pm\) 0.10 \({}^{\text{a}}\) & 5.34 \(\pm\) 0.05 \({}^{\text{c}}\) & 6.26 \(\pm\) 0.05 \({}^{\text{b}}\) \\ \hline Amylose, \% & 17.40 \(\pm\) 0.17 \({}^{\text{a}}\) & 11.17 \(\pm\) 0.11 \({}^{\text{b}}\) & 6.87 \(\pm\) 0.16 \({}^{\text{c}}\) \\ \hline Fineness module & 2.15 \(\pm\) 0.05 \({}^{\text{a}}\) & 2.10 \(\pm\) 0.10 \({}^{\text{a}}\) & 1.99 \(\pm\) 0.04 \({}^{\text{a}}\) \\ \hline \hline \end{tabular}  
* ARF—Arorio rice flour; BRF—Basmati rice flour; NRF—Negro rice flour. Mean values on the same row not sharing a superscript letter are significantly different (\(p\) < 0.05).  
\end{table} 
Table 1: Physico-chemical characteristics of rice flours. Na-SRC and LA-SRC are associated with protein (glutenin) characteristics [15]. NRF had higher Na-SRC and LA-SRC values compared to BRF and ARF. In fact, both Na-SRC and LA-SRC were significantly correlated with the protein content (R\({}^{2}\) of 0.9974 and 0.9957, respectively, and \(p\) < 0.05; Table S1). SC-SRC is associated with starch damage and varied between 84.89% (BRF) and 104.1% (ARF). [PERSON] et al. [21] reported slightly higher SC-SRC values of 116.6% for rice flour, while [PERSON] et al. [22] reported SC-SRC values of 88.9% and 127.4% for two different commercial gluten free bread mixtures. The SC-SRC results were positively correlated with the damaged starch content (R\({}^{2}\) of 0.9953 and \(p\) < 0.05; Table S1). Among the investigated rice flours, the ARF presented the highest starch damage, followed by NRF and BRF (Table 1). Su-SRC provides indications on the characteristics of the pentosans found in the flour samples (AACC Method 56-11.02) [13].