## 3 Results and Discussions
### Total Phenolic Contents, Antioxidant Activities, and Mineral Content  
The results of total phenolic content (TPC), antioxidant activities (ABTS, DPPH, FRAP), and mineral composition (calcium, magnesium, iron, and zinc) in cassava root flour over different fermentation durations (0 h, 12 h, 24 h, and 48 h) are shown in Table 2. The results highlight significant improvements in TPC, antioxidant properties, and mineral content, suggesting that natural fermentation enhances cassava root flour's nutritional and functional qualities. It should be noted that the TPC validity is shown in relation to other complementary indirect antioxidant activities such as DPPH, FRAP, and ABST that are determined in this study. Phenolic compounds are natural antioxidants that contribute to a plant-based foods' functional and health benefits [34]. The TPC increased from 1.35 mg GAE/g in the control to 2.97 mg GAE/g at 48 h of fermentation. This enhancement can be attributed to microbial enzyme activity (e.g., polyphenol oxidases and glucosidases), which break down bound phenolic compounds into their free, more bioavailable forms [35]. Fermentative breakdown of complex carbohydrates, which release bound phenolic compounds, leads to an increase in TPC [9]. A similar trend was observed for antioxidant activities, measured using ABTS, DPPH, and FRAP assays. ABTS radical scavenging activity increased from 23.50 umol TE/g (control) to 69.81 umol TE/g at 48 h, indicating an improvement in the overall antioxidant potential of cassava root flour. The DPPH radical scavenging activity (IC\({}_{50}\) values) increased progressively from 40.33 ug/mL (control) to 92.61 ug/mL after 48 h, suggesting a more substantial capacity to neutralize free radicals. The FRAP (ferric reducing antioxidant power) values followed a similar pattern, increasing from 35.23 umol Fe\({}^{2+}\)/g in the control to 82.30 umol Fe\({}^{2+}\)/g after 48 h, indicating improved reducing power and metal ion chelation ability. The increase in the antioxidant activities of the fermented cassava root flour may be attributed to an increase in the TPC, which involves the action of microorganisms in breaking down bound polyphenols in the samples. These findings suggest that natural \begin{table}
\begin{tabular}{c c c c c} \hline
**Samples** & **Control** & **12 h** & **24 h** & **48 h** \\ \hline TPC (mg GAE/g) & 1.35 \({}^{\text{a}}\) \(\pm\) 0.3 & 1.95 \({}^{\text{b}}\)\(\pm\) 0.5 & 2.56 \({}^{\text{c}}\)\(\pm\) 0.4 & 2.97 \({}^{\text{d}}\)\(\pm\) 0.6 \\ ABTS (\(\upmu\)mol TE/g) & 23.50 \({}^{\text{a}}\)\(\pm\) 0.4 & 37.92 \({}^{\text{b}}\)\(\pm\) 0.6 & 54.40 \({}^{\text{c}}\)\(\pm\) 0.7 & 69.81 \({}^{\text{d}}\)\(\pm\) 0.8 \\ DPPH (IC\({}_{50}\), ug/mL) & 40.33 \({}^{\text{a}}\)\(\pm\) 0.8 & 60.24 \({}^{\text{b}}\)\(\pm\) 0.5 & 78.40 \({}^{\text{c}}\)\(\pm\) 0.6 & 92.61 \({}^{\text{d}}\)\(\pm\) 0.7 \\ FRAP (\(\upmu\)mol Fe\({}^{2+}\)/g) & 35.23 \({}^{\text{a}}\)\(\pm\) 0.6 & 52.73 \({}^{\text{b}}\)\(\pm\) 0.8 & 68.51 \({}^{\text{c}}\)\(\pm\) 0.7 & 82.30 \({}^{\text{d}}\)\(\pm\) 0.8 \\ \hline Calcium (mg/100 g) & 32.50 \({}^{\text{a}}\)\(\pm\) 1.2 & 35.61 \({}^{\text{b}}\)\(\pm\) 1.3 & 38.91 \({}^{\text{c}}\)\(\pm\) 0.4 & 41.35 \({}^{\text{d}}\)\(\pm\) 0.5 \\ Magnesium (mg/100 g) & 21.81 \({}^{\text{a}}\)\(\pm\) 0.9 & 23.24 \({}^{\text{b}}\)\(\pm\) 1.0 & 24.60 \({}^{\text{c}}\)\(\pm\) 1.1 & 26.12 \({}^{\text{d}}\)\(\pm\) 0.7 \\ Iron (mg/100 g) & 5.42 \({}^{\text{a}}\)\(\pm\) 0.2 & 6.11 \({}^{\text{b}}\)\(\pm\) 0.2 & 6.82 \({}^{\text{c}}\)\(\pm\) 0.3 & 6.82 \({}^{\text{c}}\)\(\pm\) 0.3 \\ Zinc (mg/100 g) & 1.74 \({}^{\text{a}}\)\(\pm\) 0.1 & 2.10 \({}^{\text{b}}\)\(\pm\) 0.1 & 2.40 \({}^{\text{c}}\)\(\pm\) 0.3 & 2.62 \({}^{\text{d}}\)\(\pm\) 0.1 \\ \hline \end{tabular} Mean values with different superscripts in a column are significantly (\(p\leq\) 0.05) different from each other.  
\end{table} 
Table 2: Effects of natural fermentation time on cassava root flour’s total phenolic content, antioxidant activities, and mineral content.