## 3 Results and Discussions  
### The pH, TTA, TSS, Crude Protein, IVPD, Vitamin C, and Antintutitional Factors  
The results in Table 1 demonstrate the progressive biochemical and nutritional transformations occurring in cassava root flour during natural fermentation over a 48 h period. The results of pH, total titratable acidity (TTA), total soluble solids (TSS), crude protein,in vitro protein digestibility (IVPD), vitamin C content, and antinutritional factors (phytates, hydrogen cyanide, and trypsin inhibitor activity) provide key insights into the functional and nutritional implications of fermentation. There was a significant decrease in pH from 6.50 (control) to 4.20 (48 h), indicating increased microbial activity and acid production during fermentation. This acidification is attributed to the metabolic activity of lactic acid bacteria (LAB) and yeasts, which ferment available carbohydrates into organic acids, primarily lactic acid, during fermentation. The corresponding increase in TTA (from 0.12% to 0.81% lactic acid) further confirms the acidification process. The total soluble solids (TSS), representing simple sugars and soluble compounds, decreased significantly from 5.82 \({}^{\circ}\)Brix (control) to 2.12 \({}^{\circ}\)Brix (48 h). This reduction is expected, as fermentative microorganisms utilize sugars as an energy source for growth and metabolism, producing organic acids and bioactive compounds as by-products. There was a notable increase in crude protein content from 1.82% in the control to 3.01% after 48 h of fermentation. This enhancement in crude protein content may be attributed to microbial biomass accumulation [25]. This finding is in line with the findings of [PERSON] et al. [26], who reported an increase in crude protein of solid-state fermented maize flour. In vitro protein digestibility (IVPD), an indicator of protein bioavailability, increased significantly from 47.32% in unfermented cassava root flour (control) to 78.51% at 48 h. This improvement can be attributed to proteolytic enzyme activity from fermenting microbes, which break down complex proteins into peptides and free amino acids [27]. Additionally, fermentation reduces protein-bound antinutrients, further enhancing digestibility [28]. This result is similar to that reported by [PERSON] et al. [29], who reported an increase in the in vitro protein digestibility of fermented cassava mahewu after 42 h.  
The vitamin C content of the samples (unfermented and fermented cassava root flour) increased from 20.52 mg/100 g in the control to 35.23 mg/100 g at 48 h. The increase in the vitamin C content may be due to microbial synthesis of ascorbic acid by certain bacteria and yeasts and increased enzymatic conversion of precursor molecules [30]. The improved vitamin C content indicates fermentation's potential to enhance cassava flour's nutritional profile, particularly in regions with prevalent vitamin C deficiencies. Natural fermentation significantly decreased phytates, hydrogen cyanide (HCN) levels, and trypsin inhibitor activity (TIA), all major antinutritional factors in cassava roots. Phytates, known for chelating essential minerals and reducing bioavailability, decreased from 205.43 mg/100 g (control) to 72.72 mg/100 g (48 h). This reduction is linked to the