Fermentation-Driven Changes in the Nutritional Quality and Anti-Nutritional Profile of Yellow-Root Cassava Gari

This study investigated the effect of fermentation duration on the proximate composition, vitamin A content and selected anti-nutritional factors of yellow-root cassava gari. Yellow-root cassava roots were processed into gari following fermentation for 24, 48, 72 and 96 h, while commercial gari served as the control. The samples were analyzed for moisture, protein, ash, crude fibre, fat, carbohydrate and vitamin A, as well as tannin, phytate, oxalate, saponin, trypsin inhibitors and hydrogen cyanide (HCN). The data were subjected to analysis of variance, and significant means were separated using the least significant difference (LSD) test at P ≤ 0.05. Fermentation duration significantly affected the proximate composition and vitamin A content of the gari samples. Protein increased progressively from 1.41% at 24 h to 2.22% at 96 h, while ash increased from 0.27 to 0.42% and crude fibre from 1.29 to 1.67%. Fat increased from 1.15 to 1.57%, whereas carbohydrate varied from 85.74 to 83.98% across the 24–96 h fermentation period. Vitamin A increased from 3441.35 at 24 h to 4987.24 at 96 h. Fermentation was associated with progressive reductions in the measured anti-nutritional factors. Tannin declined from 0.48 to 0.09 mg/100 g, phytate from 1.17 to 0.64 mg/100 g, oxalate from 0.82 to 0.54 mg/100 g, saponin from 0.63 to 0.35 mg/100 g, trypsin inhibitors from 4.76 to 1.61 TU/g and HCN from 0.42 to 0.13 mg/kg between 24 and 96 h. The findings demonstrate that fermentation duration markedly influences the nutritional and anti-nutritional characteristics of yellow-root cassava gari and contributes to the reduction of several undesirable compounds.