Nutrient Composition, Quality Evaluation and Acceptability of “Gari” Fortified with Toasted African Yam Bean Seed Flour

Abstract:

Fresh peeled and grated cassava mash was blended with toasted African yam bean seed flour (TAYBSF) in ratios of 95:5, 90:10, 85:15 and 80:20 w/w cassava : African yam bean seed prior to fermentation (PreGAF samples) and after fermentation (PoGAF samples). Gari without African yam bean seed flour served as the control. Fermentation was done for 2 days after which the samples were dewatered. The dewatered samples were sieved, toasted and evaluated for chemical composition and functional properties. The level of TAYBSF and stage of inclusion had significant (p < 0.05) effect on the composition and functional properties of the samples. The PreGAF samples had higher chemical constituents than the PoGAF samples. Addition of TAYBSF led to an increase in the protein content of PreGAF samples from 2.60 to 13.74 %, crude fat from 0.52 to 0.79 % and the ash content from 0.47 to 1.91 %. Addition of TAYBSF also led to an increase in the crude protein content of PoGAF samples from 2.60 to 12.07 %, crude fat from 0.52 to 1.25 % and the ash content from 0.47 to 1.67 %. The total amino acid (TAA) content of PreGAF and PoGAF samples were significantly (p < 0.05) higher than that of the control sample with values ranging from 59.83 to 78.74 g/100g and 58.04 to 66.34 g/100g for PreGAF and PoGAF samples respectively while the control sample had a TAA content of 55.83 g/100g. The total essential amino acid (TEAA) content of PreGAF samples increased from 25.64 to 35.62 g/100g while that of PoGAF samples increased from 25.64 to 30.30 %. The anti-nutrient (hydrogen cyanide-HCN) content of PoGAF samples slightly increased from 0.0460 to 0.1020 mg/100g while the HCN of PreGAF samples increased from 0.0460 to 0.0750 mg/100g with increase in the level of inclusion of TAYBSF. Increasing the level of TAYBSF addition increased (p < 0.05) the bulk density of PreGAF samples from 0.56 to 0.71 g/cm3 and in PoGAF samples from 0.56 to 0.67 g/cm3 but caused significant (p < 0.05) reduction in the water absorption capacity from 475 to 276 % and from 475 to 320 % for PoGAF and PreGAF samples respectively. The peak viscosities of the samples were reduced from 1370 to 153 cp in PreGAF and from 1592 to 1206 cp in PoGAF as the level of TAYBSF addition increased while the control sample had a peak viscosity of 2264 cp. Acceptability of the fortified samples decreased (p < 0.05) with increase in the level of addition of TAYBSF. Samples fortified with the lowest level of TAYBSF after fermentation (PoGAF5) compared favourably with the control sample in appearance, flavor, texture, mouldability and general acceptability with sensory scores of 7.33, 6.70, 7.03, 6.97 and 7.10 respectively. Samples that were fortified post fermentation with the lowest level of TAYBSF were most preferred by the panelists.