Effect of Fermentation on the Nutrient and Antinutrient Composition of African Yam Bean (Sphenostylisstenocarpa) Seeds And Pearl Millet (Pennisetumglaucum) Grains

Abstract

Aims: The study evaluated the effect of fermentation on the nutrient and antinutrient composition of African Yam bean seeds and pearl millet grains.

Methodology: Fermentation was done for 24, 48 and 72h. The flours produced after each fermentation periods where analysed using the standard assay methods.The protein, ash, crude fibre and fat content of the samples were analysed using the standard methods of AOAC (9). Carbohydrate was determined by difference (The summation of all the proximate values was subtracted from 100%). Thus:  % carbohydrate = 100% - (% crude protein + % fat + % ash + %Crude fibre + % moisture) The minerals Calcium, (Ca), Iron (Fe), Magnesium (Mg), Zinc (Zn) and Phosphorus (P) were determined by atomic absorption spectrophotometer. The tannin level of the flours were determined by the modified vanillin-HCL method of Price and Buttler⁽⁴⁰⁾, while phytate was estimated by a photometric method of Latta and Eskin⁽⁴¹⁾.

Results: Fermentation increased the protein and ash levels in both flour samples (24.70 to 28.70%). It increased fat in millet (4.06 - 4.68% vs. 3.98%) relative to the control. Carbohydrate content of the flours was decreased due to fermentation. The Fe, Zn, Mg, Ca, and P levels were significantly increased in the fermented flours of AYB and pear millet with the exception of calcium for millet (P< 0.05) Fermentation reduced the tannin levels in both flours as against the control (0.51 to 0.31 mg) and (0.16 to 0.02mg) respectively. The phytate content was also reduced from 0.49 to 0.25mg and 0.26 to 0.06mg.

Conclusion: The importance of fermentation in the processing of plant foods cannot be over emphasized, in that it is one of the simplest and cheap food processing techniques for improving the nutritional quality of local staples in many homes.