The Effect of Blending Ratio of Tef [Eragrostis Tef (Zucc) Trotter], Sorghum (Sorghum bicolor (L.) Moench) and Faba Bean (Vicia faba) and Fermentation Time on Chemical Composition of Injera

Abstract

Background: This study was conducted to determine the effect of tef [Eragrostis tef (Zucc) Trotter], sorghum (Sorghum bicolor (L.) Moench) and faba bean (Vicia faba) blending ratio and fermentation time on chemical composition of Injera. Methods: The effect of two factors, blending ratio (tef, sorghum and faba bean) and fermentation time at 24 h, 48 h and 72 h were studied. The experiment was conducted using custom design. Results: Both the linear terms and the interaction terms of tef, sorghum and faba bean had significant (P<0.05) effect on the proximate composition of the blend Injera. The mixture of faba bean and sorghum with tef increased the ash, carbohydrate, energy content, fiber, moisture and protein content of the blend injera. The result shows the increased protein content which less in amount in tef Injera was because of faba bean and sorghum which contain more protein as compared to tef. Significant (P<0.05) increased in moisture and protein content was observed on long fermentation time (72 h). However ash, fat, fiber, carbohydrate and energy were shown on short fermentation time. Thus, short fermentation time gives more caloric food than long fermentation time. On the two dimensional mixtures contour plot the optimum value (maximum amount) of protein was observed when 55% tef, 30% sorghum and 15% faba bean were blended and fermented at 72 h. on carbohydrate the maximum amount or optimum was shown when 65% tef, 30% sorghum and 5% faba bean were mixed and fermented for 24 h. Also on the energy content the optimum value or maximum amount was shown when 70% tef, 20% sorghum and 10% faba bean were mixed and fermented at 24 h. Conclusion: The result showed that good quality Injera in nutritional composition can be obtained by the blend of 55% tef, 30% sorghum and 15% faba bean at 72 h fermentation time. The optimum value of all chemical composition was obtained when more sorghum (30%) and faba bean (15%) were mixed in to 55% tef flour and fermented at 72 h.