EFFECTS OF BLENDING RATIOS OF BARLEY, POTATO AND FERMENTATION DURATION ON QUALITY OF SORGHUM BASED INJERA

Abstract

Injera is Ethiopian staple food, which is widely consumed in all parts of the country. Injera 100% made from sorghum flour is characterized by sticky, firm and friable, when stored. The practice of combining sorghum and potato flour for injera making and little scientific research is done on sorghum-barley-potato flour blended injera. Thus, this study was conducted to investigate the effect of blending ratio of barley and potato flour and fermentation duration on quality of sorghum based injera. The experiment was done by full factorial design with two factors; blending ratios and fermentation duration. Twelve combinations of treatments were done in triplicate. Proportions of sorghum were 80, 70, and 50%, of barley were 15, 20, and 25%, and of potato were 5, 10, and 25%. The fermentation durations were 24, 48 and 72 hour. Functional property of flours were 1.98-2.44 g/g water absorption capacity, 0.80-1.25 g/g oil absorption capacity, 56.50-69.33% disperse-ability, 8.24-11.17 g/g swelling power. The percentage of retained particle size were increased from (0.66-0.80%) to (49.82, 49.88 and 54.32%) while mesh size decreased from 500 μm to 125 μm. Bulk density and angle of repose were 0.60-0.85 g/ml and 28.63-44.30, respectively. The proximate composition of flours such as, moisture content, fat, protein, fiber, ash content, carbohydrate and total energy were 11.99-12.75%, 2.72-3.06%, 15.33-16.27%, 5.47-5.98%, 1.77-2.14%, 60.90-61.59% and 332.16-336.34 Kcal/100g, respectively. Mineral contents of flours such as zinc, calcium and iron contents were 4.91-6.34, 7.34-38.90, and 7.43-16.87 mg/100g, respectively. The mineral contents of injera were 7.98 mg/100g zinc, 15.93-19.62 mg/100g calcium, and 15.92-19.88 mg/100g iron content. Proximate composition of injera were 57.20-63.33% moisture content, 1.52-1.94% fat, 9.85-12.78% protein, 1.29-1.78% fiber, 1.80-2.34% ash content, 20.68-27.46% carbohydrate, and 139.12-165.97 Kcal/100g total energy. The pH, tannin and phytic acid of composite injera were 3.41-4.03, 14.50-16.87 mg/100g and 220.46-282.16 mg/100g, respectively. From the blended product, B1T3 was the best selected injera product.