Nutritional composition and sensory quality of injera prepared from tef (Eragrostis tef (Zucc.) Trotter) complemented with lupine (Lupinus spp.)

There is currently an emerging problem of protein malnutrition in Ethiopia. This food formulation was done to increase the accessibility of nutrient-rich food products for the consumers. Lupine is a legume crop, which is an excellent source of protein. This study aimed to investigate the effect of tef, lupine varieties and blending ratio on the chemical composition of injera and sensory acceptability of Ethiopians staple food. The effect of blending ratio and lupine varieties (Australian sweet lupine and Dibettered lupine seed) were studied. The formulations were generated by using mixture design software. Lupine variety and blending proportion had significant (P < 0.05) effect on proximate, mineral, anti-nutritional compositions and sensory acceptability of blended injera. The nutritional compositions of formulated injera ranged from 60.37 to 66.97%, 1.76 to 2.05 %, 11.78 to 18.84 %, 2.53 to 4.01 %, 2.83 to 3.16%, 72.55 to 81.32% and 393.19 to 400.91 kcal/100 g for moisture content, total ash, crude protein, crude fat, crude fiber, utilizable carbohydrate and gross energy, respectively. The result showed that the crude protein content highly increased as the proportion of lupines increased. Crude protein and crude fat contents were higher for injera blended with dibettered lupine seed variety while crude fiber content was higher for those blended with Australian sweet lupine variety because of the raw material. Mineral content of composite injeras varied from 12.26 to 14.98 mg/100 g, 2.39 to 2.83 mg/100 g, and 145.31 to 163.96 mg/100 g for iron, zinc and calcium contents, respectively. All three mineral contents were higher in tef blended with dibettered lupine seed variety. The Tannin and phytic acid contents ranged from 9.59 to 11.95 mg/100 g and 98.91 to 120.64 mg/100 g, respectively. Therefore, this study showed significant increment in protein content of injera and provides insights for use of Lupine-tef flour mixture at home and industry level for enriched injera. As the sensory acceptability scores data indicated for both lupine varieties blended with tef for the production of injeras of up to 15% lupines almost all sensory attributes showed higher scores without significantly different among them but after 15% lupine addition there were observed drop of the sensory acceptability scores in a 7 point hedonic scale.