The quality of injera is determined in part by the extent of fermentation. In general, children are given lightly fermented injera with mild sourness. A slight increase in tyrosine, lysine and methionine content was observed when sorghum flour was made into fermented bread. Baking at 300 C for 15 minutes decreased arginine, cystine and lysine content in pearl millet bread. Eggum et al.
Sorghum is deficient in lysine and therefore has a low biological value.
On the other hand, the true digestibility of protein, as well as digestible energy, is very high, with values above 90 percent. Many studies have been done to explore the potential for making loaf bread with composite flours that include either sorghum or millet, and there are no technical difficulties in using any of these flours. There is always a steady deterioration of bread quality as the percentage of non-wheat flour is increased. In most other cases the limiting factor is the density of the loaf. Cakes and biscuits can be made using flour with much higher levels of non-wheat flour, but again, as with bread, the quality of the product deteriorates as the substitution level increases.