Improving the quality of sorghum injera by decortication and compositing with tef

Abstract

Injera is an Ethiopian fermented pancake-like bread made from cereals, with tef being preferred. Decortication and compositing with tef were evaluated as methods to improve the injera-making quality of red tannin-free and tannin-containing sorghums. Both decortication and compositing improved sorghum injera quality. Concerning decortication, mechanical abrasion was found to be more effective than hand pounding because acceptable injera was obtained with lower milling loss. Good quality injera was produced at an extraction rate of 540 g kg −1 for tannin-containing and 830 g kg −1 for tannin-free sorghum. With compositing, good quality injera was produced with a 50:50 (w/w) composite of whole tannin-containing sorghum and tef. Both processes reduced the tannin content of the flours, which appeared to relieve the inhibiting effects of tannins on the fermentation. Decortication also seemed to improve sorghum flour injera-making quality by improving flour pasting as a result of reducing the level of interfering substances such as lipids and proteins. In contrast, the improvement brought about by compositing with tef seemed to be due to inherent differences between tef and sorghum starch granules and an increase in the water solubility index of the flour. Compositing seems to be a more useful method of improving sorghum injera quality than decorticating as it avoids the grain loss associated with decortication.

Impact of variety type and particle size distribution on starch enzymatic hydrolysis and functional properties of tef flours

“…Similarly the effect of flour mean particle size was important (p < 0.05 and r = −0.5 to −0.6) on gel hydration properties of the tef flours and this could be due to higher surface area being exposed for water binding. Earlier work by Yetneberk et al (2005) shows that in sorghum and tef composite flours the WSI increased progressively with increasing proportion of tef, giving injera better quality. The increase in WSI agreed with the observation that, during mixing, compared with sorghum, tef dough tended to be stickier and water-soluble components in the tef flour could have modified the dough rheology and the texture of injera positively (Yetneberk et al, 2005).…”

“…Earlier work by Yetneberk et al (2005) shows that in sorghum and tef composite flours the WSI increased progressively with increasing proportion of tef, giving injera better quality. The increase in WSI agreed with the observation that, during mixing, compared with sorghum, tef dough tended to be stickier and water-soluble components in the tef flour could have modified the dough rheology and the texture of injera positively (Yetneberk et al, 2005). In evaluating injera making potentials of sorghum varieties higher WSI gave more fluffy, soft and rollable injera (Yetnebrerk, 2004).…”

“…Intrinsic tef flour quality factors which favor these quality aspects include starch granule characteristics and the higher water solubility index of tef flour which positively influence injera quality (Yetneberk, Rooney, & Taylor, 2005). The effect of milling method on starch damage, flour physical and functional properties and end product quality for common cereals like wheat and rice is well known (Al-Rabadi et al, 2009;Kadan et al, 2008;Tran et al, 2011).…”

Effect of different cereal blends on the quality of Injera a staple food in the highlands of Ethiopia

“…The same report also indicated that sensory quality differences are governed mainly by varietal inherent differences with less impact from environmental factors. Yetneberk et al (2005) also reported that decortication of sorghum and compositing with tef improved injera quality. In the study of injera made from tef, Parker et al (1989) reported that tef starch played a major role in the formation of injera surface gas holes.…”

“…This is due to its softer texture, preferred taste and colour (Yetneberk et al, 2005;Abraha et al, 2013). Normally, injera with uniformly distributed surface gas holes, soft plumpness, non-sticky and having slightly sweet taste is commonly preferred by injera consumers (Abraha et al, 2013).…”