Influence of processing parameters on eye size and elasticity of tef-based injera

Open Access
Author:
Attuquayefio, Wendy Darling
Graduate Program:
Food Science
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 22, 2014
Committee Members:
  • Gregory Ray Ziegler, Thesis Advisor
  • John Neil Coupland, Thesis Advisor
  • Ramaswamy C Anantheswaran, Thesis Advisor
Keywords:
  • Elasticity
  • eye size
  • tef
  • injera
  • viscosity
  • sodium metabisulfite
Abstract:
Injera is a fermented and naturally-leavened flatbread indigenous to Ethiopia. It constitutes 70% of the diet of Ethiopians and is preferably made from the grain of Eragrostis tef. Elasticity and eye (pore) formation are important quality attributes of injera. The pliability of injera allows it to be used as a utensil to pick up wot (stew eaten with injera). The honey-comb like eyes help in the grasping of wot which soaks into the pores on the surface of injera. This study focused on determining the effects of fermentation time and viscosity on the elasticity and eye formation of injera and also understanding the mechanism by which eyes form. Viscosity and fermentation time were found to have a significant effect on elasticity and eye formation of injera. It was observed that injera baked from tef batters with low or high apparent viscosities had fewer eyes on their surfaces and hence an optimum range of apparent viscosity for baking injera with many evenly distributed eyes was determined to be approximately 1.1 to 1.4 Pa.s. Carbon dioxide was also shown to significantly influence the formation of eyes on the surface of injera. The higher the amount of CO2 or gas bubbles in the fermented batter, the higher the number of eyes formed on the injera. Also, addition of sodium metabisulphite (a reducing agent) to tef batters significantly affected both elasticity and eye formation of injera. This suggested that disulfide bonds between proteins may contribute to elasticity and may have an influence on eye formation.