IMPROVEMENT OF SHELF LIFE OF 'INJERA' USING CHEMICAL PRESERVATIVES

Injera is staple Ethiopian fermented bread which can be made from different types of cereals,
particularly from tef (Eragrostis tef). About two-third of Ethiopian diet consists of injera and it
accounts for about two-third of the daily protein intake of Ethiopian population. It has a very
high nutritional value, as it is rich in calcium and iron. Unfortunately, injera has a short shelf
life of 3-4 days essentially due to mould spoilage. The use of weak organic acid as
preservatives is allowed in acidic foods, primarily as mould inhibitor. In this study, the
influence of some commonly used chemical preservatives, benzoic acid, sodium benzoate,
potassium sorbate and calcium propionate was investigated by isolation of moulds before and
during its ambient storage for 12 days. The preservatives were added immediately before
baking at the concentration of 0.1% of benzoic acid/ sodium benzoate, 0.2 % of potassium
sorbate, 0.3 % of calcium propionate and 0. 2 % blend of the four (wt/wt) as recommended by
Food and Drug Administration. Three fungal species: Aspergillus niger, Penicillium sp and
Rhizopus sp found to be responsible in injera spoilage. Penicillium and Rhizopus are more
dominant at the temperature of between 16-200c, while Aspergillus niger is more dominant at
higher temperature of between 25-320c. Injera samples had a pH and moisture content of 3.38-
3.45 and 62-65%, respectively