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Citation Information

Type Journal Article - African Journal of Food, Agriculture, Nutrition and Development
Title Improvement of Injera shelf life through the use of chemical preservatives
Author(s)
Volume 12
Issue 5
Publication (Day/Month/Year) 2012
Page numbers 6409-6423
URL http://www.ajol.info/index.php/ajfand/article/download/80469/70718
Abstract
Mould spoilage is a serious problem that affects the shelf life of injera, the staple
Ethiopian fermented bread. Injera is made from teff (Eragrostis tef) but other cereals
may also be used in combination with teff. About two-third of Ethiopian diet consists
of injera and it accounts for about two-thirds of the daily protein intake of the
Ethiopian population. Injera has a high nutritional value, as it is rich in calcium and
iron. Unfortunately, injera has a shelf life of only 3-4 days essentially due to mould
spoilage. The use of weak organic acid as preservative is allowed in acidic foods,
primarily as mould inhibitors. In this study, the effect of chemical preservatives such
as benzoic acid, sodium benzoate, potassium sorbate and calcium propionate were
investigated to prolong shelf life of injera. The preservatives were added immediately
before baking at the concentration of 0.1% of benzoic acid, 0.1% sodium benzoate,
0.2% of potassium sorbate, 0.3% of calcium propionate and 0.2% blend of the four as
recommended by Food and Drug Administration of USA. Three fungal species:
Aspergillus niger, Penicillium sp and Rhizopus sp were found to be responsible for
injera spoilage. Penicillium and Rhizopus were more dominant at storage temperature
of between 16-200
C, while Aspergillus niger was found to be more dominant at higher
temperature of 25-320
C. Injera samples had a pH and moisture content between 3.38-
3.45 and 62-65%, respectively. Anti-fungal activities of the preservatives investigated
significantly prolonged the shelf life of injera for up to12 days. It was found out that
the effectiveness of preservation was ranked as sodium benzoate>benzoic
acid>potassium sorbate>blend>calcium propionate showing that benzoate and
benzoic acid are the most effective. The outcome of the research has a significant
implication in food security, energy utilization and a significant reduction in the
amount of time used by women to produce injera.

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