Effect of Processing and Tef Varieties (Eragrostis Tef (Zucc.)) on the Antioxidant Properties of Ethiopian Traditional Bread, Injera
No Thumbnail Available
Date
2012-05
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Imbalanccd product ion and consumption of reactive oxygen species, reading to oxidative
stress such as cancer, arteriosclerosis neu rodegenerative diseases and ageing processes. The
protect ive effects of plants have long been attributed to their ant ioxidant compounds, such as
phenolic compounds and flavono ids. The purpose of th is study was comparing antioxidat ive
potenti"! of methanolic extracts of three tef varieties (white. brown and red tel) and the ir
injeras (partly ferm ented and fu lly fermented) and their enriched one with fen ugreek. The
antioxidant capacities of tef varieties and the ir flat bread, iI?jeras were evaluated by using
different methods, name ly DPPH (2. 2-diphenyl-I-picryl hydrazyl) free radical scavenging
activ ity, total reduc ing power. IOta I phenol contents and total flavo noid levels. Total phenol
content (TPC) was determined by using folin-ciocalteau reagent. Total tlavonoid content
(TFC) was determined by using colorimetric assay method, the absorbance of all parameters
measured using UV-viz-spectropholOmetry. The level of Ie 50 values of free radical and total
reducing power of various tefvarieties varied from 0.6 IlIg/ml to 0.88 mg.1 ml and 2.25 111g111l1
10 2.5 mg/ml respectively. The results Showed the highest scavenging activities (0.6 mg/ml)
and reducing power (2 .25 mglm l ) observed in red tef while the lowest scavenging activities
and reductive potential potent in white tef ( 0.86 mg/ml) and (2.5g1mi). Current results of
lotal phenolic content assay indicate that total phellol co ntent was higher in red tef(II.47 mg
GAE/g) as compared to brown (9.715 mg GAE/g) and white tef (8.28 mgl GAE/g). In
addition: total tlavonoids for white, brown and red tef were 1.03 mg/CE/g. 1.78 mg CE/g and
2. 13 mg CE/g respective ly. The processing of tef flour ill to partly or fully fermented illjeras
and their enrichment with fenugreek affect the lef antioxidant levels th:s has imp lications for
the ir bioactive properties a nd pote nti al health bcnclits. The IC;o - values i'or free radical
scavenging activit ies and reduc ing power of pa rtly fermented, fully fenncnted, c nriched
partly tcnnented and enriched fully fermented white td' ily'eras were 2.8 111 g11ll1 ; 2.75 Illg/ml.
3.25 mglml ; 3.3 lng/m!. 2.63 mg/ml; 2.7 mglml ; 3 lll glmi ; 3 mg/m! respectively. Phenolic
compos ition in the lef injeras examincd. The results showed that enriched partly fermented
red tel' illjeras had remarkable phenol levds (ur to 9.12 GAE/g). The lotal phenol contents
lor partly fermented , hilly fermented, and enriched fully fermented red tef injerus we re found
lO be g.75. 7.36, and 8.24 mg GAE/g respectively. In brown I.efinjeras. the highest fla vonoid
,:Oittcnl was noticed in enriched partly fermented ily'era (1.9 mg eEl g).
Description
Keywords
Effect of Processing