Effect of Refined Milling on the Nutritional Value and Antioxidant Capacity of Wheat types Common in Ethiopia: A Recovery Attempt with Bran Supplement
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Date
2014-06
Authors
Gebremedhin, Genet
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Publisher
Addis Ababa University
Abstract
The effect of wheat flour extraction on nutritional quality of two types of wheat grown in
Ethiopia ( hard and soft) was evaluated. Whole wheat flour (lOO% extraction) and white wheat
flour (68% extraction) were subjected to proximate, mineral and antioxidant analysis. Results
indicated that at low extraction rate (68 %) the value of protein, fat, jibeI', ash, Iron, zinc and
phmphorous and antioxidant content of the samples were significantly affected (decreased)
(P< 0.05) by milling. The total phenolic content (TPC) of white wheatjlours, which rangedji-om
3.34 to 3.49 mg CAE/g were significantly lower (p<0.005) than those of whole wheat flours
(range 7.66 to 8.20 CAE/g). At the concentration of 50 mg/mL used, the scavenging effect of
wheat extracts, on the DP PH radical scavenging decreased in the order of soft whole, hard
whole, sofl white and hard while wheat flour, which were 90.39, 89.89, 75.80, 57.57%,
respectively. Bread was prepared from different levels of substitution of white wheat jlour by 0 to
25 % of wheat bran. The proximate composition, mineral content and sensory properties of the
bread were investigated. The results indicated that protein, fat, ash, jiber, iron and zinc contents
of the bran supplemented breads increased significantly (P<0.05) with the progressive increase
in the bran level of the bread. The highest value for protein, fat, jiber ,ash, iron and zinc was
12.04,2.61,2.48,3.27 g/100g and 4.84 and 2.33 mg/IOOg respectively were found in 25 % bran
supplemented bread. The sensory evaluation of bread showed that all level of supplemenlalion
had mean score above 4 on over all acceptances. The results indicated that rejined milling at
68% extraction significantly reduce the nutritional and antioxidant activity of wheat flour and
Bread of good nutritional and sensory qualities could be produced from 10 % and 20 % bran
supplementat ion.
Key words: Whole wheat flour, white flour, bran, extraction rate, free radical scavenging
activity.
Description
Keywords
Whole wheat flour, white flour, bran, extraction rate, free radical scavenging activity