Byproducts Utilization from Wheat Milling Industries for Development of Value Added Products
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Date
2014-03
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Addis Ababa University
Abstract
The main byproducts of wheat milling industries, wheat germ and bran, have been known as
an outstanding sources of protein, dietary fiber, trace minerals, antioxidants, phytochemicals
and allied micronutrients. This research was conducted to evaluate utilization of wheat germ
(WG) and wheat bran (WB) for the development of value added cookies and tea substitute
products; respectively. Supercritical fluid extractor (SFE) was used to extract oil from wheat
germ and the defatted wheat germ flour (DWGF) was used as a supplement for wheat flour at
10%, 15% and 20% blending ratios (BR1, BR2 &BR3) and baking temperatures of 150, 180
and 210 oC (T1, T2 &T3).Wheat bran (WB), the other byproduct of wheat milling industries,
used to made tea substitute by milling, screening, and heating before utilized as final product.
Chemical composition of raw materials, physico-chemical and rheological characteristics of
flours were investigated prior to cookies preparation. Proximate analysis for wheat flour
(WF)(0.83,11.92,0.52,0.45,9.33) and defatted wheat germ flour (DWGF) (4.72,
12.98,1.01,5.17,28.11); for ash, moisture, fat, fiber and protein were resulted respectively; as
a result nutrient dense DWGF used as a substitute for development of cookies . It was found
that protein, fiber, ash and minerals (Ca, K, P, and Mg) contents in the blends increased
significantly (P<0.05) with an increase in DWGF substitution. The effect of BR2 and T2 on
proximate composition resulted with (protein (14.29), fiber (2.84), and ash (1.31)) resulted
better together with sensory quality evaluation. Rheological and functional properties of
flours, physical properties for cookies and organoleptic properties for both products were
analyzed. Total phenolic content (TPC) and antioxidant activity were determined by using
Folin-Ciocalteu and DPPH scavenging activity assays respectively. Extraction procedure
went out using methanol at three different temperatures (40, 60 and 80)0C. Higher total
phenolic content ranged from 1.037 to 3.68mg of gallic acid equivalent (GAE)/gm of dried
extract obtained at 60 0C using methanol. While antioxidant activity with lower half maximal
inhibitory concentration (IC50) (mg/ml) value of (1.4, 1.75, 2.13) scavenging activity for
ascorbic acid, methanol solvent extract of wheat bran and by absolute methanol respectively.
Finally, cookies baked at 180oC using blend ratio 15 % resulted better sensory qualification
and wheat bran extracted using solvent methanol at 60oC showed potential antioxidant
activity and TPC.
Keywords: defatted wheat germ, cookies, antioxidant, folin-Ciocalteu assay, DPPH
scavenging capacity assay
Description
Keywords
Defatted Wheat Germ, Cookies, Antioxidant, Folin-Ciocalteu Assay, Dpph Scavenging Capacity Assay