Byproducts Utilization from Wheat Milling Industries for Development of Value Added Products

Type Thesis or Dissertation - Master Thesis
Title Byproducts Utilization from Wheat Milling Industries for Development of Value Added Products
Author(s)
Publication (Day/Month/Year) 2014
URL http://etd.aau.edu.et/bitstream/123456789/6286/1/Yemsrach Yishak.pdf
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.

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