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استخلاص مضادات الاكسدة بمساعدة الموجات الدقيقة من اليرون حبة القمح وجنينها ونخالتها ودراسة تاثيرها في الصفات الريولوجية للعجين == Extraction of Antioxidant with Assisted Microwave from Aleuron Wheat Grain, Germ and Bran and Study its Impact in the Rheological Properties of Dough
Author name:
علاء محمد صالح مجيد المسافر
Supervisor name:
علي احمد ساهي | علي خضير جابر الركابي
General topic:
Agricultural sciences
Specific topic:
Food
Degree:
Doctorate
University:
University Of Basrah - Faculty Of Agriculture
Language:
Arabic
University location:
Basrah
First pages:
31T1833 - p.pdf
Abstract:
This study was conducted to investigate and test the activity of three essential parts of wheat seed Aleurone, germ and bran which were used as secondary products from grinding grain to feed animals. diversity solvents (distilled water, chloroform, hexane, ethanol, methanol) were applied to extract the bioactive compounds by both traditional and modern extractions.The total phenolic compounds, antioxidant activity, reducing power, metal chelating, and scavenging of hydrogen peroxidase were determined for all three essential parts of wheat. The stability of the extracts was studied toward temperature and pH at the interval time. In addition, the synergistic effect of the extracts was studied by mixing with different concentrations of ascorbic acid and alpha tocopherol. The extracted compounds were identified using gas chromatography mass spectroscopy (GC - Mass).The ethanol extraction of wheat germ had the highest antioxidant activity, so it was chosen to prevent oxidation in the corn oil. Moreover, the ethanol extractions for germ, bran and Aleurone were added to wheat flour (80 % extraction) in order to study their effects as improvers in the rheological properties of wheat flour dough. The results were as follows : 1 - The microwave - assisted extraction for 40 sec was able to extract the highest level of phenolic compounds from wheat germ compared toconventional extraction conditions. The total phenolic compounds were 556.6 μg gallic/ml, 426 μg gallic/ml for ethanol and methanol extractions, respectively.2 - The microwave - assisted extraction was able to give the highest antioxidant activity (53%) at concentration of 100 mg/ml from ethanolic wheat germ extraction compared to synthetic antioxidant BHT ( 92 %). In addition, the wheat germ had the highest reducing power (163.88 %) at concentration of 5 mg/ml , while the percentage of reducing power for both ethanolic extraction of Aleurone and ethanolic extraction of wheat bran were 112.63 % and 79.68 %, respectively. In contrasts, all of above extractions had lowest reducing power compared to BHT and alpha tocopherol 249.8 % and 223.5 % respectively at the same concentration. Moreover, the wheat Grem had the highest percentage for both Ferrous chelating and scavenging of hydrogen peroxidase.3 - Ethanolic extracts of Aleurone, bran and germ have a higher antioxidant activity in natural pH while decreased when treated with acid and alkaline. In addition, the ethanolic wheat germ was able to give the highest antioxidant activity at 100°C for 100 min wich read 62.2% compared to others and gave synergistic effect for bothascorbic acid and alpha tocopherol exhibited 91.90 % of antioxidant activity at concentration 60 mg/ml.4 - Identification of ethanolic and methanolic extract using GC/MS showed presence of bioactive compounds such as ascorbic acid, benzoic acid, phytosterol compounds, Isoeugenol and alkylresorcinols5 - Ethanolic extracts of germ with concentration 0.05, 0.10, 0.15, 0.20, 0.25 mg/g was added to corn oil in order to compared with BHT 0.05% and stored at 45°C for 28 days, the result showed that the ethanolic wheat germ at 0.25 mg/g had the ability to decrease the hydrogen peroxide for the corn oil 6.8 meq/kg at end of stored time compared BHT (0.05 %) 4.3 meq/kg at the same conditions.6 - The ethanolic Aleurone extraction possessed a positive effect on the rheological properties when it was added as improvers to the wheat flour ( 80 % extraction). The dough consistency was 6.7 min, which considered highest reading among all treatments. In addition, the recorded elastic index was 3.2, 2, and 1.8 at interval times 45, 90, 135 min, respectively.
