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B. Munkh-Erdene, N. Tsevegsuren, G. Davaakhuu. Study on biochemical and phytochemical composition of oats (Avena sativa)
УДК 582.31
STUDY ON BIOCHEMICAL AND PHYTOCHEMICAL COMPOSITION OF OATS (AVENA SATIVA)
© B. Munkh-Erdene
New Medicine Medical Institute © N. Tsevegsuren
Division of natural science, School of Arts and Sciences, National University of Mongolia © G. Davaakhuu
Division of natural science, School of Arts and Sciences, National University of Mongolia E-mail: Munkh-Erdene@ncm.edu.mn
Oats (Avena sativa) are a type of cereal grain. Oats are an important health benefits for human consumption and has relatively higher protein and healthy fats, and lower in carbohydrates compared to other cereals. Oats help to remove cholesterol from the cardiac blood flow to prevent thrombus, to normalize metabolism, to immune-stimulate, to activate thyroid gland and to eject toxic substance. Numerous studies have shown that oat polyphenols had antioxidant properties but no data are available for similar activity on proteins and peptides. Keywords: oats, hydrolysate, DPPH method.
Method
Determining basic biochemical components of oats by standard methods and contents of total saponins and flavonoids by spectrophotometry analysis. Determining of macro and micro elements by XRF analysis, isolated of glucan polysaccharide and total protein. Preparation of protein isolated.
Trypsic digestion of protein: Trypsin hydrolysis of protein was performed similar to the method with the following modifications. Freeze dried protein isolate (300 mg) was suspended in 20 ml Milli-Q water at pH 8.0 and 5.5 mg of trypsin (enzyme/substrate ratio 1:50 w/w) were added. Incubation was carried out at 37°C with shaking (LSI-100B) for 20 h. The reaction mixture was then heated at 90°C for 10 min to inactivate the enzyme. The tryptic digested samples were centrifuged (MLW T54) at 5000 x g for 15 min.
Determination of scavenging effect on DPPH radical: The absorbance at 517 nm was measured using a spectrophotometer against a blank of 100 % methanol. DPPH is a relatively stable radical that is widely used to test the ability of compounds to scavenge free radicals and therefore act as antioxidants. DPPH solution was prepared adding of dry 43mg DPPH in to 3.3ml methanol. 300ц! from the solution were mixed with 2700ц! methanol. First sample was prepared by mixing of 100^,l from the original sample of hydrolysates with 1000ц! methanol. 50ц! from first sample were mixed with 3100ц! methanol and 150ц1 DPPH.
All DPPH tests were carried out in triplicate and the antioxidant activity was calculated as follows: Scavenging effect ( %),
% = ii--r4>-100
where, A, was the absorbance at time t and ACtL the absorbance of control (DPPH) at time zero.
Results and Discussion
Weight of 1000 seeds was 56.9 g, weight of oats without hulls was 39.4g. We are isolated 69.6g beta-glucan, 35.4g total protein, which contain 80.2 % protein from 1500g oats. And 0.47 % albumin, 1.99 % avenalin, 1.58 % avenin and 2.04 % glutelin were isolated from 100g oats.
We have investigated the antioxidant activity of hydrolysates from total oat proteins by (2,2 — Diphenyl-1-picrylhydrazyl) DPPH method. DPPH is a relatively stable radical that is widely used to test the ability of compounds to scavenge free radicals and therefore act as antioxidants. Antioxidant activity of protein fractions was shown in figure 1.
ВЕСТНИК БУРЯТСКОГО ГОСУДАРСТВЕННОГО УНИВЕРСИТЕТА
2015. Вып. 12
С Uli nil)
■ Älibumin
■ Avcnalin Avenin
-Gkitelin
-+— Tocopherol
Figure 1. Antioxidant activity of trypsic digests protein fractions and tocopherol
Antioxidant activities of trypsin digests of oat protein fractions were determined by DPPH method to be 39.2 % in avenalin, 23.5 % in avenin and 8.8 % glutelin at concentration (80 ^.l/ml) and 36 % in albumin at concentration 40 ^.l/ml.
References
1. Tsopmo A., Cooper A. and Jodayree S. Enzymatic Hydrolysis of Oat Flour Protein Isolates to Enhance Antioxidative Properties. Advance Journal of Food Science and Technology. 2010. No. 2(4). Pp. 206-212.
