engleski

Optimization of extraction conditions for determination of radical scavenging activity in amaranth

Amaranth is one of the few non-grasses broad-leafed plants that produce significant amount of edible 'cereallike' grain crop. In addition to its high protein and iron content and its nutritional excellence among other pseudo grains and grains, amaranth’s antioxidant potential has stayed unrevealed. Due to a variety of antioxidant extraction procedures in the literature, and a lack of optimized extraction method for amaranth, the main goal of this investigation was to determine the impact of different extraction conditions on extracting efficacy. Antioxidant potential from collected amaranth extracts was evaluated using Oxygen Radical Absorbance Capacity (ORAC- FL) assay which measures antioxidant activity by maintaining the kinetics of fluorescence loss and uses area under the curve for its quantification. Among all investigated reaction mixtures acidified 30 % methanol extract (pH 1.4) reached the highest ORAC- FL activity. Observed shape and decay of the amaranth’s methanol sample curve showed similarity to the previously published ORAC-FL curves of pure phenolic compounds. Therefore, Folin-Ciocalteu colorimetric analysis was additionally preformed. Total phenolics content was determined in all investigated extracts and obtained values were correlated with ORAC activity. Significant, but week positive correlation was found, suggesting that other non- phenolic compounds play significant role in amaranth’s antioxidant defense (r = 0.5338, p = 0.0404). Extracts obtained using optimized extraction conditions showed high antioxidant capacity measured by ORAC-FL and high total phenolic content (275.39 μmol TE/g and 150, 47 mg FA/100g, respectively) suggesting amaranth grain and its extract as an important antioxidant research material in pharmaceutical and nutritional field.

solvent extraction; antioxidant activity; ORAC- FL; amaranth

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