Inst of Food Technology in Novi Sad, Univ of Novi Sad, Bulevar cara Lazara 1, 21000 Novi Sad, Serbia.
J Food Sci. 2012 Sep;77(9):C954-9. doi: 10.1111/j.1750-3841.2012.02867.x. Epub 2012 Aug 13.
Buckwheat (Fagopyrum esculentum Moench) is an alternative crop belonging to the Polygonaceae family. In comparison to antioxidant activity of frequently used cereals, buckwheat has been reported to possess higher antioxidant activity (AOA), mainly due to high rutin content. The objective of this work was to determine the main antioxidant compounds and AOA of buckwheat grain fractions (whole grain, hull, and groat). Buckwheat grain fractions were extracted with ethanol/water (80/20, v/v), followed by determination of total phenolic and flavonoid content. Quantification of phenolic compounds and tocopherols was performed by high-performance liquid chromatography (HPLC). The AOA was estimated by 2 direct electron spin resonance (ESR) and 4 indirect (spectrophotometric) tests. Significantly higher contents of total phenolics and total flavonoids were found in buckwheat hull than in whole grain and groat. Protocatechuic, syringic, and sinapic acid, rutin, and quercetin were found in all tested fractions, whereas vanilic acid was found in whole grain and hull. The content of total tocopherols in investigated samples ranged from 23.3 mmol/g for hull to 61.8 mmol/g for groat. Hull was superior in scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)), hydroxyl ((•)OH), and superoxide anion (O(2)(•-)) radicals, reducing activity, AOA by β-carotene bleaching method, and chelating activity on Fe(2+) as evidenced by its lower IC(50) value. Obtained results can broaden the utilization of buckwheat, especially a share of hull in whole grain flour production.
Obtained results suggest possibility to supplement the whole grain buckwheat flour with hull, which leads toward better usage of by-products in buckwheat production, and enhancement of antioxidant potential of the final product.
荞麦（Fagopyrum esculentum Moench）是一种属于蓼科的替代作物。与经常使用的谷物的抗氧化活性相比，荞麦被报道具有更高的抗氧化活性（AOA），主要是由于芦丁含量高。本工作的目的是确定荞麦籽粒各部分（全谷物、外壳和麦粒）的主要抗氧化化合物和 AOA。用乙醇/水（80/20，v/v）提取荞麦籽粒各部分，然后测定总酚和类黄酮含量。用高效液相色谱法（HPLC）定量测定酚类化合物和生育酚。用 2 种直接电子自旋共振（ESR）和 4 种间接（分光光度法）试验测定 AOA。荞麦壳中的总酚和总类黄酮含量明显高于全谷物和麦粒。在所有测试的部分中都发现了原儿茶酸、丁香酸和芥子酸、芦丁和槲皮素，而香草酸仅存在于全谷物和外壳中。在所研究的样品中，总生育酚的含量范围从外壳的 23.3mmol/g 到麦粒的 61.8mmol/g。荞麦壳在清除 1,1-二苯基-2-苦基肼（DPPH(•)）、羟基（（•）OH）和超氧阴离子（O(2)(•-））自由基、还原活性、β-胡萝卜素漂白法的 AOA 和对 Fe(2+)的螯合活性方面均优于其他部分，这表明其 IC(50)值较低。研究结果可以拓宽荞麦的用途，特别是在全谷物面粉生产中添加荞麦壳。
