【作者】 何永艳；

【导师】 冯佰利；

【作者基本信息】 西北农林科技大学 ， 植物资源学， 2008， 硕士

【摘要】 荞麦营养丰富,医食同源,是现代功能型食品开发的重要资源,在国内外市场上具有较强的竞争力,特别是我国加入WTO后,大宗谷物国际市场走势下降,荞麦及杂粮市场出现强劲势头。目前由于对化学抗氧化添加剂成本的考虑,寻求新的高效低毒的天然食品抗氧化剂成为了研究的热点。荞麦在中国乃至世界上都是最重要的植物之一,从荞麦及其衍生物中开发出具有抗氧化活性的物质,不仅来源广泛,成本低,而且安全性高,消费者容易接受。然而,荞麦科研起步较晚,基础性研究比较薄弱,对荞麦中有效成分研究还不够深入,尤其是对某种特定有效成分的药理作用研究还比较少见,这是荞麦现代化进程中急需解决的问题。本文以荞麦为原料,采用微波辅助法提取荞麦中的酚类化合物。并分析测定了荞麦中乙醇提取物的总酚含量、黄酮含量、总抗氧化活性和对二苯代苦味酰基自由基(DPPH)?、羟基自由基(?HO)、超氧自由基(O2-?)的清除作用。得出如下主要结论:(1)通过对参加国家荞麦品种区域试验的17个品种进行研究发现,不同类型荞麦品种种子乙醇提取物中酚类物质、类黄酮物质含量和总抗氧化活性(FRAP值)存在较大差异,而同一类型不同品种荞麦之间差异较小。苦荞粉总酚含量、总抗氧化活性(FRAP值)均高于甜荞,约是甜荞的2-3倍;而甜荞皮壳总酚含量、黄酮含量和总抗氧化活性(FRAP值)均高于苦荞,且两者相差较大,甜荞约是苦荞的2倍。(2)对5个荞麦面粉提取物抗氧化活性研究表明,苦荞总酚含量和黄酮含量是甜荞的2倍,总酚含量和黄酮含量最高的是西农9909,分别为268.73±5.03mg/g,59.57±9.56mg/g。苦荞的FRAP值(总抗氧化活性)是甜荞的3倍,总抗氧化性最高的是九江苦荞,其FRAP值为2.54±0.38 mmol/100g。西农9909对DPPH·自由基、·OH自由基和O2-·自由基的清除作用最大,其IC50值分别为43.25mg/L、0.24mg/ml和0.12mg/ml。(3)对5个荞麦皮壳提取物抗氧化活性研究结果可以看出,苦荞较甜荞低,总酚含量和黄酮含量最高的是榆荞-4,分别为336.73±12.03mg/g,121.30±2.73mg/g,总抗氧化性最高的是榆荞-4,FRAP值为1.55±0.13 mmol/100g。榆荞-4对DPPH·自由基和·OH自由基的清除作用最大,其IC50值分别为13.97mg/L和0.38mg/ml;西农9976对O2-·自由基的清除作用最大,其IC50值为0.13mg/ml。(4)对5个荞麦芽苗提取物抗氧化活性研究结果可以看出,苦荞中总酚含量和黄酮含量是甜荞的2倍,荞麦乙醇提取物中总酚含量最高的是西农9909,为322.26±3.79mg,黄酮含量最高的是九江苦荞,为60.77±5.22mg,苦荞的FRAP值(总抗氧化活性)是甜荞的3倍,总抗氧化性最高的是西农9920,其FRAP值为6.82±0.08 mmol/100g。荞麦芽苗乙醇提物中,西农9920对DPPH·自由基的清除率最大,其IC50值为3.23mg/L;九江苦荞对·OH自由基和O2-·自由基的清除率最大,其IC50值分别为88.31mg/L和13.16mg/L。(5)种植地区是荞麦酚类化合物含量及抗氧化活性的主要影响因素之一。通过对不同生态区的荞麦地上部分的研究显示,不同生育期荞麦总酚、黄酮含量及抗氧化活性总体上先升高后降低,但河北张北试点总酚、黄酮含量及抗氧化活性在出芽苗期较高,随着生育期逐渐降低。同一时期苦荞的总酚、黄酮含量和抗氧化活性高于甜荞,表现为西农9920>九江苦荞>平荞2号>榆荞2号。更多还原

【Abstract】 Buckwheat can be served as edibles and medicaments which has rich nutritional value. It has been recognized as important resources of development modern functional food. It has the strong competitive power in the domestic and foreign markets, especially after our country joined WTO, large quantities of grains’trend drops in the foreign market, but the buckwheat and the miscellaneous grains market have the strong tendency. At present, consideration of some chemistry anti-oxidant additives cost, thus seeking the new highly effective and low poisonous natural food oxidation inhibitor becomes the hot spot of research. Buckwheat is one of most important plants in China and even the world. The anti-oxidant activity material develops from the buckwheat and the derivative, not only originates widely, low cost, high security, and consumer accept easily. However, because buckwheat research had a late start, its basic reseach has been very week, the effective component research is not deep, especially in some specific effective component’s pharmacological action research is also quite rare, it has become an urgent problem that need being solved in the buckwheat modernization process. Therefore it have the vital significance of carring on the buckwheat anti-oxidan activity development research.In this paper, phenol compound were extracted from the buckwheat by employing microwave method. The total phenolics and total flavonoids contents, total antioxidant capacities along with ?HO, DPPH?,O2-? radical scavenging ability of buckwheat ethanol extracts were examined. The results showed that:(1) The result indicated that there was great difference in total phenolics and total flavonoids contents, total antioxidant capacities (FRAP value) of ethanol extracts of tartary and common buckwheat seeds, but not remarkable difference in different cultivars of the same type. All of the buckwheat seeds were participated in the national buckwheat variety regional test. Total phenolics contents and total antioxidant capacities (FRAP value) of tartary buckwheat flour was approximately two~three times higher than that of commom buckwheat flour. In contrast, total phenolics and total flavonoids contents, total antioxidant capacities (FRAP value) of commom buckwheat hull was higher than that of tartary buckwheat hull and the differences was significant.(2) Anti-oxidant activity of five kings of buckwheat flour were determined. The result showed that: Total phenolics and total flavonoids contents of tartary buckwheat flour was approximately two times higher than that of commom buckwheat flour and Xinong 9909 was highest, respectively, for 268.73±5.03mg/g, 59.57±9.56mg/g. Total antioxidant capacities (FRAP value) of tartary buckwheat flour was approximately three times higher than that of commom buckwheat flour and Jiujiang tartary buckwheat was highest (2.54±0.38 mmol/100g). Xinong 9909 has the higehest rate of DPPH·radical、Hydroxyl radical and Superoxide anion scavenging ability in the five kinds of buckwheat flour ethanol extracts, and IC50 value were 43.25mg/L, 0.24mg/ml, 0.12mg/ml respectively.(3) Anti-oxidant activity of five kings of buckwheat hull were determined. The result showed that: Total phenolics and total flavonoids contents of commom buckwheat hull was higher than that of tartary buckwheat hull and Yuqiao-4 was highest, respectively, for 336.73±12.03mg/g, 121.30±2.73mg/g. Total antioxidant capacities (FRAP value) of Yuqiao-4 was highest (2.54±0.38 mmol/100g). Yuqiao-4 has the higehest rate of DPPH·radical and Hydroxyl radical ability in the five kinds of buckwheat hull ethanol extracts, and IC50 value were 13.97mg/L, 0.38mg/ml respectively. Xinong 9976 has the highest rate of Superoxide anion scavenging ability and IC50 value was 0.13mg/ml.(4) Anti-oxidant activity of five kings of buckwheat seedling were determined. The result showed that: Total phenolics content of tartary buckwheat seedling was approximately two times higher than that of commom buckwheat seedling and Xinong 9909 was highest (322.26±3.79mg). Total flavonoids content of Jiujiang tartary buckwheat was highest (60.77±5.22mg). Total antioxidant capacities (FRAP value) of tartary buckwheat seedling was approximately three times higher than that of commom buckwheat flour and Xinong 9920 was highest (6.82±0.08 mmol/100g). Xinong 9920 has the higehest rate of DPPH·radical and IC50 value was 3.23mg/l. Jiujiang tartary buckwheat has the highest rate of Hydroxyl radical and Superoxide anion scavenging ability in the five kinds of buckwheat seedling ethanol extracts, and IC50 value were 88.31mg/L, 13.16mg/L respectively.(5) Cultivation area was an influential factor to the phenolic compounds content and anti-oxidant activity. Phenolic compounds contents and anti-oxidant activity of the whole plants above the ground of buckwheat cultivated in different ecological environments were determined. The results showed that the total phenolics and flavonoids content, anti-oxidant activity rose and then declined with the exception of that of plants cultivated in Zhangbei of Hebei which was highest in the seedling stage and declined gradually in the remaining growing stage. Total phenolics and flavonoids contents, anti-oxidant activity of tartary buckwheat was higher than that of commom buckwheat , and in the decreasing order: Xinong 9920>Jiujiang tartary buckwheat>Pingqiao 2>Yuqiao 2.更多还原