不同品种大豆异黄酮组分及体外抗氧化活性分析

为研究不同品种大豆异黄酮组分和含量以及抗氧化活性，测定了50个特色大豆品种的百粒重、色泽（L*、a*、b*），通过高效液相色谱法（HPLC）测定异黄酮组分，评估不同品种大豆甲醇提取物的DPPH、ABTS自由基清除能力，并用相关性分析、主成分分析及聚类分析法对样品进行分析。结果表明:大豆的百粒重范围为7.05~47.46 g。不同种皮色大豆L*、a*和b*呈现显著差异（P<0.05）。HPLC分析结果发现糖苷型异黄酮含量是大豆中主要的异黄酮组分，占总异黄酮含量的90%以上。其中染料木苷含量最高。安豆115品种的大豆异黄酮的总含量最高，为2500.78 μg/g；靖江丝瓜青品种的大豆异黄酮含量最低，为888.86 μg/g。安豆115品种的DPPH和ABTS自由基清除能力较强，分别为（16.11±0.25）和（8.12±0.04）μmol V_C/g。糖苷型异黄酮含量与DPPH和ABTS自由基清除能力有较高的线性相关性（R2分别为0.903和0.867）。主成分分析表明6项指标可用2个主成分来表示（累计贡献率达66.3%）。聚类分析将50个品种的大豆分为4类:第一类中黄豆黄素和黄豆黄苷含量较高；第二类中大豆苷、大豆苷元、染料木苷和染料木素含量较高；第三类和第四类中其大豆异黄酮含量基本处于中等水平和较低含量。综上所述，不同大豆品种的异黄酮组成、含量和抗氧化能力存在较大差异，可为其进一步综合开发利用提供一定理论基础。

Analysis on the Isoflavone Profile and Antioxidant Activity in Vitro of Different Soybean Varieties

In order to study the components and content of soybean isoflavones and antioxidant activity of different varieties of soybeans, hundred kernel weight and seed coat color of 50 soybean varieties were measured. High performance liquid chromatography (HPLC) was used to determine the components of isoflavone. DPPH and ABTS radical scavenging activities were used as indicators to evaluate the antioxidative activity of soybean methanol extract. Samples were analyzed by correlation analysis, principal component and cluster analysis methods. The results showed that the hundred kernel weight ranged from 7.05~47.46 g. L*, a* and b* of soybeans with different seed coat color showed significant differences (P<0.05). Results of HPLC revealed that the glycosidic isoflavone was the main isoflavone component in soybean, accounting for more than 90% of the total isoflavone. The content of genistin was the highest. The Andou 115 variety exhibited the highest isoflavone content, which was 2500.78 μg/g. Meanwhile, the Jingjiang loofah green variety has the lowest content of soy isoflavones at 888.86 μg/g. The DPPH and ABTS radical scavenging activities values of Andou 115 varieties were relatively high, which reached (16.11±0.25) and (8.12±0.04) μmol V_C/g, respectively. The content of glycosidic isoflavone had a high linear correlation with DPPH and ABTS radical scavenging activities (R2 was 0.903 and 0.867 respectively). Principal component analysis showed that 6 indicators could be represented by 2 principal components (cumulative contribution rate reaches 66.3%). Cluster analysis divides 50 kinds of soybeans into 4 categories: The first category gathered higher content of glycitein and glycitin. The second category gathered high content of daidzin, daidzein, genistin and genistein. The third and fourth categories gathered varieties with medium level isoflavone and low isoflavone content respectively. The isoflavone composition and content and antioxidant activity of different soybean varieties are significant different. The results can provide a theoretical basis for the comprehensive development and utilization of soybeans.