D301阴离子交换树脂对大豆异黄酮分离特性的影响

为更好地将离子交换树脂应用于大豆异黄酮的分离纯化,研究了乙醇含量、pH、温度、初始浓度等条件对D301阴离子交换树脂吸附分离大豆异黄酮的影响。静态吸附实验结果表明,该树脂在以水为溶剂、pH 8左右、40℃时对大豆异黄酮有最好的吸附效果。穿透曲线实验表明,动态饱和吸附量受温度影响较大,当柱温为50℃、初始浓度C07.03 mg/mL时,饱和吸附量为105.0 mg/g干树脂。洗脱曲线实验表明,采用体积分数75%乙醇洗脱,异黄酮回收率为89.3%,产品中大豆异黄酮含量高达56.0%,含量比原料提高了十几倍。表明D301阴离子交换树脂对大豆异黄酮的分离纯化具有较好的选择性和应用前景。     

豆粕中大豆异黄酮提取工艺的优化

采用乙醇回流浸提和HCl水解两步法，从大豆豆粕中提取大豆异黄酮类化合物，以染料木素为标准物，在紫外区对异黄酮含量进行测定。通过正交试验确定最佳提取工艺。本实验平均回收率为95．7％。     

中国大豆制品中异黄酮含量测定和分析研究

对中国几种有代表性的大豆制品进行了异黄酮含量测定。测定结果表明 :中国的大豆制品中含有一定量的异黄酮 ,其中非发酵制品中的异黄酮只有极少量以游离形式存在 ,大部分以 β 葡萄糖苷的形式存在 ,主要是黄豆苷 (daidzin)和染料木素 (genistin) ;而在发酵大豆制品中 ,由于酶的作用 ,部分黄豆苷和染料木素转化成黄豆苷原 (daidzein)和染料木因 (genis tein) ,因此 ,游离态的异黄酮比例增加。中国大豆制品中异黄酮含量随大豆品种和加工工艺而异 ,含量范围在 1 1 2 82～ 1 871 6 1 μg/ g ,这个结果表明中国的大豆制品对人体的健康具有重要作用。     

豆类食品中4种大豆异黄酮的含量分析

检测并评估市场上主要豆类食品中大豆异黄酮的含量,进一步补充和完善大豆异黄酮含量数据库.选购日常豆类食品11类,共计51个样品,对样品进行真空干燥、正己烷脱脂、80％甲醇提取处理后,采用高效液相色谱法对其中的4种大豆异黄酮、染料木素、染料木苷、大豆苷元、大豆苷进行检测和分析.结果显示:豆干类为所选样品中大豆异黄酮含量最多的食品,平均含量＞600μg/g,嫩豆腐、油豆腐、黄豆芽、绿豆芽、豆浆粉和腐乳类样品中大豆异黄酮含量范围100～600μg/g,豆浆类＜100 μg/mL,豆奶粉类＜100 μg/g,酱油和绿豆糕类样品中异黄酮含量低于检出限;腐乳类样品中苷元比例较高,说明该类食品中雌激素样活性成分比例较高.推断豆干、腐乳类食品的长期过度摄入,可能会引发较为明显的雌激素样生物效应.     

四种异黄酮抗氧化活性的比较研究

植物异黄酮类雌激素是目前研究较多的一类天然活性物质.本实验通过对不同浓度的四种异黄酮溶液的羟自由基清除实验、超氧阴离子自由基清除实验及对猪油的抗氧化实验,比较并确定了各种不同结构的异黄酮的抗氧化能力及其与内在化学结构的关系.通过实验发现,染料木黄酮的抗氧化能力最高,而芒柄花黄素的抗氧化活性最低.这可能是由于它们含有的羟基个数及所在化学结构中羟基位置不同而造成的.     

Red clover (Trifolium pratense L.) isoflavones: determination of concentrations by plant stage,flower colour,plant part and cultivar

BACKGROUND: Red clover (Trifolium pratense L.), a widely used fodder, has recently received considerable interest as a valuable source of isoflavones for many health‐related applications. The aim of this study was to analyse the concentrations of four isoflavones, daidzein, genistein, formononetin and biochanin A, in extracts of leaves, stems, roots and different coloured flowers from red clover by high‐performance liquid chromatography and to determine the antifungal activities of the extracts. RESULTS: Among greenhouse‐grown samples the highest amounts of daidzein and genistein were found in petioles (0.11–0.28 and 0.30–0.54 mg g^?1 respectively), while leaves were rich in formononetin and biochanin A (5.57–9.05 and 10.94–14.59 mg g^?1 respectively). High formononetin concentrations were found in roots, but very little biochanin A. Among field‐grown samples the highest concentrations of daidzein and genistein were detected in stems collected in August (0.24 and 0.55 mg g^?1 respectively), while the highest amounts of formononetin and biochanin A were found in young leaves collected in June (7.47 and 9.69 mg g^?1 respectively). Most of the extracts inhibited the growth of Drechslera teres, while the root extract showed the strongest effect against Microdochium nivale. CONCLUSION: High levels of bioactive compounds found not only in inflorescences but also in roots, leaves and stems suggest that red clover may be an inexpensive and valuable resource for many applications. Copyright © 2007 Society of Chemical Industry     

Effect of temperature and water availability during late maturation of the soybean seed on germ and cotyledon isoflavone content and composition

BACKGROUND: Isoflavone content in soybean seeds is strongly influenced by both environment and genotype. However, little is known about the effect of environment and genotype on isoflavones in germ versus cotyledons. To determine the effect of temperature and soil moisture status during soybean seed development on seed isoflavone concentration and composition, a set of two French and three US cultivars of similar maturity were grown in the greenhouse. At the R6 growth stage, plants were subjected to one of three night/day temperature regimes (13/23°, 18/28° or 23/33 °C) in either optimal or sub‐optimal soil water conditions. RESULTS: In cotyledons, a three‐ to six‐fold variation in total isoflavone content was observed between the high and low temperature treatments, whereas the germ contents had less than a two‐fold variation. Soil water supply had less effect than temperature on the isoflavone contents and compositions. In both seed parts, the isoflavone concentrations were highly dependent on the cultivar. CONCLUSION: These results show that isoflavone content and composition in cotyledon and germ are unrelated and it should be possible to independently manipulate these seed traits through plant breeding and crop management systems. Copyright © 2007 Society of Chemical Industry     

红车轴草不同部位中异黄酮含量的测定

采用反相高效液相色谱法对红车轴草不同部位(花、茎和叶)中四种主要异黄酮(鸡豆黄素A、芒柄花黄素、染料木素和大豆黄素)的含量进行了测定,结果表明:以占干物质计,4种异黄酮总量,叶中含量最高(0.856%),茎次之(0.403%),花中含量较低(0.258%)。鸡豆黄素A和芒柄花黄素是红车轴草中两种最主要的异黄酮,主要分布在叶中,其次是茎,花中含量较低。染料木素和大豆黄素,无论是花、茎还是叶,含量均较低。     

三波长紫外分光光度法测定红车轴草异黄酮含量的研究

红车轴草乙醇提取液，颜色较深，背景吸收较大，以一般常用的单波长紫外分光光度法测定红车轴草异黄酮含量时，色素和醇溶性蛋白等杂质干扰严重。本文建立的三波长紫外分光光度法，能有效扣除色素和醇溶性蛋白等杂质的干扰，精密度实验的相对标准偏差为0．85％，平均加样回收率为103．95％，加样回收率的相对标准偏差为1．82％。本方法具有简便、快速、准确等特点。     

高效液相色谱法测定纳豆及纳豆胶囊中的大豆异黄酮含量

建立了纳豆及纳豆胶囊中大豆异黄酮的高效液相色谱分析方法,该方法重复性及样品稳定性良好.实验对原料黄豆、纳豆和纳豆胶囊样品采用石油醚索氏脱脂后,对固体样品进行乙醇回流提取,分析了4种大豆异黄酮组分,即大豆苷、染料木苷、大豆素和染料木素.结果表明,原料黄豆总异黄酮质量比为1 260 mg/kg,纳豆比原料黄豆总异黄酮含量明显高约30%,纳豆胶囊比原料黄豆总异黄酮含量高约11%.