大豆胚芽异黄酮的提取分离与结构鉴定

利用柱层析法从大豆胚芽中分离到 8个异黄酮化合物 ,分别是黄豆素糖苷、大豆苷元糖苷、染料木素糖苷、丙二酰黄豆素糖苷、黄豆素苷元、大豆苷元、染料木素、染料木素葡萄糖苷 - 6″ -阿拉伯糖 ,其中化合物染料木素葡萄糖苷 - 6″ -阿拉伯糖在大豆中为新发现     

热处理对豆浆中大豆异黄酮含量及降解动力学的影响

大豆中苷元型异黄酮可直接被人体消化吸收,而其他异黄酮必须要经过水解去除糖基后才能被吸收利用。本研究通过模拟工业生产中常用的巴氏杀菌(95℃)、高温短时杀菌(121℃)和超高温瞬时杀菌(143℃),阐述了豆浆加热过程中异黄酮单体之间的转化,并对主要异黄酮的热降解进行了动力学分析,以期为生产高比例苷元型异黄酮的豆浆提供理论依据。生豆浆中丙二酰型异黄酮含量最高,其次分别为糖苷型和苷元型。3种热处理均导致丙二酰型异黄酮含量降低,符合一级降解动力学,且温度越高,降解速率常数越大。95℃处理主要导致丙二酰型向糖苷型转化,而143℃时异黄酮主要发生降解而非转化。121℃处理后,豆浆中苷元型异黄酮含量显著增加,比生豆浆提高50%,显著提高了豆浆品质。相对其他两个热处理温度,高温短时杀菌能减少异黄酮分解提高苷元型含量,更适合于豆浆工业化生产。     

β-葡萄糖苷酶对豆奶及豆奶粉中大豆异黄酮糖苷化合物的转化作用研究

对利用β-葡萄糖苷酶将豆奶及豆奶粉中生物有效性较低的异黄酮糖苷化合物转化为高活性的异黄酮糖苷配基化合物进行了试验研究。研究了不同浓度β-葡萄糖苷酶对豆奶及豆奶粉中大豆苷、乙酰大豆苷和丙二酰大豆苷的降解转化作用。结果表明,在β-葡萄糖苷酶浓度1.5U/mL、pH5.5、45℃保温1h的条件下,豆奶及豆奶粉中大豆苷、乙酰大豆苷和丙二酰大豆苷的总量分别降低了89.1%和89.5%,大豆黄素的含量分别增加了57.2和78.7倍;黄豆苷、乙酰黄豆苷和丙二酰黄豆苷的总量分别降低了93.2%和87.7%,黄豆黄素的含量分别增加了4.2和11.7倍;染料木苷、乙酰染料木苷和丙二酰染料木苷的总量分别降低了93.8%和82.4%,染料木黄酮的含量分别增加了5.2和23.0倍。试验结论:利用β-葡萄糖苷酶能够将豆奶及豆奶粉中生物有效性较低的异黄酮糖苷化合物高效转化为高活性的异黄酮糖苷配基化合物。     

高效液相色谱-质谱法在大豆异黄酮测定中的应用

应用高效液相色谱 -质谱法检测东北地区生产的 6个品种的大豆及其胚芽中异黄酮的含量 ,检测到 6种类型的异黄酮。 6个品种的大豆全豆异黄酮含量为 0 .15 1%～ 0 .388% ,胚芽异黄酮含量为 1.4 5 6 %～ 3.0 3% ,所测大豆因品种差异而致异黄酮含量相差 1倍以上。在天然状态下 ,异黄酮主要以丙二酰形式存在 ,所测结果在 80 %以上。在全大豆中 ,异黄酮以染料木素糖苷 (genistin)及其衍生物为主 ,占异黄酮总含量的 5 6 %～ 6 8% ,在胚芽中 ,异黄酮以大豆黄素糖苷 (daidzin)和黄豆黄素糖苷 (glycitin)及其衍生物为主 ,分别占异黄酮总含量的 4 5 %～ 5 1%和2 1%～ 2 8%。     

纤维素酶水解大豆异黄酮糖苷混合物的抗氧化活性

大豆异黄酮主要以糖苷类型的分子形式存在于大豆中,但是其具有生物活性的部分主要是苷元.为了建立一种体外生物转化大豆异黄酮糖苷为大豆异黄酮苷元的新方法,采用纤维素酶水解70%乙醇提取脱脂大豆粕得到的异黄酮粗提物,对比了水解前后两样品的异黄酮组成差异,并测定了其清除DPPH自由基的能力.结果表明:纤维素酶能完全水解大豆苷和染料木苷为大豆素和染料木素;而不能水解丙二酰基染料木苷和丙二酰基大豆苷.纤维素酶处理以后的大豆异黄酮糖苷混合物达到DPPH自由基50%清除率所需要的异黄酮浓度是未处理的大豆异黄酮糖苷混合物的1/2.56.     

纤维素酶对黑大豆和葛根异黄酮糖苷不同组分的水解活性

异黄酮主要以糖苷的分子形式存在于黑大豆和葛根中,但是其具有生物活性的部分主要是苷元.为了建立一种体外生物转化异黄酮糖苷为异黄酮苷元的新方法,采用70%乙醇提取黑大豆和葛根异黄酮,用高效液相色谱分析了纤维素酶水解前后两粗提物的异黄酮组成.结果表明:纤维素酶对于不同种类的异黄酮糖苷具有不同的水解专一性、基团专一性和键专一性,能完全水解大豆苷和染料木苷为大豆素和染料木素,而不能水解丙二酰基染料木苷、丙二酰基大豆苷和葛根素.     

豆制品中大豆异黄酮转化与富集的研究进展

大豆异黄酮属于黄酮类化合物,主要分为结合型大豆异黄酮糖苷和游离型大豆异黄酮苷元。游离型大豆异黄酮苷元具有比结合型大豆异黄酮糖苷更高的生理活性,如预防骨质疏松和女性更年期综合症,抗氧化和抗癌抑癌等。大豆异黄酮在食品保健方面应用前景广阔,国内外研究者对大豆异黄酮研究越发深入。该文主要综述豆制品中大豆异黄酮的转化和富集方法,旨在为生产富含大豆异黄酮苷元的功能性豆制品研究提供参考。     

HPLC-ESI-MSn法鉴定大豆中12种大豆异黄酮的结构

为了鉴定大豆异黄酮的结构,采用高效液相色谱-电喷雾离子源-离子阱多级质谱联用仪(HPLC-ESI-MSn)法分离鉴定大豆粉乙醇提取物,通过多级质谱提供的准分子离子峰和多级碎片离子信息,分析得到了12种大豆异黄酮的相对分子质量、保留时间并推断了它们异黄酮糖苷的组成结构、异黄酮糖苷中糖的类型等,这12种大豆异黄酮分别是大豆苷元、大豆黄素、染料木素、大豆苷、大豆黄苷、染料木苷、乙酰基大豆苷、乙酰基大豆黄苷、乙酰基染料木苷、丙二酰基大豆苷、丙二酰基大豆黄苷、丙二酰基染料木苷。     

两步水解酶法制备大豆异黄酮苷元初探

利用二步水解法制备大豆异黄酮苷元。经弱碱水解丙二酰基大豆异黄酮为糖苷型大豆异黄酮,再经果胶酶进一步水解获得富含苷元的大豆异黄酮。采用单因素试验和正交试验,得到果胶酶制备大豆异黄酮苷元的较优工艺条件:果胶酶水解时间20 min,水解温度47.5℃,水解pH值4.2,酶-底物质量比为0.80%。苷元水解得率为87.37%。     

大孔树脂分离纯化大豆胚芽中异黄酮的研究

通过柱层析的方法使大豆胚芽中异黄酮的苷元和糖苷得到有效的分离。紫外检测结果显示,大豆胚芽提取液中异黄酮含量为5.35%;HPLC检测结果显示:以AB-8大孔树脂为固定相,乙醇水溶液进行递度洗脱,可使大豆异黄酮的苷元和糖苷得到很好的分离,苷元和糖苷的纯度可达90%以上。     

INFLUENCE OF HEAT TREATMENT AND GRAIN GERMINATION ON THE ISOFLAVONE PROFILE OF SOY MILK

Soy foods have attracted much attention for their possible effects on human health because of their phytochemical content, mainly isoflavones. Twelve forms of isoflavones have been identified in soybeans and soy products. Technological processes like heat treatment or fermentation can change the isoflavone profile of soy products. In this study, the effects of heat treatment and grain germination on isoflavone profile of soy milk prepared from BRS 213 soybean variety were evaluated. Isoflavone forms were separated and quantified by reversed‐phase high‐performance liquid chromatography. Heat treatment by autoclaving for 5 min did not affect the total isoflavone content, but led to a 90% decrease in malonyl forms, whereas β‐glycosides increased by 70%. Autoclaving for 15 min led to a 20% loss of total isoflavones. Germination for 3 days did not change the total isoflavone content, but changed the distribution profile (15% increase of malonyl forms and 30% decrease of β‐glycosides). Germination for 7 days increased the bioavailability of aglycone isoflavones in soy milk by seven times.     

Urinary isoflavone excretion in Korean adults: comparisons of fermented soybean paste and unfermented soy flour

BACKGROUND: This study compared the 24 h urinary excretion of isoflavone algycones after the consumption of fermented soybean paste or unfermented soy flour in a population of healthy Koreans (four males and five females). An equivalent amount (20 mg) of total isoflavone was consumed as either 52 g of soybean paste or 12.2 g of soy flour in a randomised, crossover trial consisting of two single‐time‐point feedings and having 3 day run‐in and washout periods between feedings. RESULTS: Analysis of starting materials indicated that daidzein (1.4%) and genistein (1.4%) constituted a smaller proportion of the total isoflavones in soy flour as compared with soybean paste (55.3% daidzein and 45.7% genistein). Free and glycosidic forms of isoflavones differed significantly between the two soy products. Levels of β‐glycosides as well as total glycosides (β‐glycosides, malonyl and acetyl forms) were two‐fold higher in soy flour as compared with soybean paste. Malonyl forms predominated in soy flour. CONCLUSIONS: The consumption of soybean paste resulted in significantly higher urinary excretion of both daidzein and genistein as compared with soy flour (P < 0.05 and P < 0.01 respectively). Copyright © 2007 Society of Chemical Industry     

大豆异黄酮提取及其生物转化的研究进展

大豆异黄酮是大豆生长过程中形成的一种次级代谢产物,主要以糖苷和游离苷元的形式分布于大豆的子叶和胚轴中。研究表明,游离型大豆异黄酮具有许多重要的生理功能,诸如抗氧化、抗癌抑癌、保护心血管、预防骨质疏松及女性更年期综合症等。随着科学技术的进步,大豆异黄酮的应用日趋广泛。对国内外大豆中异黄酮的提取方法及其优缺点,以及由糖苷型大豆异黄酮转化为游离苷元的方法进行综述,以期为大豆异黄酮的应用研究提供帮助。     

弱碱水解丙二酰基型大豆异黄酮的研究

本实验采用碱法将丙二酰基大豆异黄酮水解为葡萄糖苷型大豆异黄酮。通过正交实验得到最佳碱水解条件为:PH=11.0,水解温度65℃,水解时间1h。水解前样品中大豆异黄酮的含量分别是:D:16.12%,G:14.49%,MD:33.62%,MG:35.77%,水解后样品中大豆异黄酮的含量分别是:D:46.86%,G:47.34%,MG:5.80%,MD:nd。     

大豆异黄酮及其苷元的研究进展

大豆异黄酮是一种天然的雌激素,是大豆生长过程中的次级代谢产物,其主要位于大豆种子的子叶和胚轴中。其中97%左右以糖苷形式存在,其余以苷元形式存在,大豆异黄酮苷元是其发挥主要功能活性的形式。目前大豆异黄酮的常规提取方法包括有机溶剂萃取法、超声波辅助提取法、微波辅助提取法、超临界流体萃取法、亚临界水法等。研究表明,大豆异黄酮及其苷元具有一定的生理功效,包括预防心血管疾病,预防骨质疏松,抗肿瘤和神经保护等。本文在介绍大豆异黄酮及其苷元的组成、化学结构特性的基础上,详细综述了大豆异黄酮及其苷元的研究概况、提取工艺和主要功能活性,并展望了该领域今后的发展趋势和有待加强的研究方向,旨在为大豆异黄酮及其苷元产业化开发和深入研究其临床应用价值提供参考依据。     

Profiling and quantification of isoflavones in soymilk from soy protein isolate using extracted ion chromatography and positive ion fragmentation techniques

Dietary supplements on soy based foods and beverages are increasingly gaining prominence all over the world. In this study, liquid chromatography coupled with positive electrospray ionisation tandem mass spectrometry (LC-ESI-MS) and diode array detection was used for the quantitation and characterisation of isoflavones in fermented and unfermented soymilk made from soy protein isolate SUPRO 590. Bifidobacterium animalis ssp. lactis Bb12 was used for the fermentation of soymilk. The isoflavones were found to produce characteristic radical ions as well as molecules of H₂O, CO₂, a sugar unit, and an alcohol through collision-induced fragmentation. Product ion fragments revealed unique fragmentation pathways for each isoflavone compound. Characteristic fragmentation of different isoflavones were unequivocally identified and differentiated. The occurrence of aldehydes such as pentanal, ethanal and methanal was shown to be specifically linked with isoflavone aglycones, daidzein, genistein and glycitein, respectively. Main glycosides such as genistin, daidzin and glycitin as well as the acetyl-, and malonyl forms also showed respective aglycone ions in their spectra fragmentation. Thus positive ion fragmentation was important in the absolute confirmation of isoflavones and to reveal the occurrence of other related compounds such as aldehydes in soymilk.     

丹贝异黄酮的提取分离与结构鉴定

从丹贝中分离纯化了 3种异黄酮 ,它们分别是染料木素、大豆黄素、黄豆黄素 ,而未分离到 6 ,7,4’ -三羟基异黄酮。丹贝中异黄酮的组成主要是各种苷元 ,证明丹贝生物活性的提高是由于异黄酮由糖苷水解成苷元所致。同时还发现 ,使用甲醇作溶剂在分离纯化过程中可能使染料木素转变成黄豆黄素     

大豆胚轴中异黄酮的提取及其抗血小板聚集作用的研究

从大豆胚轴提取总糖苷后，采用C18反相柱层析法分离大豆异黄酮糖苷，再将其水解制备成异黄酮苷元，并研究大豆异黄酮对人血小板聚集性的影响。结果：在体外人血小板聚集实验中，大豆异黄酮苷元均抑制ADP、胶原蛋白和肾上腺素诱导的血小板聚集。提示：大豆异黄酮可能有助于防止血栓形成。     

Skim milk powder supplementation affects lactose utilization, microbial survival and biotransformation of isoflavone glycosides to isoflavone aglycones in soymilk by Lactobacillus

Four probiotic bacteria, Lactobacillus acidophilus 4461, L. acidophilus 4962, Lactobacillus casei 290 and L. casei 2607, were used for fermentation of soymilk (SM) prepared from soy protein isolate (SPI) supplemented with skim milk powder (SMP) (SSM). Soymilk and reconstituted skim milk (RSM) were used as controls. Lactose utilization in SSM by these probiotic organisms ranged from 14.97 to 18.15mg/ml, compared to 14.12-16.06mg/ml for RSM. The pH in SSM dropped to 4.07-4.29 compared to 6.15-6.36 for SM and 4.10-4.96 for RSM. The microbial viable counts were also significantly enhanced by up to 0.98logCFU/ml by the supplementation of SMP to SM. The biotransformation level of isoflavone glycosides (IG) to isoflavone aglycones (IA) in SSM ranged from 81.4% to 85.1%, which was 13.9-19.0% higher than that for SM, after 24h of incubation. Most of IG in SSM was completely converted to IA, except malonyl glycitin and malonyl genistin. At the end of the incubation, IA comprised up to 76.8% of total isoflavones in SSM.     

Relative antioxidant activity of soybean isoflavones and their glycosides

The present study compared the antioxidant potency of genistein and daidzein with their corresponding glycosides isolated from soybean seeds. The antioxidant activity was assessed using three methods, namely human low-density lipoprotein (LDL) oxidation, the ferric reducing-antioxidant power (FRAP) and the anti-DPPH free radical assays. It was found that soybean was rich in genistein and daidzein but they were present mainly in form of glycosides. Both the FRAP and the anti-DPPH assays demonstrated that these glycosides, as well as genistin, daidzein, glycitin, malonyl glycitin and malonyl genistein possessed similar antioxidant activities to their corresponding aglycones, genistein and daidzein. In contrast, the antioxidant potency of these glycosides was much weaker than their corresponding aglycones, genistein and daidzein, in the LDL oxidation assay. The present results demonstrate that genistein and daidzein were less effective, as antioxiants in the three assays, than two well-defined antioxidants, green tea epicatechin and -tocopherol. It is concluded that soybean isoflavones and their glycosides possess antioxidant activity but they are ineffective antioxidants compared with tea epicatechins and -tocopherol.