大豆异黄酮糖苷酶的发酵和纯化

大豆异黄酮糖苷酶可水解大豆异黄酮的糖基使其生成苷元,从而提高大豆异黄酮的生物活性。实验中筛选得到了大豆异黄酮糖苷酶产酶菌株 Absidia sp．R,确定了该菌株发酵产酶培养基。采用硫酸铵沉淀和离子交换法对该酶进行了纯化,并初步确定了其分子质量。     

酱油渣异黄酮抗氧化功效成分纯化研究

以酱油渣为原料,采用乙醇提取法提取酱油渣中大豆异黄酮,对提取条件进行了优化。比较了醇沉法、等电点沉淀法、浓缩离心法、正丁醇法、二氯甲烷法、乙酸乙酯萃取法等6种方法对异黄酮粗提物的纯化效果。通过高效液相鉴定了纯化产物的异黄酮单体组成,并采用邻苯三酚氧化法和DPPH法评价了异黄酮纯化物的体外抗氧化活性。结果表明：优化条件下提取的异黄酮粗提物中异黄酮质量分数为1.21%、提取率为（85.36±0.09）%。6种纯化方法中,浓缩离心法所得异黄酮产物中异黄酮纯度为7.75%,去除蛋白质效果最佳;二氯甲烷萃取法所得异黄酮产物中异黄酮纯度为27.74%,去除总糖和灰分效果最佳;两者联用后所得纯化产物的异黄酮纯度为44.88%,其主要由染料木素、大豆黄素和大豆素组成,质量分数分别为67.37%、9.33%、23.30%。在质量浓度为1 mg/mL时,异黄酮纯化物对超氧阴离子、DPPH自由基的清除率分别为67.65%、89.18%,显著高于异黄酮粗提物（P＜0.05）,其IC50分别为0.34、0.26 mg/mL,说明异黄酮纯化物具有一定的抗氧化活性,有望作为一种潜在的天然抗氧化剂应用于功能性食品中。     

大豆异黄酮糖苷水解研究进展

该文在介绍大豆异黄酮的组成、化学结构、特性及生理功能基础上,详细介绍水解法制备大豆异黄酮苷元原理、工艺流程、大豆异黄酮苷元分离纯化及检测方法。     

几种水解法制备高纯度大豆异黄酮甙元工艺比较研究

以低纯度商品大豆异黄酮为原料,利用酸水解法、超声波辅助酸水解法及酶水解法制备高纯度大豆异黄酮甙元产品。通过实验,比较这三种水解制备方法水解率、产品回收率和产品纯度,并对制备得到产品进行成分分析,选择出较佳制备高纯度大豆异黄酮甙元方法。实验结果表明,采用β―葡萄糖苷酶水解分离纯化工艺制备大豆异黄酮甙元产品,操作简单,安全环保,其产品得率、异黄酮回收率和产品纯度分别为15.1%、77.1%和92.7%,分离纯化效果较理想。     

大豆异黄酮、大豆皂甙纯化工艺研究

通过比较纯化方法确定以吸附法进行分离纯化,通过对五种大孔吸附树脂HPD-100、HPD-300、HPD-600、AB-8和H103的吸附性能研究,确定选择H103从豆粕乙醇提取物的水分散液中吸附异黄酮和皂甙。再在柱后串联对皂甙有良好吸附性的HPD-600吸附剂回收流失皂甙。经树脂纯化后大豆异黄酮和大豆皂甙的纯度分别为37.3％,53.4％,产品中总有效成分含量为90.7％。     

大豆异黄酮的分离纯化

本文主要介绍了大豆异黄酮化学组成、性质及分离纯化技术。天然大豆异黄酮多以苷的形式存在,提取方法一股采用乙醇提取法和超声波辅助提取法。由于提取液中含有各种杂质,通常采用沉淀法、萃取法、膜分离、吸附法等分离技术进行纯化。     

大孔吸附树脂对大豆异黄酮的吸附与洗脱性能

研究了几种大孔吸附树脂对母液中大豆异黄酮的吸附与洗脱性能 ,从中筛选出了D4 0 2 0树脂 .对母液中的大豆异黄酮进行了纯化 ,纯化后产品的纯度可达 4 0 %以上 ,能够满足市场的要求     

沉淀法提纯大豆异黄酮影响因素的确定

大豆异黄酮提取过程中会有许多杂质,如皂甙、低聚糖、蛋白质等,其中蛋白质对大豆异黄酮的纯化影响较大,易与异黄酮发生缔合作用而影响异黄酮的精制。用絮凝沉淀法去除异黄酮提取液中的蛋白质,可明显提高大豆异黄酮提取液的纯度。本实验用101絮凝剂作正交实验,确定了最佳生产工艺参数,为生产高纯度异黄酮产品提供参考。     

大豆β-葡萄糖苷酶水解大豆异黄酮糖苷的研究

本文研究了大豆β-葡萄糖苷酶的提取、酶学性质以及其水解大豆异黄酮糖苷能力.该酶反应的最佳温度为45℃,最佳pH为5.00;在pH值为5.00～7.00时和低于40℃较稳定;70℃时酶活性基本全部丧失.初步纯化的大豆β-葡萄糖苷酶具有较高的水解大豆异黄酮糖苷能力.     

离心法纯化大豆异黄酮的研究

采用正交试验对离心法纯化大豆异黄酮的条件进行了优化。结果表明,当溶液中大豆异黄酮浓度为20mg/mL,溶液温度为40℃,离心速度为2×103r/min,离心30min,大豆异黄酮的含量可由原来的40.9%提高到71.2%,收率为32.3%。     

大豆异黄酮的提取及精制

简要介绍了大豆异黄酮的组成及其物理和化学性质,并着重介绍了几种适用于工业化生产的提取、精制大豆异黄酮的生产工艺。大豆异黄酮的提取常用乙醇水和弱碱性水溶液提取。其精制则用吸附树脂法、超滤膜与吸附树脂结合的方法以及吸附与溶剂萃取相结合等多种方法。     

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。     

Physicochemical and in vitro digestion properties of soy isoflavones loaded whey protein nanoparticles using a pH-driven method

Soy isoflavones are widely used as a dietary supplement. However, the bioavailability of soy isoflavones is low due to the poor water solubility. Whey protein is an excellent biopolymer to encapsulate functional ingredients. In this study, soy isoflavones loaded whey protein nanoparticles were prepared using a pH-driven method. The physicochemical properties and in vitro digestion properties of the nanoparticles were investigated. The results showed that the physicochemical properties of nanoparticles were regulated by the mass ratios of soy isoflavones to whey proteins. Hydrogen bonding and hydrophobic interactions were confirmed in generating soy isoflavones loaded nanoparticles, which modified the thermal stability and secondary structure of whey proteins. The nanoparticles could pass through simulated gastric digestion to deliver soy isoflavones into the intestinal tract, responsible for the increased digestion stability and bioaccessibility of soy isoflavones. Moreover, the controlled release of soy isoflavones from nanoparticles can be achieved with a mechanism of non-Fickian diffusion. This study may provide useful information about the utilization of soy isoflavones loaded whey protein nanoparticles to develop functional foods.     

大豆异黄酮与肠道微生物相互作用研究进展

膳食摄入大豆异黄酮与人体健康有密切的关系。大豆异黄酮糖苷组分与肠道菌群相互作用可产生生物活性和生物可利用度显著提高的新型微生物转化物,促进大豆异黄酮生理活性充分发挥。同时,大豆异黄酮通过调控肠道菌群结构影响结肠中的微生物酶活性,改变结肠菌群代谢能力。本文将对大豆异黄酮与肠道微生物的相互作用进行综述,重点阐述肠道微生物对大豆异黄酮的生物转化作用、大豆异黄酮对肠道微生物及其酶活性的调控作用以及大豆异黄酮及其肠道转化产物对健康的作用。以期为膳食组分和肠道菌群相互作用促进人体健康研究领域提供理论参考。     

大豆异黄酮对青年雌性大鼠卵巢、子宫组织中Bcl-2 mRNA 和Bax mRNA 表达的影响

目的：通过动物实验研究,观察Bcl-2 mRNA 和Bax mRNA 在青年雌性大鼠卵巢和子宫组织中的表达情况,从细胞凋亡角度研究大豆异黄酮对青年雌性大鼠的抗衰老作用。方法：选用2 月龄青年雌性大鼠50 只,按体质量分成5 组,每组10 只,分别为对照组(基础饲料)、低剂量组(大豆异黄酮100mg/(kg bw·d))、中剂量组(大豆异黄酮200mg/(kg bw·d))、高剂量组(大豆异黄酮300mg/(kg bw·d))、雌激素组(己烯雌酚0.5mg/kg 饲料),实验周期7 周。采用原位杂交法检测各组大鼠卵巢和子宫组织中Bcl-2 mRNA 和Bax mRNA 的表达水平。结果：大豆异黄酮能够增强大鼠卵巢和子宫组织中Bcl-2 mRNA 的表达水平;而各剂量组大鼠卵巢和子宫组织中Bax mRNA水平呈下降趋势。结论：大豆异黄酮可以增强抗凋亡基因Bcl-2 mRNA,拮抗促凋亡基因Bax mRNA 的水平,推测这是大豆异黄酮对青年雌性大鼠发挥抗衰老作用的途径之一。     

Efficacy of isoflavones in relieving vasomotor menopausal symptoms – A systematic review

This review assessed the efficacy of isoflavone supplements to reduce vasomotor symptoms in menopausal women by reviewing all published randomized controlled trials. Systematic literature searches were carried out in 70 databases. Randomized and placebo controlled studies were included if they investigated the treatment of isoflavone supplements derived from soy or red clover on vasomotor symptoms in peri‐ or postmenopausal women for at least 12 wks. Data were analyzed concerning outcome and methodological quality of the study. Twenty‐three trials met the inclusion criteria, thereof 17 investigated soy isoflavones and 6 red clover isoflavones. Without exception, selected trials examining the effect of red clover isoflavones were already assessed in several meta‐analyses and were therefore excluded from this evaluation. As the soy isoflavone studies were very heterogeneous concerning interventions and outcome measures, meta‐analysis could not be performed and trials were systematically assessed in a structured approach. Included soy isoflavone studies had numerous quality deficiencies and did not consistently show a reduction of flushes after treatment with soy isoflavones. Therefore, there is no conclusive evidence, but only some indication of a benefit of soy isoflavones on hot flush frequency or severity.     

Apoptotic effects of cooked and in vitro digested soy on human prostate cancer cells

Previous laboratory and animal studies reported that soy isoflavones were major bioactive compounds in soy to exert chemoprotection of prostate cancer. However, these studies cannot reflect the realistic effects that soy may induce through diets, and little is known about the bioavailability of isoflavones from whole soy food and their bioactivities after cooking and digestion. In this study, cooking and in vitro digestion were used to prepare soy extracts and the effects of cooking and digestion on the isoflavone contents and bioactivities of the whole soy extracts were examined. The cooking procedure generally increased the amount of daidzin, genistin and daidzein, but decreased that of genistein. Digestion process significantly lowered contents of daidzin and genistin in 60min cooked sample, while increased the contents of daidzin and daidzein and decreased the content of genistein in the uncooked sample. Antioxidant activities of soy extracts increased after cooking and in vitro digestion, while no consistent increase of the four soy isoflavones was determined. The apoptotic effects of soy extracts on both LNCaP and C4-2B cells were generally in a dose-dependent manner. Compared to purified single isoflavones, cooked and digested soy were more effective on induction of prostate cancer cell apoptosis, which indicated synergistic interactions between various bioactive compounds in the whole soy.     

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。     

Stability and Shelf Life of Bioactive Compounds during Food Processing and Storage: Soy Isoflavones

ABSTRACT: During the past several years, the nutrition community has recognized the importance of the nonnutritive components of plant foods. These nonnutritive components are commonly called phytochemicals. One of the most exciting developments in the phytochemicals field is the beneficial biological activity of isoflavones from soy. Benefits include the potential reduced cancer risk, cholesterol homeostasis, and other hormone replacement therapy treatments. Yet, very little attention has been given to the interactions of bioactive phytochemicals with other food ingredients. Various studies demonstrated the loss of soy isoflavones during storage and the effect of processing conditions on specific modifications of soy isoflavones. Beyond apparent 1st-order degradation kinetics, there is a change in the isoflavones profile according to processing and storage conditions. This change in chemical structure is very likely to affect the bioavailability and bioactivity of soy isoflavones. Understanding the reactions that affect soy isoflavones bioactivity will provide a basis for developing food with the beneficial quality of isoflavones. This article presents current information on the stability of soy isoflavones and highlights how these changes may affect their bioavailability and biological activity. Most importantly, the aim of this article is to point out the fact that much more data are required to fully understand the chemistry and the kinetics of isoflavones reaction in model systems and food.     

Evaluation of the composition and concentration of isoflavones in soy based supplements,health products and infant formulas

Isoflavones are weak estrogenic compounds found in soybeans and soy foods. The objective of the present study was to determine the content and composition of isoflavones in different soy isoflavone supplements, soy based health products and infant formulas. Commercially available samples of 13 different soy supplements and 11 soy based health products obtained from South East Asia were analyzed for their isoflavone concentrations by using high-performance liquid chromatography and their peak identities confirmed by LC–MS. The extent of daily intake of isoflavones from different products based on the directions for their consumption was further evaluated. The amount of isoflavones in dietary supplements, soy based health products and infant formulas ranged from 405 to 57,570, 46.32–1333.80 and 59.54–226.84 μg/g of the sample, respectively, expressed as aglycone equivalents.