淡豆豉、黄大豆及黑大豆体内外抗蛋白非酶糖化作用研究

为比较豆类及其发酵品抗蛋白非酶糖化作用, 以四氧嘧啶腹腔注射小鼠复制糖尿病模型,正常组和模型组灌胃自来水,黄大豆组、黑大豆组、淡豆豉组(均18.5g生药/kg·d)连续灌胃56d,取血清和主动脉弓测定糖化终末产物.体外试验将牛血清白蛋白(BSA)与D-葡萄糖体外孵育,与此同时分别加入不同浓度的淡豆豉、黄大豆和黑大豆提取物,糖化系统建立90d时,测定各反应体系荧光值.结果表明,各组豆类主动脉糖化终末产物明显降低(p<0.05,P<0.01);除黑大豆组外血清糖化终末产物明显降低(p<0.01).豆类体外能明显抑制非酶糖化反应的最低浓度在1～100mg/ml之间,且随浓度升高,抑制作用明显.在同等浓度下,淡豆豉的抑制作用强于两种大豆,而两种大豆之间无明显区别.本研究豆类具有抗蛋白非酶糖化作用,其中发酵品淡豆豉作用最强.     

酶法提高豆浆中大豆异黄酮苷元浓度的工艺研究

试验利用黑曲霉β-葡萄糖苷酶处对豆浆进行水解处理,将结合型大豆异黄酮糖苷转化为游离型苷元。选大豆为原料,以单因素实验为基础,考察加酶量、反应时间、反应温度三个因素对豆浆中大豆异黄酮糖苷水解的影响;根据Box-Behnken实验设计原理,选取不同加酶量、反应时间、反应温度3因素3水平进行中心组合实验,建立豆浆中大豆异黄酮苷元含量的多项式回归预测模型,确定了最佳工艺参数。结果表明,最佳水解工艺条件为:加酶量0.028 U/5 mL,反应时间1.64 h,反应温度53.82℃,在此条件下制得豆浆大豆异黄酮苷元含量明显提高。测得大豆苷元(De)、黄豆黄素(Gle)、染料木素(Ge)的浓度分别为39.434±1.410μg/m L、4.626±0.462μg/m L、45.851±2.098μg/m L。而大豆苷元(De、)黄豆黄素(Gle)、染料木素(Ge)浓度的响应面预测值分别为40.905μg/m L、4.263μg/m L、48.441μg/m L,测定值与模拟值接近。优化后的工艺条件合理、可行,能明显提高豆浆中大豆异黄酮苷元的含量。     

发酵大豆食品中染料木素含量的ELISA测定

染料木素是大豆发酵食品中的主要异黄酮成分。制备了牛血清白蛋白-染料木素免疫抗原和卵白蛋白-染料木素包被抗原,并对它们进行紫外和SDS-聚丙稀酰胺凝胶电泳鉴定。抗染料木素抗体的效价为1:1600。建立竞争ELISA测定发酵大豆制品中染料木素含量方法,染料木素测定浓度范围为6.25～150μg/L;回收率为87%～102%;亲和常数为1.62×108;与大豆甙元、芒柄花素的交叉反应率分别为9.8%、4.57%;与槲皮素、儿茶素、单宁和核黄素等结构类似物无交叉反应。同时将ELISA法与薄层层析法进行比较。     

浸泡过程对家用豆浆机所制豆浆异黄酮含量的影响

大豆浸泡过程会一定程度激活其内源酶,可能对家用豆浆机所制豆浆的异黄酮产生影响。该试验以不同浸泡条件下的大豆为原料制作豆浆,采用高效液相色谱分析豆浆中主要的异黄酮物质的含量。研究发现豆浆中异黄酮以染料木苷和大豆苷为主,干豆豆浆中染料木苷、大豆苷及对应的苷元含量分别为71.50,60.30,6.80,5.10 mg/L。浸泡豆豆浆的总异黄酮含量与之无显著差异,但苷元含量则显著提升。在60℃浸泡1.8 h的条件下,所制豆浆中染料木苷、大豆苷以及对应的苷元含量分别为75.17,62.84,10.66,7.58mg/L,两种苷元含量分别提升了56.8%和48.6%。同时,60℃浸泡豆较干豆所制豆浆的固形物和蛋白质含量均有显著提高。因此,可考虑采用60℃饱和浸泡来提升豆浆中活性异黄酮的含量。     

酶水解对大豆异黄酮粗提物中苷元含量的影响

采用β-葡萄糖苷酶水解的方法将大豆异黄酮糖苷转化为苷元,以染料木素和大豆苷元含量为指标,通过单因素试验对水解过程中的不同影响因素进行了考察。以染料木素含量为指标,运用正交试验优化了β-葡萄糖苷酶水解大豆异黄酮的工艺条件为反应温度40℃、水解时间1.5h、水解介质pH4.5、水解底物浓度10mg/mL,在此条件下,水解得到的大豆异黄酮苷元中染料木素的含量可达到22.91%。     

桑黄提取物对体外蛋白质非酶糖化的抑制作用

采用牛血清白蛋白-葡萄糖建立体外蛋白非酶糖化反应体系,考察温度、时间和葡萄糖浓度对糖化程度的影响。在37℃,牛血清白蛋白20 g/L,葡萄糖400 mmol/L,温育20天即可产生稳定可测的Amadori产物,温育40天可造成蛋白明显糖化,选定该体系考察桑黄提取物对体外蛋白质非酶糖化反应的抑制作用。结果显示,桑黄醇提物对Amadori产物和终产物AGEs的IC_(50)值分别为81×10~(-2) mg/m L和7.3×10~(-2)mg/m L,说明桑黄醇提物对蛋白质非酶糖化反应具有较强的抑制作用;桑黄水提物对Amadori产物抑制作用较弱,但能够有效抑制AGEs的生成,IC_(50)值为8.4×10~(-2) mg/m L,说明桑黄水提物也具有一定的抑制蛋白质非酶糖化作用。该研究结果表明桑黄醇提物和桑黄水提物都可以作为抗糖化物质进行开发应用。     

酶法水解大豆异黄酮

利用Absidiasp R菌株 ,通过液体发酵 ,得到了一种高活性的大豆异黄酮糖苷水解酶 ,该酶水解糖苷型大豆异黄酮的最适底物浓度为 7 5mg/mL ;最适反应时间为 1 5h ;该酶在温度为 2 0～5 0℃、pH为 4 0～ 7 0范围内相对稳定 ,最适酶解反应温度为 40℃ ,最适pH值为 5 0 ;金属离子对该酶活力的影响不显著 ,其中Co2 +、Zn2 +对该酶有激活作用 ,Ag+、Cu2 +对该酶有抑制作用 ,Fe3+浓度<5 0mmol/L时 ,对该酶有促进作用 ,当离子浓度 >5 0mmol/L时 ,则有抑制作用。利用实验获得的最适酶解条件反应 ,可使染料木苷生成染料木素的转化率达到 1 0 0 %。     

北京地区不同大豆品种异黄酮含量比较研究

异黄酮是大豆生长过程中自然产生的化学物质,被认为可以治疗和预防一些人类依赖激素的疾病.为比较北京地区生态条件下大豆品种间异黄酮含量的差异性,对53个品种种子中3种异黄酮(大豆苷元、染料木素和黄豆黄素)进行测定和分析.结果表明,品种间异黄酮含量存在较大多样性,大豆苷元为39.21～2 363.65 μg/g,染料木素为77.35～1 149.50 μg/g,黄豆黄素为0.0～51.30μg/g,3种异黄酮总量为146.73～2 845.60 μg/g.来自山西和山东品种的异黄酮含量显著高于其他地区的品种.异黄酮总量分别与大豆苷元和染料木素呈极显著正相关,而大豆苷元和染料木素之间没有互作.因此,可以利用高含量大豆苷元或染料木素材料选育高异黄酮品种.     

"Amano"β-糖苷酶水解大豆异黄酮技术的研究

研究了"Amano"β-糖苷酶水解大豆异黄酮技术工艺.通过单因素试验对水解过程中的不同影响因素进行了考察.运用正交试验优化了"Amano"β-糖苷酶水解大豆异黄酮的反应条件.该酶水解黄豆苷的最佳条件为:水解时间140min,加酶液浓度33μg/ml,pH4.5,温度50℃;水解染料木苷的最佳条件为:水解时间140min,加酶液浓度33μg/ml,pH4.5,温度60℃.验证实验证实用最佳反应条件水解大豆异黄酮可使黄豆苷的水解率达到 98.2%,染料木苷的水解率达到94.2%.     

苦杏仁β-葡萄糖苷酶水解豆浆中大豆异黄酮的工艺研究

大豆异黄酮的生理活性主要靠异黄酮苷元来发挥,该试验研究在豆浆中添加苦杏仁β-葡萄糖苷酶对大豆异黄酮苷元的影响。采取高效液相色谱检测的方法,通过响应面优化试验,得到最佳组合为:加酶量为1.4 U/5mL,酶解时间40 min,酶解温度46.0℃。测得染料木素(Ge)、黄豆黄素(Gle)、大豆苷元(De)的含量分别为(38.643±2.03)、(5.119±0.275)、(36.954±1.67)μg/mL。     

Functional attributes of soybean seeds and products,with reference to isoflavone content and antioxidant activity

The concentrations of isoflavones, especially daidzein and genistein, were determined by high performance liquid chromatography in 4 soybean cultivars and 26 soybean products. The total isoflavone content of the soybean cultivars was in the range of 525–986 mg per kg, and for soy products it was 32.9–795 mg per kg. Amongst the soybean products, the isoflavone content decreased in the order: soy sprouts, soy seeds, soy flour, soy milk, soy meals and soy sauce. Significant differences in the concentration of genistein and daidzein were observed between the commercial soy products and also within the soybean cultivars. The antioxidant activity of soybean and soy products correlated well with total phenolic content (TPC) and total isoflavones (TI), whereas TPC showed higher correlation with TI.     

植物乳杆菌58发酵豆乳产大豆异黄酮苷元条件的优化

本研究通过测定植物乳杆菌58在不同碳源中的生长和产β-葡萄糖苷酶情况,筛选菌株的最适碳源,并确定接种至豆乳的最佳时间。在接种量、糖含量、发酵时间和发酵温度等单因素实验基础上,根据Box-Behnken中心组合原理进行响应面实验设计,以大豆异黄酮苷元含量为指标,进一步优化菌株58发酵豆乳产大豆异黄酮苷元条件。结果显示,植物乳杆菌58生长和产β-葡萄糖苷酶的最适碳源为乳糖,酶活达0.66 U/m L,显著高于果糖、蔗糖、葡萄糖和麦芽糖(p<0.05)。菌株在乳糖碳源中培养18 h产酶活力最佳,达0.75 U/mL,且生长情况良好。响应面优化实验得出发酵豆乳大豆异黄酮最佳转化条件为:接种量3.80%,糖含量5.80%,发酵温度38.10℃,发酵时间9.80 h。此条件下,大豆异黄酮苷元含量预测值达68.63 mg/L,与实验值68.16 mg/L相比差异不显著,表明构建二次模型的科学性和准确性,与优化前(59.64 mg/L)相比提高15.07%,有助于乳酸菌发酵豆乳中大豆异黄酮糖苷向高生物活性和利用度大豆异黄酮苷元的转化。     

青方腐乳发酵过程中大豆异黄酮的转化研究

本文比较了青方、红方、白方和低盐红腐乳中大豆异黄酮组成和含量差异,并对青方腐乳发酵过程中大豆异黄酮含量和构型变化规律进行研究。结果表明,四种类型腐乳中大豆异黄酮基本以苷元形式存在,青方腐乳大豆异黄酮含量明显低于其他类型腐乳,仅为红方腐乳的33.01%,从单一异黄酮来看,大豆苷元和染料木素在四种类型腐乳中的含量明显高于黄豆黄素;青方腐乳发酵过程中大豆异黄酮转化研究发现,白坯中大豆异黄酮以糖苷型为主,染料木苷含量高于大豆苷和黄豆黄苷,前酵过程中糖苷型大豆异黄酮转化为苷元型大豆异黄酮,盐腌过程中糖苷型大豆异黄酮含量有轻微降低,发酵过程中苷元型大豆异黄酮总量在后酵前30 d显著下降,其中大豆苷元可能部分转化为雌马酚,导致青方腐乳大豆异黄酮含量明显低于其他类型腐乳,对其转化物质需进一步鉴定。     

Isoflavone concentration of soybean meal from various origins and transfer of isoflavones into milk of dairy cows

The objective of this study was to determine the isoflavone concentration of defatted soybean meals from Argentina, Brazil and USA. Moreover, the transfer of isoflavones from soybean meal into the milk of dairy cows was investigated in a preliminary dose?Cresponse study. Six samples of soybean meal from each origin imported into the EU were taken at European harbours and subsequently analysed. The animal experiment was designed as a dose?Cresponse study with different amounts of soybean meal. For this purpose, eight lactating German Holstein cows were fed individually with a maize silage based diet containing 0, 10, 20 or 30% soybean meal for five periods over 21?days. At the end of each feeding period, the collected milk was analysed for isoflavones using HPLC?CDAD?CMS/MS methodology. The average total isoflavone concentrations in mg per kg dry matter in soybean meal were 1570 from Brazil, 1944 from the USA and 3075 from Argentina. Altogether, genistin was predominant with average proportions from 27% (USA) to 39% (Brazil). In milk, genistein was the most prominent phytoestrogen measured at concentrations from 58.9 to 89.8???g/kg. Furthermore, traces of equol, enterolactone, formononetin and daidzein were detected, particularly, following soybean meal supplementation at high dosage. In conclusion, these results indicate an isoflavone transfer from feed into bovine milk.     

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     

雌马酚及大豆活性成分对人前列腺癌细胞DU145的生长影响

目的:观察大豆异黄酮代谢产物雌马酚对人前列腺癌细胞DU145的生长影响,并在生理浓度下比较其与大豆异黄酮主要成分金雀异黄素、大豆素的体外抗增殖活性。方法:采用MTT法检测不同浓度的雌马酚、金雀异黄素及大豆素对DU145细胞增殖的影响,并以流式细胞术分析细胞周期分布情况。结果:雌马酚在1×10-6～1×10-5mol/L表现为抑制作用,金雀异黄素在1×10-7～1×10-6mol/L时表现为促增殖效应,达到5×10-5mol/L时出现抑制作用,大豆素在生理浓度下则主要表现为促增殖效应;雌马酚在1×10-6mol/L时使细胞在G0/G1期阻滞,在5×10-6～1×10-5mol/L时使S期及G2/M期细胞增多,金雀异黄素在5×10-6mol/L出现G2/M期阻滞,大豆素使S期及G2/M期细胞增多。结论:雌马酚在体外具有一定的抗前列腺癌活性;在生理浓度下,其抗癌活性可能强于金雀异黄素及大豆素。     

不同大豆制品中大豆异黄酮含量的比较研究

大豆异黄酮是一类具有重要生物活性的化合物,在大豆及其制品中含量丰富。本实验采用乙醇热回流提取法研究大豆及其制品中异黄酮含量。结果表明:样品加标回收率大于99%,说明该方法适用于大豆样品异黄酮含量的测定;大豆及其制品中异黄酮含量的大小顺序依次为:大豆>豆浆>豆腐脑>卤水豆腐>腐竹>白豆干>豆腐皮>油豆腐>脆豆皮,表明加工工艺会影响大豆异黄酮的含量。     

大豆酸奶对秀丽隐杆线虫体内抗氧化和寿命的影响

该研究旨在利用野生型秀丽隐杆线虫N2对一款富含大豆异黄酮苷元的大豆酸奶进行生物活性评价。采用高效液相色谱法对该大豆酸奶中大豆苷元、黄豆黄素和染料木素的含量进行分析表明,结果表明其苷元含量比未发酵豆乳增加了26.4倍。采用体外抗氧化实验和野生型秀丽隐杆线虫N2对大豆酸奶的抗氧化活性进行评价,发现发酵后的混合豆乳对DPPH自由基、超氧自由基、ABTS+自由基的清除率分别为98.03%、73.77%、83.37%,比发酵前显著提高（P<0.05）。大豆酸奶样液可将秀丽隐杆线虫的平均寿命和最大寿命分别延长21.57%和22.58%;饲喂大豆酸奶样液后,线虫体内超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性显著增强,体内活性氧（ROS）水平显著下降（P<0.05）,线虫抗应激能力显著增加（P<0.05）。说明通过乳酸菌发酵制备高苷元含量的大豆酸奶,可有效提高产品抗氧化活性,并能延长秀丽隐杆线虫寿命。     

常见食用豆类中黄酮类化合物含量的测定

以芦丁为标样应用氯化铝显色法、硝酸铝显色法分别测定15种常见食用豆类中的黄酮类化合物总含量,以染料木素做为标样应用直接比色法测定其中食用豆类样品中异黄酮的总含量,利用高压液相色谱法测定常见食用豆类中的4种大豆异黄酮单体成分的含量.结果表明:使用氯化铝显色法进行测定,赤豆、绿豆等7种食用豆类显示含有黄酮类化合物,并且含量最多的赤豆为0.501 mg/g.硝酸铝显色法测定豆类样品黄酮类总合量为0.297～8.844mg/g.直接比色法测定食用豆类中异黄酮总含量为1m994～8.840mg/g.高压液相色谱法测定4种大豆异黄酮单体成分的总含量为0.031-3.345mg/g.     

Combination of low dose of genistein and daidzein has synergistic preventive effects on isogenic human prostate cancer cells when compared with individual soy isoflavone

The reduced incidence of prostate cancer (PCa) in Asia countries has been attributed to high soy diets, and major soy isoflavones, in particular daidzein and genistein, are thought to be the source of the beneficial and anti-cancer effects of soy foods. However, attention has been drawn to the safety of using high levels of soy isoflavones in humans, which is especially the concern for consumers taking regular soy isoflavone dietary supplements. The main objective of this study is thus to identify a soy isoflavone combination with lower levels of daidzein and genistein to be a more efficacious and safer chemo-preventive agent for PCa. The anticancer effects of daidzein and genistein, and their combinations on early-stage androgen-dependent PCa cells (LNCaP) and bone metastatic LNCaP-derivative PCa cells (C4-2B) were compared. Cells were treated with varying concentrations of daidzein, genistein (25–200 μM) or their combinations (25 or 50 μM) and cell proliferation, apoptosis, cell cycles and cellular uptakes of the isoflavones were measured after 48 h. Daidzein and genistein showed a synergistic effect on inhibiting cell proliferation and inducing apoptosis of both PCa cells. Twenty-five μM daidzein/50 μM genistein and 50 μM daidzein/50 μM genistein significantly increased the apoptotic effects on C4-2B cells although they did not show any effect when used individually. Except 50 μM daidzein/50 μM genistein, all other combinations had no impacts on cell cycles. For treatment with soy isoflavone combination, genistein was always better taken up than daidzein by both LNCaP and C4-2B cells.