丹贝异黄酮生物活性增强的机理研究

以少孢根霉RT-3孢子接种在含高浓度的大豆异黄酮提取物制成的发酵基质中，发酵36h后大豆异黄酮被部分水解成相应的苷元．用从丹贝中分离的β-葡萄糖苷酶与标准品染料木素糖苷和大豆苷元的糖苷作用10min，染料木素糖苷和大豆苷元的糖苷被水解成相应的苷元．结果表明：丹贝异黄酮生物活性增强是发酵剂RT-3孢子分泌的β-葡萄糖苷酶将异黄酮由糖苷水解成苷元，而苷元比糖苷有更强的活性．     

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。     

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%。     

保健食品中大豆异黄酮含量的高效液相色谱法测定

采用高效液相色谱法,对市场上销售的5种国产和进口大豆异黄酮保健食品中12种大豆异黄酮的含量进行测定.对3种苷元大豆素、黄豆素和染料木素,3种糖苷大豆苷、黄豆苷、染料木苷采用各自的标准品绘制标准曲线用内标法进行定量,对乙酰化或丙二酰化糖苷用对应糖苷的内标响应因子和转换因子来计算含量.结果表明,大豆异黄酮保健食品的质量参差不齐,存在着含量标示不准确的问题,甚至部分完全不含有大豆异黄酮,亟待加强对大豆异黄酮保健食品的市场监管.     

不同大豆种质种皮黄酮类色素的差异分析

为探究大豆种皮中黄酮类色素的含量和分布规律,选取167份大豆种质资源为实验材料,利用高效液相色谱(HPLC)法对大豆种皮黄酮类色素含量进行测定。结果表明：大豆种皮花色苷组分中矢车菊素-3-O-葡萄糖苷含量最多,异黄酮组分中大豆苷含量最高。花色苷组分在野生和半野生大豆种皮中高于栽培大豆。异黄酮组分中染料木苷在野生大豆中最高,黄豆黄苷在半野生大豆中最高,其他组分在栽培大豆中最高。栽培大豆黑色种皮花色苷组分、染料木苷和大豆苷元含量最高,青色种皮大豆苷和黄豆黄苷含量最高,双色种皮黄豆黄素含量最高。相关分析表明3类结合型糖苷内部、3类游离型苷元内部、3种花色苷组分内部两两相关极显著。大豆苷与游离型苷元、矢车菊素-3-O-葡萄糖苷相关显著。聚类分析将大豆材料划分为三大类群,第一类群除黄豆黄苷和飞燕草素-3-O-葡萄糖苷外,其他色素组分含量均最高,为黄酮类色素的研究和利用提供参考。     

热处理与大豆异黄酮苷元的转化分析

目的研究不同加热处理后大豆异黄酮苷元的含量和比例变化情况。方法大豆样品经烘箱50、100和150℃烘干,微波加热5min和炒熟等热处理后,由80%乙醇溶液超声提取,经高效液相色谱SB-C18柱(4.6mm×250mm,5μm)分离,0.2%冰乙酸+甲醇溶液梯度洗脱,紫外检测器260nm检测苷元和β-葡萄糖苷型大豆异黄酮含量。结果黄豆中检测出黄豆苷元、染料木素2种苷元和黄豆苷、黄豆黄苷2种β-葡萄糖苷。随烘箱加热温度升高,黄豆苷元含量增加1～5倍;染料木素增加3～15倍。炒豆中苷元和β-葡萄糖苷增加量最多。微波加热与50℃烘箱加热结果基本相同。青豆、黑豆与黄豆结果相近。结论加热使豆粉中部分糖苷型大豆异黄酮分解转化为苷元,活性成分增多,营养保健价值提高。     

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。     

里氏木霉β-葡萄糖苷酶水解大豆异黄酮糖苷的工艺研究

研究了里氏木霉β-葡萄糖苷酶的酶学性质,及其水解大豆异黄酮糖苷能力.该酶反应的最适温度为50℃,最佳pH为5.0;此酶在pH 4.5～5.5之间和低于60℃下酶较稳定,在80℃基本无活力.采用里氏木霉β-葡萄糖苷酶水解的方法,将大豆异黄酮糖苷转化为苷元,以染料木苷水解率为检测指标.通过正交试验确定了该酶水解大豆异黄酮的工艺条件为反应温度50℃、水解时间90 min、水解介质pH4.5、加酶量20U,大豆异黄酮中染料木苷的水解率为99%.     

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.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.