超声波辅助提取莲子心总黄酮的响应面优化

研究超声波辅助提取莲子心总黄酮的最佳工艺条件。单因素试验考察乙醇体积分数、超声温度、超声功率、料液比、超声时间对总黄酮提取得率的影响,在单因素试验基础上,采用Box-Benhnken响应曲面法考察乙醇体积分数、料液比、超声温度及其交互作用对总黄酮得率的影响。利用软件Design Expert 6.0.1对试验数据进行回归分析,得到二次多项式回归方程预测模型。结果表明,莲子心总黄酮的提取工艺最佳条件为乙醇体积分数80%,料液比1∶16(g/m L),超声温度50℃,超声功率120 W,超声时间20 min,此条件下总黄酮的提取得率为3.071 5%,与预测值基本一致。     

芡实叶黄酮超声提取工艺优化

通过Plackett-burman设计法研究料液比、超声功率、乙醇体积分数、提取温度和时间5个因素对芡实叶黄酮提取效果的影响,选择影响效果较显著的4个因素——料液比、超声功率、乙醇体积分数、提取时间通过正交试验优化得出超声提取芡实叶黄酮最佳工艺条件为料液比1:25(g/mL)、超声功率175W、乙醇体积分数85%、提取时间40min,在此条件下芡实叶黄酮提取量为90.28mg/g。     

超声波提取枣树皮中总黄酮的条件研究

采用超声波法提取金丝小枣枣树皮中的总黄酮。通过单因素试验研究了料液比、乙醇体积分数、提取时间、超声功率和超声温度等因素对总黄酮提取率的影响,并进行了四因素三水平正交试验,确定了枣树皮总黄酮的最佳提取条件。结果表明:最佳提取条件为料液比1∶15(g/m L),乙醇体积分数50%,提取时间50 min,超声功率342 W,提取温度70℃,提取两次。此条件下总黄酮的平均提取率为5.53%。     

正交实验法优化枣核黄酮的超声提取工艺研究

采用正交实验法优选枣核中总黄酮的最佳超声提取工艺。以芦丁为对照品,采用分光光度法进行测定,以枣核中黄酮含量作为考查指标,通过单因素实验研究超声波功率、提取时间、提取温度、料液比和提取溶剂乙醇体积分数对提取效果的影响,再利用正交实验法优化最佳提取工艺条件。结果表明,对枣核黄酮提取影响的大小次序为提取温度>料液比>提取时间>乙醇体积分数>超声波功率,最佳提取工艺为:提取温度55℃,料液比为1:50,提取时间为40min,乙醇体积分数为50%,超声波功率为400W,在该条件下枣核黄酮粗品的提取率为12.45%,粗品中黄酮含量为6.83mg.g-1,能显著提高枣核黄酮的提取效率。     

超声辅助提取桂皮中总黄酮的工艺研究

以桂皮为原料,以总黄酮提取率为指标,研究了采用超声辅助提取桂皮中总黄酮的工艺,分别研究了乙醇体积分数、料液比、超声时间、超声温度对黄酮提取的影响,并通过正交试验优化了提取工艺。总黄酮提取的最佳工艺条件是：乙醇体积分数70％、料液比1：35、超声时间30min、超声温度65℃,在此最佳条件下总黄酮提取率可达8.31%.     

超声波法提取紫薯茎叶中总黄酮的工艺优化

以紫薯茎叶为实验材料,采用超声波辅助溶剂法提取其中的总黄酮,考察液料比、提取时间、提取温度、超声功率和乙醇体积分数对紫薯茎叶中总黄酮得率的影响。基于单因素实验,选取四个主要影响因素液料比、超声时间、超声功率、乙醇浓度,应用Box-Behnken响应面实验设计法优化工艺条件。研究表明,紫薯茎叶中总黄酮的最佳提取工艺条件是:液料比18:1 (mL/g)、提取时间50 min、超声功率200 W、乙醇体积分数75%,总黄酮实际得率为3.46%,与预测值3.51%相接近,研究结果为总黄酮的高效提取及紫薯茎叶的综合利用提供了参考。     

响应面法优化超声波辅助提取沙棘籽粕中黄酮工艺

研究了沙棘籽粕中黄酮的超声波辅助提取工艺。在单因素实验的基础上,采用响应面分析法对影响黄酮得率的超声功率、提取时间、液料比、提取温度、乙醇体积分数进行优化,建立了二次多项式回归方程的预测模型。结果表明:超声波辅助提取沙棘籽粕中黄酮的最佳工艺条件为超声功率60 W、提取时间20 min、液料比30∶1、提取温度54℃、乙醇体积分数59%、提取次数2次,在最佳工艺条件下黄酮得率为7.11%,与模型理论值7.08%基本一致。     

正交试验优化远志黄酮提取工艺研究

以中药远志为原料,通过超声辅助提取远志中的黄酮,借助正交试验优化黄酮的提取条件,确定因素影响顺序依次为乙醇体积分数提取温度料液比提取时间,终得到远志中黄酮最佳超声提取工艺条件为超声功率400 W、料液比1∶60 (g/m L)、提取温度70℃、乙醇体积分数100%、提取时间10 min。在此条件下,黄酮提取率最高为1.82%。     

无花果叶中黄酮的提取及其抗氧化活性测定

采用正交试验设计研究超声波辅助提取无花果叶中总黄酮的工艺条件,并对无花果叶中总黄酮的抗氧化活性进行测定。结果表明：无花果叶中总黄酮的最佳超声提取工艺为体积分数40% 乙醇溶液、料液比1:60(g/mL)、超声功率400W、超声温度60℃条件下提取50min,其提取量为25.04mg/g,影响无花果叶中总黄酮提取效果的主次因素为：超声温度＞超声时间＞料液比＞乙醇体积分数。无花果叶黄酮提取物具有清除羟自由基、超氧阴离子自由基的作用,其清除效果在一定范围内随着总黄酮质量浓度的增加而增强。     

枣核总黄酮的微波辅助提取工艺优化

目的：采用正交试验法,优选枣核中总黄酮的微波辅助提取工艺。方法：以芦丁为对照品,采用分光光度法进行测定,以枣核黄酮提取率作为考查指标,对影响黄酮提取工艺的因素进行研究。通过单因素试验研究微波功率、提取时间、提取温度、料液比和提取溶剂乙醇体积分数对提取效果的影响。然后,利用正交试验法优化最佳提取工艺条件。结果：对枣核黄酮提取的影响程度大小顺序为料液比＞提取温度＞提取时间＞乙醇体积分数＞微波功率,正交试验结果表明最佳提取工艺参数为料液比1:60(g/mL)、提取温度60℃、乙醇体积分数50%、提取时间20min、微波功率500W。在最佳工艺条件下,枣核黄酮粗品的提取产率为10.14%,粗品中黄酮含量为7.00%。结论：采用正交试验-微波提取工艺,能显著提高枣核黄酮的提取效率,具有较好的提取效果。     

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.     

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.     

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.     

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.