秋橄榄果实多酚提取工艺研究

以野生秋橄榄为原料,采用4因素3水平正交试验设计对其果实多酚提取工艺进行了研究。结果表明,在检测的4个因素中乙醇浓度对秋橄榄果实多酚的提取效率影响最大,其次为料液比、提取温度和提取时间。在超声波功率为70%的条件下,果实多酚提取的最佳工艺参数为30%乙醇、1:20料液比、40℃、每次15 min。     

正交设计优选油橄榄叶中多酚的提取工艺

以油橄榄叶片为原材料,优选多酚的提取工艺。以焦性没食子酸为对照品,通过乙醇浓度、提取料液比、提取时间、提取温度4因素,以多酚提取率为指标,先通过单因素试验,然后采用正交试验优选提取工艺条件。最佳提取工艺条件为乙醇浓度为70%、提取料液比为1:30、提取时间为1.5 h、提取温度为70℃。在最佳条件下多酚的提取率为3.265%。表明该提取工艺简单、合理。     

基于高效液相色谱-三重四极杆质谱分析番石榴叶多酚组分提取方法的研究

目的优化番石榴叶多酚组分的回流提取条件,为其工业化生产提供参考。方法建立番石榴叶9种已知多酚的高效液相色谱-三重四极杆质谱分析方法,在此基础上,以已知多酚提取率为考察指标,对料液比、提取液中乙醇体积分数、提取温度、提取时间和筛网目数进行单因素试验,然后,在单因素试验的基础上,选择对多酚提取率影响较大的4个因素(料液比、乙醇体积分数、提取温度和提取时间)设计四因素四水平正交试验,确定最优提取工艺条件。结果番石榴叶多酚最优提取条件为:料液比1:25 g/mL,乙醇体积分数60%,提取温度70℃,提取时间3 h。最优提取条件下提取率为2.352 mg/g。结论建立的番石榴叶多酚组分液质分析方法有效、可靠,优化得到的提取方法提取率高、重复性好。     

正交设计优化芒果核仁多酚的微波提取工艺

研究在不同的实验条件下,芒果核仁中芒果多酚的微波提取率,确定最佳提取提取工艺。采用单因素试验、正交试验方法,以微波提取法提取红象牙核仁的芒果多酚,确定红象牙核仁芒果多酚的最佳提取工艺条件。影响芒果多酚提取工艺因素次序为:提取温度料液比乙醇浓度提取时间。最佳工艺为:70%乙醇,料液比(g∶m L)1:15,微波提取温度60℃,提取时间60 s。优化出的微波提取工艺条件稳定、可行。     

响应面法优化油橄榄叶中橄榄苦苷超声辅助提取工艺

目的:研究油橄榄叶中橄榄苦苷超声辅助提取最佳工艺条件。方法:选定甲醇体积分数、料液比和提取时间作为影响因素,以橄榄苦苷提取率为评价指标。在单因素试验的基础上,通过3因素3水平Box-Behnken试验,建立橄榄苦苷提取率的二次多项式回归方程,经响应面回归分析得到优化组合条件。结果:最佳工艺条件为甲醇体积分数93.5%、料液比1:25(g/mL)、提取时间26min。结论:油橄榄叶中橄榄苦苷提取率可达7.83%。     

超声波辅助提取苹果渣多酚工艺

研究了超声波辅助提取苹果渣中多酚的工艺,利用二次回归正交旋转组合设计考察了乙醇体积分数、料液质量体积比、提取温度、提取时间对苹果渣中多酚物质提取率的影响;试验结果表明,各因子对提取率的影响大小依次是提取温度＞料液质量体积比＞提取时间＞乙醇体积分数;最佳提取工艺条件是:乙醇体积分数50%、料液比1 g:20 mL、提取温度60℃、提取时间24min;此条件下苹果多酚的提取率为3.80 mg/g.     

银杏叶多酚超声辅助提取工艺及其对羟自由基的清除作用

以银杏叶为原料,采用超声辅助乙醇提取银杏叶多酚。在利用单因素试验对影响银杏叶多酚提取率的4个因素(乙醇浓度、料液比、提取温度和超声时间)考察基础上,以多酚提取率为响应值,采用Box-Behnken试验设计与优化,分析提取过程中工艺参数对提取率的影响,并以多酚对羟自由基的清除作用来衡量其抗氧化性。结果表明,银杏叶多酚的最佳提取工艺为:乙醇浓度74%、料液比1:25(g/mL)、提取温度62℃、超声时间30 min,在此条件下银杏叶多酚提取率为8.32%。所提取的银杏叶多酚对羟自由基的清除效果高于VC,且与浓度呈正相关。     

响应面法优化美味牛肝菌多酚的提取工艺研究

以美味牛肝菌为原料,研究不同液料比、乙醇体积分数、提取时间、提取温度和提取次数对多酚提取率的影响,并在单因素试验结果的基础上,通过响应面法优化美味牛肝菌多酚的提取工艺。结果表明,美味牛肝菌多酚的最佳提取工艺条件为:液料比37(mL/g),乙醇体积分数57%,提取时间90 min,提取温度45℃,提取2次,在此条件下多酚的提取率为1.33%±0.02%。试验结果为美味牛肝菌多酚的生物活性研究及功能调味料开发提供了一定的技术参考。     

响应面优化薏米多酚提取工艺

采用超声法提取薏米多酚,以没食子酸为标准品、福林酚为显色剂,比色法测定多酚含量。在单因素试验基础上,利用Box-Behnken响应面分析法对薏米多酚提取工艺中的各因素进行优化。结果表明:薏米多酚提取率影响因素为提取温度料液比提取时间溶剂体积分数;当溶剂体积分数63.2%、提取温度54℃、料液比1∶21.1(g/mL)、提取时间33.6 min时,薏米多酚提取率理论预测值为76.93 mg/100 g。最佳优化工艺条件下进行实验验证,薏米多酚提取率为72.75 mg/100 g,实测值与理论预测值之间具有良好的拟合度,回归模型切实可行,优化的工艺条件适合薏米多酚提取。     

响应面法优化花椒叶多酚提取工艺及其抗氧化活性

以花椒叶为原料,对花椒叶多酚提取工艺及其抗氧化活性进行研究.通过单因素试验分析料液比、提取温度、提取时间对花椒叶多酚提取率的影响,在单因素试验基础上,利用响应面法优化提取工艺.优化得到各因素最佳参数为料液比1:56(g/mL)、提取温度81℃、提取时间107 min,验证试验所得实际多酚提取率为4.63％,与预测值接近...     

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.