白刺种子黄酮类化合物最佳提取工艺研究

本文通过单因素及正交实验探讨了白刺种子内黄酮类化合物的最佳提取工艺。实验结果表明:在提取温度80℃的条件下用70%乙醇回流提取3次,每次1.5h,料液比为1:6(W/V)。在此条件下,黄酮类化合物的得率最高。     

柴达木盆地唐古特白刺果油的响应曲面优化超声-微波协同提取工艺研究

研究超声-微波协同提取柴达木盆地唐古特白刺果油的工艺。以提取率为指标,通过单因素实验分别考察了提取剂种类、微波功率、超声功率、液料比和提取时间对白刺果油提取率的影响。利用Design-Expert软件设计正交实验,并用响应曲面优化法优化唐古特白刺果油的提取工艺,确定的最佳提取工艺参数为:微波功率490W,超声功率290W,液料比20∶1m L/g,提取时间8min。在此最佳条件下,唐古特白刺果油的一次提取率为5.71%±0.18%(n=3),与理论计算值5.91%基本接近,说明回归模型能较好地预测唐古特白刺果油的提取率。实验结果表明,超声-微波协同提取唐古特白刺果油具有提取率高、速度快、操作简便等优点,另外为唐古特白刺果的进一步开发提供了参考依据。     

唐古特白刺果浆中原花青素提取工艺及抗氧化性研究

用乙醇作为溶剂,对唐古特白刺果浆中原花青素的提取工艺进行了研究,并采用Smirnoff法、邻苯三酚自氧化法以及卵黄脂蛋白不饱和脂肪酸(PUFA)过氧化体系,对唐古特白刺果实中原花青素清除羟自由基(·OH)、超氧阴离子自由基(O2-·)以及抑制卵黄脂蛋白脂质过氧化(LPO)作用的效果进行了测定.,结果表明,原花青素提取的最佳条件是:以体积分数70%的乙醇,浆液比为1g:20mL,提取时间2h,提取温度60℃,此条件下提取液中原花青素舍量为0.0158mg/mL;在原花青素含量为0.632μg时,对自由基清除的顺序为O2-·>·OH,同时具有一定的还原力和抑制LPO的作用.     

福建余甘可溶性多糖提取工艺研究

为了开发福建余甘资源,对余甘中可溶性多糖的提取工艺进行了研究。在单因素试验的基础上,通过正交实验确定了余甘多糖提取最佳工艺是:采用南大余甘为原料,100℃下浸提5h,提取率达到1.18％。     

五味子多糖不同提取工艺的研究

以北五味子为原料,多糖得率为指标,研究水提法、酶法、超声波辅助法三种方法提取北五味子多糖,通过正交实验的方法分别研究了多糖的最佳提取工艺条件.结果表明:超声波辅助法提取五味子多糖得率大于酶法和水提法,其最佳工艺条件为:料液比1∶25,超声时间40min,超声功率600W,提取温度55℃,多糖得率为4.67％.     

超声提取菜籽饼粕多糖的方法研究

本文采用超声提取法，从菜籽饼粕中提取多糖，用苯酚-硫酸比色法测定菜籽多糖含量。探讨了影响多糖提取率的主要因素（提取时间、料液比、次数），并用正交设计实验确定最佳提取工艺。结果表明：超声提取饼粕中多糖的最佳工艺为时间75min，料液比为1：40，次数为2，多糖产率为1、99％；超声法具有提取时间短、节省溶剂、提取率高的特点。     

绿茶中提取茶多糖最佳工艺的优化

采用单因素实验和L9(34)正交实验对绿茶中茶多糖的提取工艺进行了研究,研究了料水质量比、浸提温度、浸提时间、浸提次数对茶多糖提取的影响。结果表明,影响茶多糖得率的主次因素为:料水质量比、浸提温度、浸提次数、浸提时间;最佳提取工艺条件为:料水质量比为1∶25,提取温度85℃,提取时间为90min,提取1次。在此最佳工艺条件下,茶多糖得率为1.92%。     

椰花汁多糖提取工艺的研究

研究椰花汁多糖的提取工艺.首先采用单因素实验研究料水比、温度、pH、提取时间对多糖提取率的影响;然后采用正交优化实验探讨椰花汁多糖提取的最佳工艺参数.结果表明,椰花汁多糖提取工艺的最佳条件为:料水比1:10、温度75%、pH8.0、提取时间120min,在此条件下粗多糖提取率为11.13%.     

莲子可溶性多糖提取工艺的研究

对莲子中的有效成分可溶性多糖的提取工艺进行了研究。在单因素试验的基础上，通过正交实验确定了莲子多糖提取最佳工艺，料液比1：15，浸提时间3h，浸提温度100℃，在此条件下提取率可达0．82％。     

白刺果皮中原花青素的提取工艺

采用微波辅助超声波提取法从白刺果皮中提取原花青素.通过单因素试验和正交试验得出提取白刺果皮中原花青素的最佳工艺条件,原花青素的提取率为11.58 mg/g.     

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.