分子蒸馏技术分离米糠活性物质二十八烷醇的研究

二十八烷醇主要来源于动物蜡和植物蜡,米糠蜡和蔗蜡是其最大来源。二十八烷醇的提取与分离传统上采用高真空分馏法,可获得纯度50%的二十八烷醇产品,但分离效果和效率不太理想。采用分子蒸馏技术可以明显提高二十八烷醇分离效率,提高产品纯度。在薄膜蒸发器温度为170℃,分子蒸馏器温度为210℃的条件下,可获得纯度为52.6%的二十八烷醇产品,分离时间和分离效果明显优于传统方法。     

以蔗蜡为原料制备及纯化二十八烷醇

以蔗蜡为原料,采用醇相皂化法制备长链脂肪醇,通过重结晶法获得高纯度二十八烷醇,采用毛细管气相色谱测定各阶段产物中二十八烷醇含量,实验结果表明:长链脂肪醇的得率为24%,其中二十八烷醇含量为66.50%,经分离纯化后的小试样品中二十八烷醇含量为88.96%。     

二十八烷醇研究进展

二十八烷醇开发与应用是当今保健食品研究与开发新热点,该文介绍二十八烷醇的来源、理化性质、生理功能及提取方法;综述二十八烷醇在食品、化妆品、饲料和医药等领域应用进展。     

二十八烷醇的研究状况及应用

本文主要讨论了二十八烷醇的国内外研究状况，二十八烷醇的生产工艺和分析检测方法，以及二十八烷醇的在食品中的应用。     

二十八烷醇的生理功能与应用进展

研究表明,二十八烷醇具有抗疲劳、促进新陈代谢、抗动脉粥样硬化、防治帕金森综合症和阿兹海默病等多种生理功能。本文主要综述了二十八烷醇的理化性质、生理功能、分布与提取方法,并展望了其应用前景。     

二十八烷醇研究进展(上)

近年来对二十八烷醇的应用研究越来越重视,本文对它的物理化学性质、在自然界的来源与分布概况、生物和生理功效、制备、分离及提纯方法、分析方法等进行了综述,对二十八烷醇在食品、饮料和医药行业的应用也进行了简单的介绍.     

气相色谱法测定糠蜡提取物中的二十八烷醇和三十烷醇

采用毛细管气相色谱法测定糠蜡提取物中的二十八烷醇和三十烷醇的含量。结果表明，在HP-5柱上，二十八烷醇、三十烷醇与其它种类高碳脂肪醇和内标物三苯基苯之间有较好的分离效果。方法的线性范围均为100～900mg／ml。该法简便、准确性和精密度好，对同一试样的4次平行独立测定的相对标准偏差(RSD)分别为0．86％和0．76％。     

米糠蜡在超声条件下制备二十八烷醇的研究

在超声波强化条件下通过化学酯交换工艺从精糠蜡中提取高碳脂肪醇。研究了超声波功率、反应时间、蜡醇比、反应温度以及催化剂用量对二十八烷醇提取效果的影响。通过正交实验,确定了最佳的酯交换工艺参数：超声波功率200W,反应温度60℃,蜡醇比1：10,反应时间6h,催化剂用量1．5％。在此条件下,酯交换产品得率为85．82％,其中二十八烷醇含量为14．68％。与传统酯交换工艺相比,在超声波条件下酯交换反应得到强化,缩短了反应时间,提高了反应产物得率和二十八烷醇含量。     

酯交换法从蔗蜡中提取高碳脂肪醇的研究

研究探讨酯交换法从蔗蜡中提取高碳脂肪醇的工艺条件,通过正交试验,得出最优工艺条件:以丁醇为溶剂,料液比为1:15,反应时间为4 h和0.1%KOH醇溶液为催化剂,此时高碳脂肪醇的得率为:16.75%～17.34%.通过GC-MS对高碳脂肪醇分析检测,二十八烷醇含量为67.09%.     

二十八烷醇O/W乳状液稳定性的研究

二十八烷醇是一种高级饱和长链脂肪醇,水分散性差.通过实验,建立了二十八烷醇O/W乳状液配制方法,对不同食品添加剂对其稳定性的影响进行了详细研究.结果发现,低浓度一价盐、二价盐、糖、有机酸和氨基酸使二十八烷醇乳状液的稳定性上升.     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.