无机陶瓷膜超滤大豆混合油脱胶的研究

用截留分子量1万的无机陶瓷膜在45℃、0.15 MPa下超滤大豆混合油,研究了膜通量与浓缩比的关系.超滤脱胶结果表明,超滤可以脱除95.78%的大豆磷脂,同时超滤脱胶油的色泽和毛油色泽相比,明显变浅,但是酸值升高.超滤还可以截留大豆油中的Ca、Mg、Fe和Cu等金属元素.     

大豆混合油中磷脂反相胶束分子量分布的测定

用截留分子量为1、2、10、20万的无机陶瓷膜超滤浓度为24.7%(W/W)的大豆混合油,测定了不同膜管截留分子量在不同超滤温度的磷脂截留率.超滤温度为50℃时,截留分子量1万的膜对磷脂的截留率为98.3%.分析了大豆混合油中磷脂反相胶束的分子量分布和温度的关系.温度越高,磷脂反相胶束的分子量越大,越有利于超滤脱胶的进行.     

无机陶瓷膜超滤澄清酱油的研究

用10、50、100nm孔径的无机陶瓷膜超滤酱油以除去其中的大分子蛋白质,澄清酱油以消除二次沉淀的现象。研究了不同孔径无机陶瓷膜超滤酱油,膜通量与超滤温度和超滤时间关系。选择用50nm孔径无机陶瓷膜管,在40℃左右超滤澄清酱油,可以解决酱油二次沉淀问题,并且稳定的超滤膜通量超过了100L/m2.h。碱液可以很好的清洗无机陶瓷膜管,恢复其超滤能力。     

无机陶瓷膜对大豆混合油净化的研究

通过无机陶瓷膜进行大豆混合油净化的研究,结果表明:选择30~100 nm无机陶瓷膜,在大豆混合油体积分数27.5%、温度43~50℃、真空0.07 MPa条件下,膜通量为562~1 178 L/(m2·h),除杂效果明显,除杂率达100%;100 nm孔径的无机陶瓷膜反洗通量衰竭较快,并有堵塞现象,不宜用于大豆混合油的净化;30 nm孔径的无机陶瓷膜与50 nm孔径的相比,膜通量小,投资增加,50 nm孔径的无机陶瓷膜过滤具有较合适的效果。     

混合油无机陶瓷膜微滤除杂制备食品级浓缩磷脂的研究

用2．4μm、3．0μm、4．2μm的无机陶瓷膜微滤除去大豆混合油中的杂质，此混合油经蒸发脱溶、水化脱胶、离心分离、浓缩干燥得到大豆浓缩磷脂的乙醚不溶物含量小于0．01％。同时研究了6号溶剂微滤膜通量和膜孔径及过滤压力的关系。结果表明：在过滤压力一定的情况下，溶剂的膜通量随着膜孔径的增大而增加。在0．30MPa过滤压力下，30％(V％)浓度的混合油微滤，其膜通量也随着膜孔径增大而增加。     

膜分离技术在棉籽糖糖液纯化中的应用研究

无机陶瓷膜具有优良的耐高温、耐酸、耐碱能力,采用无机陶瓷膜对棉籽糖液中所含的蛋白质等大分子物质可以进行有效脱除。通过研究发现,以0.005μm的陶瓷有机膜作为试验用膜,采用料液温度50℃,ΔP小于0.12MPa,浓缩比4.5,操作时间120～150min,蛋白质脱除率可达到87.4%,而透过液中棉籽糖含量没有变化。     

膜分离技术在棉籽糖糖液纯化中的应用研究

无机陶瓷膜具有优良的耐高温、耐酸、耐碱能力，采用无机陶瓷膜对棉籽糖液中所含的蛋白质等大分子物质可以进行有效脱除。通过研究发现，以0．005μm的陶瓷有机膜作为试验用膜。采用料液温度50℃，△P小于0．12MPa，浓缩比4．5，操作时间120～150min，蛋白质脱除率可达到87．4％，而透过液中棉籽糖含量没有变化。     

无机陶瓷膜在茶油精炼中的研究

目的:为解决传统油脂精炼方法存在的问题,研究无机陶瓷膜技术在油脂精炼中的应用。方法:从无机陶瓷膜的截留分子量、压力、温度和混合油浓度研究磷脂、色泽、酸价和膜通量的影响。结果:最佳膜技术处理工艺条件为陶瓷膜2万、压力0.3MPa、温度40℃、混合油浓度50%,经过处理,磷脂含量降到6.86mg/kg,色泽为Y5.2(25.4mm比色槽),酸价为0.63。结论:无机陶瓷膜技术应用到油脂精炼中,可简化油脂精炼工艺、减少能耗、降低生产成本、节省脱色吸附剂的用量,达到脱胶、脱酸和脱色的目的。     

乳酸杆菌无机陶瓷膜微滤浓缩条件的研究

采用无机陶瓷膜管微滤技术浓缩乳酸杆菌发酵液。实验中比较了不同膜管孔径、膜管面积、操作压力等对乳酸杆菌发酵液浓缩效果的影响。结果表明,选择无机陶瓷膜管孔径为0.1μm,膜面积为0.24 m2,操作压力为0.15 MPa,可得到体积浓缩5.6倍,活菌死亡比0.2,截留率达96%的乳酸杆菌浓缩液。无机陶瓷膜可用于乳酸杆菌发酵液的浓缩处理。     

几种澄清方法对梨汁理化和感官等指标的影响

本文研究了无机陶瓷微滤膜微滤、中空纤维超滤以及果胶酶对梨汁的澄清效果、理化及感官指标的影响。采用三种孔径的氧化铝膜和自制的加压微滤装置、外购中空纤维超滤装置以及果胶酶进行澄清实验。实验结果表明:(1)0.2μm孔径无机陶瓷膜微滤对梨汁的可溶性固形物含量、VC含量和还原糖含量影响不大,澄清梨汁得率较高,并且基本保持了梨汁的原有风味,适合梨汁澄清生产。(2)50nm无机陶瓷膜微滤和中空纤维超滤因孔径太小,不适合梨汁澄清生产。(3)0.8μm孔径无机陶瓷膜微滤和果胶酶澄清处理梨汁的浊度太大,短时间出现分层或沉淀,不适合梨汁澄清生产。     

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.     

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.