国外简讯

机械预缩机的新一代弹性橡胶毯 据法国Rollin SA公司报道,其提供用于机械预缩机的TOP Shrink弹性橡胶毯具有使用寿命长,性能稳定,耐弯耐压,外观不易变形等优点。 织物机械预缩的均匀性和规一性,很大程度上取决于织物本身的性质和采用的预缩方法、预缩机和弹性橡胶毯。 织物在湿热状态下,通过弹性橡胶毯粘附性能的连接作用,使经纬密度增加,实现机械预缩。然后当织物离开预缩机时,即刻烘干,使缩率永久固定。机械预缩还能改善织物的外观,如光泽和手感。 预缩过程可以分成二个主要步骤进行,预缩阶段,通过橡胶毯挤压,使织物预缩;热固阶段,通过橡胶毯和加热转鼓作用使织物缩率固定。 预缩的产生是由于弹性橡胶毯的挤压作用,降低了织物的运行速度,另一方面,使织物的纱线均匀滑移。     

牛仔布的预缩整理与回伸的研讨

通过对织物缩水机理的讨论,介绍防止织物缩水的预缩方法和橡胶毯预缩机预缩的原理。并针对橡胶毯预缩后存在的长度回伸和使用过程中裤缝扭转问题,提出解决办法。给针对制定工艺和织物标准提供参考和帮助。     

印染厂节能减排实用工艺装备技术(二十一)——织物缩水率的控制

(3)承压辊直径越小,预缩率越大 承压辊直径减小,橡胶毯的变形量随之增加,从而可达到较高的预缩率.但承压辊直径过小,织物在预缩区湿热定形的时间过少,影响预缩的稳定性;且橡胶毯会因挠曲次数增加产生疲劳而缩短使用寿命. 从目前使用情况来看,采用50mm橡胶毯,承压辊直径为Φ500mm;采用67mm橡胶毯,承压辊直径为Φ616mm. (4)布面及橡胶毯表面含湿量 ①预缩前织物的含潮率一般为10％-15％,织物的单位面积质量越大,含潮率也越大.纤维之间的水分是一种润滑剂,使纤维之间产生滑动而达到预缩效果. 织物经喷雾给湿后,再经过Φ570mm烘筒的烘蒸,是促使织物含潮均匀的一种常用方式.喷雾给湿时,可使用各种添加剂,但要注意,添加剂是一种润滑剂,既可以使织物收缩,也会造成织物伸长. ②橡胶毯表面的含湿量会直接对织物含湿量产生影响,一般可改变织物含湿率1％-3％.具体控制橡胶毯带水量主要有两个办法:一是选择不同号的砂带研磨橡胶毯,如60#带水量大,100#带水量小;二是改变压水辊压力大小,也可改变橡胶毯带水量.     

牛仔布超级防缩整理

介绍了用国产染整单机台设备，对牛仔布等厚织物进行防缩整理的生产工艺；探讨了橡胶毯预缩的原理和影响预缩效果的因素。     

橡毯式防缩机理论预缩率分析计算

本文论述了椽毯式防缩机的预缩机理以及推导了织物预缩率的计算公式;分析了影响织物预缩率的橡毯厚度、加压辊直径与承压辊直径各参数之间的关系。文章也述及了各种不同穿布路线下的收缩效果以及欲得到良好预缩率的操作要求和织物的前处理条件。     

针织物汽蒸式预缩机的设计原理

服装材料在加工制作过程中，经过织造、精炼、染色、整理等各种理化处理，由于在各道工序中所受的强烈的机械张力，导致织物内部存在着不同的应力和其它病疵，这种情况若在制作服装前不加以消除，将会不同程度地影响服装产品的形态稳定性、穿着性能等。预缩整理正是消除和纠正这种影响的一种必要的工序，预缩机是具有对织物预缩整理功能的机械。预缩机的种类很多，通常有机械式的预缩机（如橡胶毯式、呢毯式、挤缩式等）；汽蒸式预缩机；超声波水汽雾化预缩机以及冷冻蒸发预缩机等。前一种预缩机（机械式）使用比较多，后两种预缩机由于结构…     

织物预缩整理的给湿与控制

针对织物在预缩整理中的给湿均匀性问题,介绍了预缩机对织物给湿的主要方式,即蒸烘筒给湿、甩盘给湿、扇形喷嘴给湿和橡胶毯自给湿,分析了工作原理和优缺点,并根据织物品种给出了适宜的工艺参数。     

YG801型伸缩比率计在防缩整理机上的应用

织物“缩水”的稳定性,是评定织物质量的重要指标之一。采用机械预缩整理法,使织物预缩后达到降低缩水率的要求。织物的预缩效果是以织物预缩前后的缩率来衡量。织物预缩率的多少和三辊橡毯预缩装置的橡毯厚度和张力、进布加压辊和加热承压辊之间的间隙、加热承压辊的直径和温度、织物含湿率及车速等因素都有密切关系。由于影响织物预缩率的参数颇多,要了解经调整某参数后,预缩率的变化情况必须进行人工测定。     

Monforts:新型预缩整理机提升预缩效果

德国Monforts公司展示了一台全新设计适用于机织物(Mon-fortex)和针织物(Toptex)的机械抽缩式预缩整理机,提供了更高的最大收缩率和更快的生产速度,可自动打磨橡胶毯,减少了冷却水消耗,并大大节省了更换橡胶毯的时间.     

影响织物预缩率的重要因素分析

介绍了橡毯预缩机的预缩原理,着重分析影响织物预缩率的因素。     

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.