聚乳酸纤维的低温染色工艺

聚乳酸纤维作为新型环保型纤维,具有良好的发展前景.由于聚乳酸纤维耐热性差,影响分散染料上染,还会影响纤维的其他性能如手感、断裂强力等.聚乳酸纤维染色温度的选择至关重要,约克夏染料在较低温度95℃时,上染率达到要求.上染时间长短对聚乳酸纤维的染色也尤为重要,在染色时间为30 min时,上染率达到最高值.在染液pH=5的条...     

影响超临界二氧化碳染色上染率的工艺参数

在生产型超临界二氧化碳染色样机上用分散红60对涤纶筒子纱进行染色,研究了各工艺条件(温度、压力、时间及染料浓度)对上染率的影响,从而获得优化的染色工艺.结果表明,上染率分别随温度、压力的增高而增大,且温度对上染率的影响更为显著;染料的上染服从能斯特分配关系;在120 ℃和25 MPa的超临界条件下染色60 min,可达到与水介质染色相当的染色深度.     

锦纶在超临界二氧化碳中的染色研究

在温度60-110℃、压力16—22MPa的超临界CO2试验条件下，对锦纶6和锦纶66织物进行染色，考察了影响超临界CO2染色的主要因素，测定了锦纶织物的耐摩擦牢度。试验结果表明，在一定压力下，染料的上染量随着温度的升高而增加，在100气左右上染达到平衡；在一定温度下，染料上染量随着压力升高而增加：相同条件下锦纶6上染量高于锦纶66；不同染色条件下超临界CO2染色锦纶的耐摩色牢度不低于水浴染色工艺。     

超临界CO2流体流速对涤纶织物染色的影响

超临界CO2流体的流速会影响染料在超临界CO2介质中对涤纶织物的上染性能和染色均匀性。通过研究在不同超临界CO2流速下的C．I．分散红60对涤纶织物的上染性能和匀染性的影响，得出其影响规律。     

聚乳酸/羊毛混纺纱一浴法染浅色工艺

为了缩短聚乳酸(PLA)/羊毛混纺织物的染色工艺流程,采用一浴法染色。对分散染料上染聚乳酸纤维的性能进行研究,结果表明:随着温度的升高,聚乳酸上染率增大,染色温度以100~110℃为最佳,染浴pH对上染率影响不大;而分散染料上染羊毛纤维时,随着温度的升高,羊毛上染率增大,染色温度为100~110℃、pH为4~5时染色效果较好;聚乳酸/羊毛混纺织物分散染料一浴法染浅色的优化工艺为:染浴pH=5左右,染色温度100~110℃,保温时间40 min。     

超临界条件对分散染料染色性能影响的研究

通过改变超临界条件系统，研究分散蓝79以超临界流体为介质对涤纶织物的上染性能。结果表明，温度和压力都对分散染料的上染性能有显的影响；分散蓝79宜在120～130℃、20MPa的超临界状态下染色；染色60min，上染已接近平衡，且可以达到与常规高温高压法染色相同的染色牢度。     

聚乳酸纤维(PLA)染色工艺探析

通过试验对聚乳酸纤维的染色性能进行了分析探讨。试验表明,聚乳酸纤维染色所用分散染料的上染率存在较大差异,所使用的染料必须经过选择;染色过程中,在80～110℃时上染速率较快,必须控制升温速度;到达染色温度后,染色时间的增加对上染率的影响不是很明显,这对实际生产中色光的控制较为有利;当pH值为4时,PLA纤维的上染率和断裂强力均达到最佳,因此PLA纤维染色适宜的pH值为4左右．     

分散红54超临界CO2染色染料量对上染性能的影响

为解决涤纶染色耗水耗能大、污染严重等问题，利用超临界流体溶胀、传质速率快的特性，对涤纶进行超临界流体无水染色。在压力22 MPa，温度120℃，CO₂流量50 g/min，涤纶织物10 g的染色条件下，研究了不同量的分散红54对涤纶织物染色性能的影响。结果表明:染料质量分数为5%时，可以得到涤纶织物较大上染量36～38 mg/g;当染料量较大时，染色前期的染料量对上染量基本没有影响;而染料量较小时，染料量对上染量有着十分显著的影响，随着染料量的增加，上染量不断增加。     

超临界CO2流体对芳纶1313专用染料染色性能的影响

为研究超临界CO_2流体中温度对专用染料在芳纶1313上的染色性影响和超临界CO_2流体预处理对该类纤维在传统水浴中的染色影响,采用专用红SCF-ANBL染料在超临界CO_2流体内不同温度条件下对芳纶1313进行染色,同时对超临界CO_2流体预处理的该类纤维在传统水浴内进行染色。实验结果表明,专用红SCF-ANBL在超临界CO_2流体及传统水浴介质中对芳纶1313染色良好。当超临界CO_2流体温度在60～120℃内变化时,专用分散红SCF-ANBL染料具有优良的低温上染性能,但随温度升高其上染性提高缓慢。芳纶1313经超临界CO_2流体预处理后,其在传统水浴介质中的染色性能有明显提升。     

涤锦复合纤维织物超临界二氧化碳染色研究

超临界流体染色可以实现无水染色,从源头上解决染色工业废水问题。染色时不添加助剂,无需清洗和烘干。采用分散红15在自行研制的超临界染色设备上上染涤纶/锦纶超细纤维织物,染色时间为60 min,通过分析红外光谱探讨了染料对织物的上染作用,并用K/S值表征分散红15对混合纤维的上染效果。试验结果显示:在温度为110℃,压力为22 MPa的条件下,K/S值最大,染色效果最好;染色后,织物并未引入新的基团,保持了原有的性能;染色牢度均达到了4～5级,符合标准要求。     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.