改性牛蹄油制备聚合物加脂剂及其应用的研究

用不同用量的醇胺和马来酸酐分两步改性牛蹄油 ,并用改性牛蹄油与丙烯酸共聚制备聚合物加脂剂 ,通过正交试验探讨油 /酸、温度、过氧化苯甲酰 (BPO)和低碳醇用量对合成反应的影响 ,得到最佳条件 :n (油 )∶n(丙烯酸 ) =1∶1 ,反应温度为 85℃ ,BPO用量是单体质量的 0 .5 % ,醇用量是单体质量的 2 0 %。将其用于铬鞣革复鞣加脂 ,材料吸收率和成革增厚率高 ,革柔软、粒面细致、富有油感、弹性 ,具有一定防水性 ,用于铬鞣中。试验表明 :有助于铬的吸收 ,不降低收缩温度 ,使铬鞣革更加柔软。     

乙烯基类单体改性铬鞣革屑水解产物制备复鞣填充剂的研究

以制革厂产生的固体废弃物铬鞣革屑为原料 ,在不脱铬的情况下对铬鞣革屑进行水解 ;用乙烯基类单体对铬鞣革屑水解产物进行改性 ,制备皮革用复鞣填充剂 ;对改性产品以茚三酮法进行分析 ,对铬鞣革屑水解产物及其改性产品进行IR分析和氨基酸分析。结果表明 :乙烯基类聚合物分子链以共价键在胶原蛋白水解产物的分子链 (即多肽链 )上发生了接枝 ;所制备的复鞣剂是一种含铬的蛋白复鞣填充剂 ,经其复鞣后的坯革 ,具有较好的伸长率和伸展高度     

鞣后湿操作过程中不浸酸铬鞣革的铬释放研究

通过与常规铬鞣革对比,研究了不浸酸铬鞣革鞣后湿操作中的铬释放情况,同时还研究了不同复鞣剂对不浸酸铬鞣革鞣后铬释放的情况。试验结果表明:不浸酸铬鞣革在鞣后湿加工过程中铬释放总量为2 012.83mg/L,与常规铬鞣革相比减少了30.67%;尤其是中和过程中脱铬量仅为常规铬鞣革的32.55%;丙烯酸类复鞣剂、氨基树脂类复鞣剂可以明显降低不浸酸铬鞣在鞣后湿加工过程中的铬释放,其中大分子丙烯酸复鞣剂复鞣过程中铬释放量减少了79.93%。总之,不浸酸铬鞣剂可以与皮胶原蛋白牢固结合,从而降低皮革在鞣后湿操作过程中铬的释放量。     

生物基醛鞣剂在铬鞣革复鞣中的应用研究

为了拓展生物基醛鞣剂(BAT)在皮革制造中的应用范围,以铬鞣革为研究对象,通过与常用丙烯酸树脂复鞣剂(AR)和荆树皮栲胶(TUN)配合使用,并与戊二醛(GTA)在相同复鞣体系下的复鞣性能进行对比,系统考察了BAT在铬鞣革复鞣中的应用性能.结果表明:BAT与AR具有良好的兼容性,而与TUN则不能同时加入.相较于GTA,单...     

一种多功能润滑型丙烯酸树脂鞣剂的研究

利用马来酸酐和 1 2、1 6、1 8醇合成马来酸单酯 ,确定n(酐 )∶n(醇 ) =1 .1∶1 ,温度 95～ 1 0 0℃ ,时间 3h ,马来酸1 2、1 6、1 8单酯的吸收率都高于 96%。用马来酸 1 8单酯与丙烯酸制备润滑型丙烯酸鞣剂 (MⅡ -1 8) ,通过正交试验 ,探讨酯 /酸、温度、过氧化苯甲酰 (BPO)和低碳醇用量对合成的影响 ,得到最佳条件∶n (酯 )∶n(酸 ) =1∶1 ,温度 80℃ ,BPO和低碳醇用量是单体质量的 0 .5 %和 2 2 % ,照此配方合成MⅡ 1 6/ 1 2。通过凝胶渗透色谱测定MⅡ分子量 ,数均分子量不超过 1 0 83 .1。将其用于铬鞣革的复鞣加脂 ,材料吸收率和成革增厚率高 ,革柔软、粒面细致 ,富有油感、弹性 ,具有一定防水性。用于铬鞣中的试验表明 :有助于铬的吸收 ,不降低收缩温度 ,使铬鞣革更柔软     

Retanal X-1噁唑烷鞣剂应用研究

分别采用新型双环噁唑烷复鞣剂(Retanal X-1)和戊二醛对黄牛蓝湿革进行复鞣,并结合合成鞣剂和荆树皮栲胶复鞣应用比较;用Retanal X-1对绵羊蓝湿革进行复鞣,并结合丙烯酸树脂复鞣剂复鞣应用比较。对复鞣后的废水总化学需氧量(COD)、总含铬量(TCr)、总含氮量(TKN)进行检测,测定坯革的物理力学性能以探讨Retanal X-1噁唑烷鞣剂的应用性能。结果表明,在黄牛革应用中,与戊二醛相比,Retanal X-1复鞣剂鞣革较软,并有较高的物理力学性能;加入合成鞣剂和荆树皮栲胶后,Retanal X-1复鞣革对铬的吸收增率约为39.7%;在绵羊革应用中,与其它两种丙烯酸复鞣剂相比,加入Relugan RE型丙烯酸树脂复鞣剂后的革物理力学抗性较好,Retanal X-1复鞣革对铬的吸收增率最高约为6.45%。实验结果表明,将Retanal X-1用于复鞣可增加成革对铬的吸收,使坯革物理力学性能提高。     

一种能增进铬鞣面革丰满性的鞣性树脂

美国专利3,206,435(1965.9.14)与3,397,941(1968.8.20)推荐了一种鞣性树脂。它是三聚氰胺、双氰胺、醛与有机磺酸中性盐的缩合反应产物。根据这种树脂作铬鞣面革复鞣后的成革质量特点介绍来看,可试用于酶脱毛铬鞣牛正面革工艺,以解决目前我们国内这种产品     

三聚氰胺羟甲基醇胺树脂鞣革研究

通过自制三聚氰胺羟甲基醇胺树脂(melamine-methylol-hydramine resin,MMH树脂)对多种物质的溶液的稳定性能测试,发现了MMH树脂对硫酸钠、植物鞣剂、明胶及合成单宁溶液敏感,在氯化钠、戊二醛溶液中稳定。研究了MMH树脂主鞣、多种复鞣及加脂的对比实验,获得了一些有意义的结果。单独MMH树脂鞣制绵羊酸皮可以获得收缩温度(Ts)为77℃。MMH树脂鞣制后进行醛、铬盐、栲胶(塔拉与荆树皮栲胶)复鞣,革的Ts都有增加。醛和铬复鞣革的撕裂强度都所增加,而植复鞣革的撕裂强度有所降低。主鞣和复鞣革加脂后的Ts都有下降。其中,未复鞣的革下降最大为6.45℃。经过加脂革的撕裂强度都有了一定程度的增加。扫描电镜表征了胶原纤维的组织构造。MMH树脂鞣制后有很好的纤维分散能力。经过复鞣纤维间距减小。减小的顺序是铬鞣、醛鞣和植鞣。     

意大利SILVATEAM(施华)公司系统介绍(续)

(上接2005年第7期)3·1WT白湿皮系统主要用于生产各种不是非常紧实挺身、柔软或者较为柔软类型的植鞣革或无铬鞣革,例如软包、沙发、服装、汽车用革等。该系统以SILVATEAM公司开发生产的LEDOSOL WT鞣剂为基础发展而成,通过用该鞣剂对酸皮进行预鞣,制得白湿皮,然后进行快速植鞣制成植鞣革,或者使用合成鞣剂、多种类型的复鞣剂制作白色或无铬鞣革。LEDOSOL WT鞣剂是改性的醛和特殊合成鞣剂的产品,具有较强的鞣性和渗透性,并有极佳的柔软效果,经过LEDOSOL WT预鞣的坯革,可以象铬鞣革一样直接进行后续的机械操作—挤水和削匀到…     

阴离子型水溶性聚氨酯类树脂复鞣剂与铬鞣革的相互作用

本文采用Ｘ－射线衍射，扫描电镜，热分析等方法研究了阴离子型水溶性聚氨酯类树脂复鞣剂与铬鞣革的相互作用及鞣制条件对鞣革性能的影响。试验表明阴离子型聚氨酯树脂复鞣剂可提高铬鞣革的收缩温度及力学强度。鞣制温度以４５℃为宜。     

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.