小麦麸皮结构层干法分离的初步研究

研究了干法分离麦麸结构层。首先对小麦麸皮进行微粉碎,通过粒径分析出麦麸粉体的粒径分散性最好的粉碎时间,利用旋振筛对此时的麦麸进行筛分,得到粒径不同的4种麦麸粉体,然后对各个麦麸粉体进行荧光定性和生化标示物定量研究。结果表明,筛分后,外皮层和中间层集中在200目筛上物的麦麸中,约占78.9%,麦麸糊粉层的细胞壁主要集中在200目筛下物和325目筛上物中,比例达41.7%,而小颗粒的麦麸糊粉层细胞内容物则集中在325目筛下物。研究初步表明,通过微粉碎和筛分的方法可以对不同麦麸结构层进行富集,为麦麸的深加工提供了一种简单的干法分离途径。     

地毯用抗静电剂的开发

当两种不同的材料相互接触而分离时,它们之间会产生静电,这种现象称为摩擦起电效应。按相互作用的强烈程度,可把各种材料排成一个序列,两种材料相距越远,摩擦带电量越多。许多因素都影响着电荷的多     

麦麸粒径对全麦面团流变学特性的影响

麦麸经不同强度超微粉碎后得到4种不同平均粒径(分别为327、209、144、45μm),将麦麸按照出粉率进行回添得到全麦面粉,以探讨不同粒度组成的麦麸对全麦面团流变学特性的影响。糊化特性分析结果显示随着麦麸粒径的逐渐减小,全麦面粉的峰值黏度、最低黏度、最终黏度和回生值等显著增大。粉质特征显示全麦面粉的吸水率随麦麸粒径的减小逐渐增大,但稳定时间减小、弱化度增大。拉伸仪结果表明醒发时间会影响麦麸粒径对面团面筋网络结构的作用,在面筋网络的逐步扩展和形成阶段(45~90、90~135 min),较小粒径的麦麸会促进面筋网络结构变得密实但降低了其延展性。动态流变学特征显示全麦面团的弹性模量和黏性模量随麦麸粒径的减小而减小,但在扫描范围内高于普通面团。由本研究结果可推测,麦麸粒径的减小会促进淀粉颗粒与麦麸层细胞的分离及麦麸纤维在面团中的分布,但增加了面团形成过程中的物理空间阻碍,干扰了蛋白质分子间的交联和面筋网络结构与淀粉颗粒的结合。      

麦麸粒径对全麦面团流变学特性的影响

麦麸经不同强度超微粉碎后得到4种不同平均粒径(分别为327、209、144、45μm),将麦麸按照出粉率进行回添得到全麦面粉,以探讨不同粒度组成的麦麸对全麦面团流变学特性的影响。糊化特性分析结果显示随着麦麸粒径的逐渐减小,全麦面粉的峰值黏度、最低黏度、最终黏度和回生值等显著增大。粉质特征显示全麦面粉的吸水率随麦麸粒径的减小逐渐增大,但稳定时间减小、弱化度增大。拉伸仪结果表明醒发时间会影响麦麸粒径对面团面筋网络结构的作用,在面筋网络的逐步扩展和形成阶段(45~90、90~135 min),较小粒径的麦麸会促进面筋网络结构变得密实但降低了其延展性。动态流变学特征显示全麦面团的弹性模量和黏性模量随麦麸粒径的减小而减小,但在扫描范围内高于普通面团。由本研究结果可推测,麦麸粒径的减小会促进淀粉颗粒与麦麸层细胞的分离及麦麸纤维在面团中的分布,但增加了面团形成过程中的物理空间阻碍,干扰了蛋白质分子间的交联和面筋网络结构与淀粉颗粒的结合。     

国外纺织品静电性能检测简述

简要介绍纺织品静电问题的产生，AATCC 84—1995、AATCC 76—1995、AATCC 115—1995和ASTM 4238-1990中静电性能检测指标和方法，以及静电检测中常用的摩擦起电和电晕充电方式，简述了静电衰减测试的重要性。     

微波和超声处理对麦麸研磨特性及全麦面团品质的影响

麦麸经过微波与超声处理后，研磨筛分成粗（280~450 μm）、中（154~180 μm）、细（≤71 μm）三种粒径，再将不同粒径麦麸回添至面粉中制成全麦面团，以此探究微波和超声处理以及不同粒径对全麦面团的全质构、动态流变学性质以及游离巯基的影响。麦麸的相对酶活与粒径分布表明，超声处理和微波处理均能较好提升稳定化效果和粉碎效率，且超声处理组的效果更好（P<0.05）。面团的品质显示，随麦麸粒径减小，微波处理组的硬度和胶黏性呈现下降趋势，内聚性呈现上升的趋势，超声处理组的硬度和胶黏性均小于微波处理组（P<0.05）；微波组弹性模量和黏性模量随着麦麸的粒径减小而减小，同种粒径时，超声处理组弹性模量和黏性模量均小于微波处理组；随麦麸粒径减小，各处理组的游离巯基含量逐渐降低，且超声处理组的游离巯基含量降低幅度大于微波处理组（P<0.05）。微波与超声处理及麦麸粒径的减小均能有效改善面团的品质，且超声处理的麦麸对面团品质影响相比微波组更显著。     

广佛手超微粉的制备及其理化性质分析

以广佛手为研究对象，用普通粉碎方式以及超微粉碎的方式制备不同粒径的广佛手粉（FC），并探究不同粒径粉体理化性质及其对多糖提取率的影响。实验结果表明，超微粉碎可以显着降低FC的粒径，延长超微粉碎时间，能减小粒径，使颗粒更细、更均匀，且经过超微粉碎的粉体其化学组成并不会发生改变。超微粉碎显著提升了粉体水溶性，降低了粉体持水性，粉碎后粒径大小对上述性质均有显著影响。粒径降低水溶性显著提升，持水性显著下降，粒径D50为20.01 μm的粉体水溶性高达64.49%，持水性仅有8.64%。在色泽方面，随着粒径降低，亮度值逐渐增大、红度值逐渐减小、黄度则先增大后减小。超微粉碎能在一定范围内提高广佛手多糖提取率，其中粒径D50为21.55 μm的广佛手超微粉多糖提取效率最高，达到了7.68%。该研究为广佛手的利用和新产品开发提供了一定的理论依据。     

基于DEM离散元建模技术的双轴桨叶式食品混合机运动仿真分析

目的：分析双轴桨叶式混合机内食品粉体颗粒的运动混合特性,优化验证混合机结构。方法：采用EDEM软件对3种不同尺寸的食品粉体颗粒按比例混合进行仿真,以后处理Bin Groups建立混合箱观察混合情况,并通过研究不同类型食品粉体之间的颗粒数量来进行评估。结果：在t=5 s时,3种粉体食品颗粒所对应的方格中颗粒数量还存在一定的差距,但是基本相差不大,3种粉体食品颗粒的混合程度已经很高;3种粉体食品颗粒之间的接触随时间的变化趋势大体上是相同的,随着时间的增加,各种粉体食品之间的接触数量也随之增加,待t=8 s之后,各种粉体食品颗粒之间的接触数量基本达到稳定值。结论：采用离散元法可以有效分析桨叶式混合机中粉体食品的混合情况。     

防电墙技术在淋浴器上的应用浅析

通过对浴室用电环境现状分析,发现电热水器的防电墙在一般情况下能起到防止漏电的作用,但是当进水源头带电时,电流会通过淋浴器混合阀冷水进水端直接传递到洗浴者,从而导致洗浴者触电受伤,此时电热水器端的防电墙起不到防电作用;因此提出了具有防电墙功能的淋浴器混合阀。介绍了防电墙技术的具体原理及实际应用;又针对具有防电墙功能的淋浴器混合阀进行实验分析,测试结果表明不管是热水进水端带电、冷水端带电还是冷水与热水端同时带电,经过带有防电墙功能的淋浴器混合阀之后,泄漏电流都在安全范围内,从而实现了浴室用电安全的升级。     

新型抗静电过滤布的开发

在对比其他抗静电方法的基础上,采用涤纶和锦纶交织交并工艺,利用两种纤维摩擦带电性能不同可以实现静电中和的特点,设计开发了适宜石油工业应用的一种新型抗静电过滤布。依照标准GB/T12703-1991对所开发的样品进行了检验,其摩擦带电量为0.46μC/m2,远远小于要求的7μC/m2的标准,抗静电效果较好。     

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.     

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.     

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.     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH₃CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH₂PO₄-20.6 mM Na₂B₄O₇ buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.