蛋白质和淀粉对面团流变学特性和淀粉糊化特性的影响

以3个筋力不同的小麦粉为材料,利用分离重组方法,在保持小麦粉其他成分不变的情况下,组成不同面筋蛋白和淀粉含量的配粉,研究面筋蛋白和淀粉添加量对面团流变学特性和面粉糊化特性的影响。结果表明：随着面筋蛋白添加量的增加,3种筋力小麦粉配粉的面团稳定时间和粉质质量指数均呈升高趋势,峰值黏度、低谷黏度、最终黏度、稀懈值、回生值等总体呈下降趋势。小麦粉添加淀粉后,面团稳定时间和粉质质量指数均呈下降趋势,峰值黏度、低谷黏度、最终黏度、稀懈值、回生值等总体呈升高趋势。面筋蛋白和淀粉对小麦面团吸水率和面粉糊化温度的影响均较小。不同筋力小麦粉配粉各品质指标总体变化趋势一致,但变化幅度有一定差异。     

不同出粉率小麦粉矿物质含量及其加工品质研究

为探讨不同出粉率小麦粉矿物质含量及其加工品质的变化规律,选取优质中筋小麦为原料,利用布勒试验磨粉机制备出粉率分别为66%,68%,70%,72%,74%,76%和78%的小麦粉,分析其矿物质含量及加工品质。结果表明,随出粉率的提高,小麦粉矿物质中钾、镁、铁、锌含量均显著升高(p0.05),而钙含量无显著变化;小麦粉灰分、粗蛋白、膳食纤维含量均显著升高(p0.05),而水分和粗淀粉含量显著下降(p0.05);小麦粉破损淀粉值、沉淀值、粉质吸水率均显著提高,而淀粉糊化的峰值黏度、低谷黏度、终值黏度显著降低(p0.05);面筋指数和崩解值呈先增大后减小的变化规律;面筋含量、面团形成时间和稳定时间无显著变化。研究可为充分利用小麦资源、提高面粉企业经济效益提供理论支撑。     

糯小麦配粉对小麦粉及面包品质影响的研究

采用不同的配比将糯小麦粉加入到小麦粉中,通过测定一系列小麦粉指标和面包指标,研究了糯小麦配粉对小麦粉及面包品质的影响.结果表明:随着糯小麦粉比例的增加,支链淀粉含量、支直比、湿面筋含量、沉降值、弱化度增加;直链淀粉含量、总淀粉含量、降落数值、形成时间与稳定时间下降;小麦粉的峰值黏度、最终黏度与回升值都逐渐降低,而糊化温度变化不显著;将5%～10%的糯性小麦粉添加到面包粉中生产面包,面包的体积与综合得分略有下降,但面包的吸水率与保水性能增加,抗老化性能有所增强,有利于面包货贺期的延长.     

不同精度对小麦粉品质及其面团特性的研究

将不同系统粉按照出粉率-灰分曲线配制成9种不同加工精度的小麦粉,对不同精度的小麦粉品质基本指标、糊化特性、粉质和拉伸特性进行分析对比,旨在寻找出不同精度小麦粉品质和面团特性的变化规律.结果表明:随着加工精度的降低,小麦粉灰分、蛋白质和湿面筋含量逐渐增加,粗淀粉含量和降落数值逐渐下降.小麦粉黏度值、形成时间、稳定时间和拉...     

微波处理参数对发芽小麦理化特性的影响

在实验室条件下研究了微波处理参数中辐照前的润麦时间及微波辐照时间对发芽小麦品质的影响。结果表明,微波处理能改善发芽小麦的品质。辐照时间为30~90 s时,对发芽小麦各项品质参数的改善不明显;辐照时间为180 s时,虽然能大幅度提高降落数值、峰值黏度和面筋指数,但对湿面筋含量、面筋水合能力均造成不利的影响。最大程度改善发芽小麦品质的微波辐照时间是120~180 s。润麦时间为30 min时,微波处理后发芽小麦的降落数值、峰值黏度没有显著性变化;润麦时间大于30 min时,微波处理后发芽小麦粉的湿面筋含量趋于稳定,但面筋指数逐渐增大。微波辐照前的最佳润麦时间是30~60 min。     

球磨处理对小麦淀粉理化性质的影响

该文以小麦淀粉为原料,采用行星式球磨机对小麦淀粉进行机械损伤,通过对不同球磨处理时间下小麦淀粉的损伤淀粉含量、沉降体积、析水率、透明度以及溶解度和膨润力等指标的测定,得出:随着球磨时间的延长,小麦淀粉的溶解度、膨润力、析水率和损伤淀粉含量均显著增加,淀粉糊的峰值黏度、谷值黏度、最终黏度、衰减值和回生值均呈明显下降趋势;凝胶的硬度、脆度、黏附性、弹性和咀嚼性也随球磨时间的增加而下降。     

超微粉碎对小麦粉品质特性影响的研究

为探讨超微粉碎对小麦粉品质及面团流变学特性的影响,提高小麦粉制作面制食品的适宜性,选取优质强筋小麦样品,采用布勒实验磨粉机进行研磨制粉,再利用气流粉碎机对小麦粉进行超微粉碎处理,得到6种不同粒度的超微粉碎小麦粉样品,分析超微粉碎小麦粉品质及面团流变学特性(粉质参数)。结果表明:随着小麦粉粒度的减小,湿面筋含量、干面筋含量、降落数值均显著降低,破损淀粉含量、沉淀值、吸水量均显著提高(P0.05);淀粉糊化的峰值黏度、面团稳定时间、粉质质量指数均呈先增大后减小的变化规律。当小麦粉颗粒粒径D_(50)由43.07μm减小至25.81μm时,其淀粉糊化的峰值黏度由136 RVU显著增加至149RVU;当小麦粉颗粒粒径D_(50)由43.07μm减小至15.22μm时,其面团稳定时间由10.6 min增加至14.8 min。因此,综合考虑超微粉碎对小麦粉蛋白质品质、淀粉品质和面团稳定性的影响,采用超微粉碎技术对小麦粉进行适度加工,粒度(D_(50))达到25μm左右时,可以显著改善其淀粉糊化特性与面团加工特性。     

不同粉路小麦面粉理化性质与流变学特性分析

以15个不同出粉口小麦粉为样品,采用宏观理化表征与微观显微技术相结合的方法测定其特性。结果表明:M粉的前中路易糊化,其峰值黏度、低谷黏度、最终黏度、稀懈值、回生值比较高,其次是B粉的前路,而M粉的后路、B粉的后路、XF粉与T粉糊化指标相对较低,品质较差。面筋蛋白含量高的小麦面粉的吸水率、形成时间、稳定时间和粉质质量指数也相对较高,面筋蛋白含量对面团稳定时间影响很大,但相同筋力不同粉路的小麦面粉变化幅度不同。旨在为提高面粉品质分析与控制提供理论依据。     

微波辐照对发芽小麦理化特性影响的初步研究

在实验室条件下研究了微波辐照对不同品种、不同发芽时间的小麦样品其理化特性的影响.结果表明,随发芽时间延长,小麦及小麦粉的降落数值减小,表征小麦粉糊化及黏度特性的指标(面糊峰值黏度、峰值温度、崩解值、回生值)降低,面团的耐搅拌特性弱化,稳定时间缩短.微波辐照改善发芽小麦品质的作用非常明显,尤其对发芽时间短的小麦样品,可以显著增加其降落数值和峰值黏度,增强面团的搅拌稳定性.研究结果初步证实了微波辐照改善发芽小麦品质的可行性.     

发芽状况及热处理对小麦淀粉品质量影响的研究

以面筋强度不同的7个小麦品种为材料,分析不同发芽状况与热处理对小麦淀粉品质的影响。结果表明：发芽使α－淀粉酶活性激增,表现为降落值（FN）、膨胀势下降。70℃、90℃处理的发芽小麦,较未经热处理芽麦的降落值、膨胀势增高,说明适当高温处理能降低α－淀粉酶的活性。发芽及热处理对小麦淀粉含量影响较小。面筋强度不同的小麦品种表现基本一致。     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press