面筋蛋白与面条品质关系研究

通过分离添加方法研究面筋蛋白、麦谷蛋白、麦醇溶蛋白对面条质构品质影响。结果表明:添加不同量面筋蛋白、麦谷蛋白后,面条硬度、咀嚼性、粘合性增大,而添加麦醇溶蛋白却减小;麦醇溶蛋白赋予面条粘附性;麦谷蛋白能增强熟面条内部强度即耐煮性;面筋蛋白对拉伸特性影响最大。     

大豆粉对小麦面粉及面条品质影响的研究

为改善面粉及其制品的品质,研究了大豆粉对面粉色泽、温水面糊色泽、沸水面糊色泽的影响。同时,还研究了添加大豆粉对面条面絮粒度分布、面片色度、面筋指数以及面条品质的影响。结果显示:添加大豆粉的面粉白度值、亮度值增加;相对于干粉和沸水面糊,温水面糊的亮度值最大;添加大豆粉A比添加大豆粉B对色度及面筋指数的影响效果更显著,从经济效益及面粉的品质综合分析,大豆粉的适宜添加量为0.02%;添加大豆粉后面条的小颗粒面絮的含量增加,面条的吸水率显著升高,煮面时间增加而蒸煮损失率下降。大豆粉的添加量与面条硬度、咀嚼性、拉断力呈显著正相关,与弹性呈显著负相关关系。     

面条冷冻过程中蛋白质组分和二硫键的变化研究

研究不同冷冻时间下面条的品质变化,如清蛋白、球蛋白、醇溶蛋白、SDS可溶麦谷蛋白、麦谷蛋白大聚体等蛋白质组分的含量变化,并采用Ellman's试剂比色法研究了蛋白和麦谷蛋白大聚体中巯基和二硫键的含量变化.结果表明:随着冷冻时间的增加面条的硬度有显著下降,回复性变化不明显,拉伸力和拉伸距离呈减小趋势;清蛋白、球蛋白、SDS可溶麦谷蛋白的含量呈上升趋势,醇溶蛋白、麦谷蛋白大聚体的含量呈下降趋势;蛋白质分子中巯基和二硫键发生了相互转化,单位质量麦谷蛋白大聚体中二硫键的含量呈增大趋势.     

利用RILs群体分析小麦粉品质性状与面条品质的关系

利用132个小麦重组自交系群体(RILs),测定了不同群体小麦面粉蛋白品质性状、面条感官品质和面条质构特性,研究了品质性状与面条品质的相关关系,在此基础上,用逐步回归法筛选了影响面条感官品质和质构特性的关键因素,对影响面条品质的所有性状做了通径分析.结果表明,面筋指数、吸水率和干湿面筋含量是影响面条感官总评分的关键性状,而且面筋指数对总评分的直接效应正向最大;面筋指数、面团形成时间和干湿面筋含量是影响面条硬度的关键性状,面筋指数的直接作用和间接作用均为正向较大,与硬度呈极显著正相关关系;吸水率和蛋白质含量是影响煮熟面条最大拉力的关键性状,蛋白质的作用大于吸水率.面筋指数极大地影响着面条品质.     

脂类对白盐面条品质的影响

将大豆粉末磷脂、亲水单甘酯、由面粉自身制出的游离脂和非极性脂按1%的含量加入到经石油醚脱脂的面粉中,研究其对面条品质的影响。结果表明:4种生面条硬度变化不明显,弹性逐渐减小,黏聚性和回复性显著增大;拉伸力和拉伸距离显著减小。4种熟面条中,添加非极性脂的熟面条硬度和回复性均显著增大,而其他3种脂对熟面条的TPA指标影响差异不显著;拉伸力和拉伸距离变化不明显。4种面条的最佳蒸煮时间显著减小,蛋白质损失率和干物质损失率逐渐增大,干物质吸水率先增大后减小。电镜实验中,4种生面条内部结构存在差异。     

SPI与SPH及其复配产物对面团特性和面条品质的影响机制

为提高面制品的营养品质,研究并比较了添加大豆分离蛋白(soy protein isolate,SPI)、大豆水解蛋白(soy protein hydrolyzates,SPH,水解度为4.54%)以及SPI和SPH复配产物(SPI-SPH)的混合粉的面筋特性和粉质特性,面团的动态流变学特性、蛋白质组分、二硫键和非共价键变化,以及面条的品质变化。添加SPI后面粉的湿面筋含量升高,干面筋含量下降,面筋指数降低,粉质特性评价值升高;面团的醇溶蛋白和麦谷蛋白含量增加,黏弹性增大,弹性比例增加。添加SPI-SPH的面粉面筋特性和面团特性变化趋势与添加SPI的面粉一致,其粉质特性评价值增大。添加SPH的面粉中无面筋洗出,粉质特性评价值升高;面团盐溶蛋白含量显著增加(P<0.05),弹性比例降低。添加大豆蛋白的面团中二硫键含量均增加,疏水相互作用减弱,氢键增强。与原面粉面条相比,SPI面条的硬度增大10.82%,SPI-SPH和SPH面条的弹性分别减小7.23%和6.02%,且添加SPH后面条的蛋白质保留率由93.02%降至87.31%。研究表明,大豆蛋白与面筋蛋白通过二硫键交联以及非共价键相互作用,阻碍面筋网络形成,破坏了面筋网络的连续性。并且,SPI和SPH复配在一定程度上减弱了SPH对面筋的弱化作用。     

青稞粉对速冻面条品质的影响

探讨不同青稞与麦芯粉比例对速冻面条品质的影响。以麦芯粉为对照样品,研究青稞粉对速冻面条品质的影响。结果表明:随着青稞粉混合面粉比例增大,混合面粉面团湿面筋含量逐渐下降,面团形成时间和吸水量逐渐增大;速冻面条品质与青稞粉添加量之间有良好的相关性,青稞粉添加量与面团形成时间、面团吸水量、干物质损失率、咀嚼性呈极显著正相关(P0.01);与湿面筋含量呈极显著负相关(P0.01),与冻融稳定性和TPA弹性呈显著负相关(P0.05);青稞与麦芯粉比例在1∶5~1∶7范围内,速冻面条蒸煮品质和冻融稳定性得到了明显的改善,面条煮后硬度下降,弹性上升,感官品质较好。青稞粉与麦芯粉比例为1∶6时,速冻面条品质最佳。     

小麦胚乳中直链淀粉含量分布及其对面条品质的影响

在同一生产线上对同一品种小麦按加工系统取制面粉样品,测定各粉样的直链淀粉含量;选择部分样品在其中添加整个粉路中最具代表性的系统面粉制成的谷朊粉,使各样品蛋白质含量相等、质量接近,在这种的前提下,研究直链淀粉含量对面条品质的影响。研究结果表明,小麦胚乳中,越接近皮层的部位,直链淀粉含量越低;越接近麦心的部位直链淀粉含量越高。小麦胚乳中的淀粉总量与面条品质无明显的相关性,而直链淀粉及支链淀粉含量对面条品质影响较大。直链淀粉含量与面条感官评价的表观状态、适口性、韧性、黏性、光滑性、食味及总评分都呈极显著负相关;与面条的煮制特性的干物质吸水率、蛋白质损失率和干物质损失率呈极显著正相关;而与面条质构仪TPA测定参数的黏合性、硬度和咀嚼性呈极显著负相关。     

重庆小面的面粉品质与面条特点之间的关系

对重庆市场销售的7种用于制作重庆小面面粉的理化性质及面条特性进行了研究,并与3种家用普通面粉,3种兰州拉面专用面粉及其制作的重庆小面进行了比较分析。归纳总结了重庆小面面条特点与制作其面粉品质之间的关系。结果表明,与普通家用面条面粉和兰州拉面专用面粉相比,重庆小面面粉蛋白质、湿面筋含量较低,其中麦谷蛋白含量较低,麦醇溶蛋白含量较高。因此面条内部面筋网络结构偏柔,硬度、弹性、筋道性较差,黏度较大,面条质地柔软适口,容易咬断。与另外2种面粉相比,重庆小面面粉的直链淀粉含量较高、膨胀势较大、峰值黏度和峰值时间较小,加之其面粉的蛋白质特性使得重庆小面在煮制时大量吸水膨胀和糊化,面筋结构易被破坏,面筋网络中包裹的淀粉颗粒容易溶出,因此其蒸煮吸水率及干物质、蛋白质损失率高。而淀粉颗粒溶出后,面筋网络中存在更多的空隙,重庆小面质地变得柔软不紧致,使得更多的调味料被吸附到面筋网络空隙中,加之面条表面黏度较大,调味料更容易黏附在面条表面,造就了重庆小面面条的赋味能力出众。     

高速连续和面机的和面效果及其对面条质量的影响

为了明确不同输料方式和搅拌速度的高速连续和面机的和面效果及其与间歇式和面机的差异,以3种小麦粉(高筋一等粉、富强粉、上白粉)为原料,采用2种高速连续和面机和1种双轴卧式和面机和面,分析和面效果及面条质量。试验结果表明,3种和面方式的和面效果存在较大差异,对面条质量影响显著。与2种高速连续和面机相比,采用双轴卧式和面机,面絮胚粒粒径较小,鲜面条拉伸特性较好,干面条烹调损失和吸水率较低,熟面条质地紧实、咀嚼性好,然而复合后的面片色泽偏暗。2种高速连续和面机的输料方式和搅拌速度不同,其制品质量差异显著。采用和面方式Ⅲ(水平输料、搅拌速度1 440 r/min),3种小麦粉面絮的中等粒径胚粒比例均显著小于和面方式Ⅱ(纵向输料、搅拌速度970 r/min),上白粉面絮的大颗粒(粒径≥4 000μm)胚粒比例显著较高,高筋一等粉面絮的水分均匀性和富强粉面片的色泽b*值均匀性较差。然而,其面片色泽较好,白且光亮,鲜面条拉伸特性也优于和面方式Ⅱ。2种连续和面机制作的面条质构也存在显著差异,然而对于不同品质的面粉,其差异表现不同。高筋一等粉和富强粉的蛋白质和湿面筋含量较低、颗粒较大,采用和面方式Ⅱ,其干面条烹调损失显著小于和面方式Ⅲ,其熟面条硬度、胶着性、咀嚼性显著较高;而对于蛋白质和湿面筋含量较高,颗粒小的上白粉,采用和面方式Ⅲ,其干面条烹调吸水率较低,熟面条质地更紧实。     

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