武陵山区4种块根类淀粉的糊化特性和冲调性质分析

目的:探究葛根、蕨根、百合、凉薯4种块根类植物淀粉的糊化特性与冲调特性。方法:采用扫描电子显微镜(SEM)、快速黏度分析仪(RVA)、差式量热扫描仪(DSC)等分析淀粉的微观形态和糊化特性;对4种淀粉进行冲泡,并分析淀粉糊的透明度和表观形态等。结果:葛根、蕨根、凉薯淀粉的颗粒形态较为相似,大多为球形;百合淀粉颗粒较大,且形态为纺锤形。糊化特性表明,百合淀粉的峰值黏度最高,为(7.00±0.03) Pa·s;葛根和百合淀粉的回生值较大,表明其易于回生。热力学特性表明,蕨根淀粉的起始糊化温度最低,为59.4℃,表明其容易糊化;百合淀粉的糊化焓值最高,为15.64 J/g,表明其糊化时需要更多的热量。冲调特性表明,葛根淀粉糊的透明度最好,其透光率为29.11%;而百合淀粉糊的透光率仅为12.25%;冲调后,葛根淀粉糊和百合淀粉糊易于形成凝胶,但流动性较差;蕨根淀粉糊和凉薯淀粉糊凝胶能力较差,易于流动。结论:百合淀粉和葛根淀粉的冲调性质相似,具有冲调类食品的开发潜力;蕨根淀粉和凉薯淀粉回生值较低,糊的流动性较好,可用于抑制食品的回生。     

DSC法测定水分含量对玉米淀粉糊化和老化特性的影响

建立差示扫描量热法(DSC)测定玉米淀粉糊化的方法,在升温速率和温度范围分别为10℃/min和45～95℃的条件下,研究不同水分含量对玉米淀粉糊化和老化特性的影响。结果证明玉米淀粉水分含量越高,其糊化需要的热焓越大;4℃贮存条件下,玉米淀粉老化快;水分含量越大,玉米淀粉老化速率越低。     

淀粉糊化过程中的物性变化

利用显微镜和旋转式黏度仪,研究木薯淀粉糊化过程中淀粉颗粒形态和溶液黏度的变化规律,从而探明原淀粉、阳离子淀粉以及两性淀粉糊化规律的差异性。结果显示:木薯原淀粉糊化的最佳温度是85℃,低取代度、中取代度和高取代度阳离子淀粉糊化的最佳温度分别是90℃、80℃和75℃,而低取代度、中取代度和高取代度两性淀粉糊化的最佳温度分别是85℃、90℃和70℃。淀粉在糊化过程中,随着糊化温度的升高,淀粉颗粒逐渐膨胀;而且改性淀粉的黏度都高于原淀粉。     

锥栗原淀粉及其分离组分的热力学特性

应用差示扫描量热分析仪研究了锥栗原淀粉、直链淀粉、中间成分和支链淀粉的热力学特性。4个样品在-50～350℃的程序升温过程包含冰晶融化(-10～5℃)、糊化(40～100℃)和熔融裂解(250～310℃)3个吸热过程。当水分质量分数为65%时,它们的晶体融化峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)均升至最高。对于相同的样品,当升温速率降低时,糊化温度向低温侧移动,且伴有肩状峰;糊化时升温速率越快,其凝胶体系的峰值温度(TP)、终止温度(TC)和吸热焓(ΔH)也越高,回生度越大;同样,糊化时降温速率越慢,凝胶体系的吸热焓(ΔH)增加,回生度增大。当糊化终止温度为100℃时,4个样品凝胶体系的DSC参数值均达到最低。锥栗原淀粉、直链淀粉、中间成分和支链淀粉凝胶体系的玻璃化转变温度(Tg)分别为-6.0、-7.1、-8.6和-7.9℃。     

部分糊化玉米淀粉浆液的制备及黏度性质研究

探讨部分糊化淀粉浆液的制备方法和黏度性质特点。以玉米淀粉为原料,分别采用恒温法和蒸汽升温法制备部分糊化淀粉浆液,研究了其浆液黏度和黏度稳定性,并采用正交试验分析了制备温度、浆液浓度和制备时间对其浆液黏度的影响。结果表明:蒸汽法64℃制备的部分糊化淀粉浆液具有黏度低(5 mPa·s~7 mPa·s)、黏度稳定性好、低温不凝冻、不分层等特点;影响部分糊化淀粉浆液黏度性质的因素从大至小依次为制备温度、浆液浓度和制备时间。认为:蒸汽法64℃制备的部分糊化淀粉浆液具有实际应用价值;制备黏度稳定且均一的部分糊化淀粉浆液需严格控制制备温度,其次为浆液浓度和制备时间。     

玛咖淀粉与马铃薯、淮山药淀粉的理化性质比较

以马铃薯和淮山药淀粉为对照,研究了玛咖淀粉的化学组分、颗粒形貌、结晶结构、热力学性质、溶解度、膨胀度、糊透明度和冻融稳定性。结果表明,玛咖淀粉颗粒呈现椭圆形或不规则形,颗粒长轴在7.2~15.6μm之间,短轴在5.1~9.8μm之间;其偏光十字呈现垂直交叉,X-射线衍射结晶结构为C型,且在衍射角(2θ)为20°附近有直链淀粉-脂类复合物的特征吸收峰。玛咖淀粉的颗粒形貌和结晶结构与淮山药淀粉相似。玛咖淀粉的糊化温度较马铃薯和淮山药淀粉低,该淀粉糊化的起始温度(To)、峰值温度(Tp)和终止温度(Tc)分别为46.88℃、50.42℃和54.82℃,糊化焓变7.37 J/g。玛咖淀粉的溶解度和糊透明度比淮山药淀粉高,比马铃薯淀粉低;其峰值黏度与山药淀粉相近,显著低于马铃薯淀粉;膨胀度和冻融稳定性均优于马铃薯和淮山药淀粉。玛咖淀粉作为一种淀粉新资源,具有一定的开发价值和广阔的发展前景。     

利用差示扫描量热仪研究小米淀粉及小米粉的糊化特性

采用差示扫描量热仪（differential scanning calorimeter,DSC）研究NaCl添加量、蔗糖添加量及pH值对小米淀粉和小米粉糊化特性的影响,并用SPSS软件进行相关性及显著性分析,将小米淀粉和小米粉的糊化特性进行对比。结果表明：相同测试条件下,小米淀粉的糊化温度（包括糊化起始温度T0、峰值温度Tp、糊化终止温度Tc）比小米粉糊化温度低（2.65±0.87） ℃;糊化热焓值（ΔH）比小米粉高（2.51±0.32） J/g;添加NaCl的小米淀粉及小米粉的糊化温度比添加蔗糖的糊化温度高（4.30±1.24） ℃。酸性条件抑制小米淀粉的糊化作用,碱的存在则促进体系糊化。     

薏米难糊化的机理研究

以糯米为参照,测定薏米的营养成分、淀粉颗粒大小、淀粉的热特性、结晶度和支链淀粉分子链长分布等指标,研究薏米难糊化的机理。研究结果表明:薏米的淀粉含量和水分含量均极显著低于糯米(p<0.01),蛋白质含量极显著高于糯米(p<0.01);薏米淀粉颗粒的粒径小于糯米淀粉;薏米淀粉的初始糊化温度和热焓值分别是糯米淀粉的1.08倍和2.04倍;薏米淀粉的结晶度是糯米淀粉的1.14倍;薏米支链淀粉FRI和FRIII分别比糯米降低了67.48%和11.87%。薏米难糊化的原因是由低淀粉含量和水分含量、高蛋白质含量、高淀粉热焓值和初始糊化温度、高淀粉结晶度、低支链淀粉FRIII含量等原因综合引起的,薏米淀粉的颗粒大小不是影响其难以糊化的因素。     

苦荞多酚对苦荞淀粉和小麦淀粉理化性质的影响

以苦荞淀粉和小麦淀粉为原料,研究低添加量(1%~4%)苦荞多酚与两种淀粉共糊化后的相互作用以及对其透明度、凝沉性、糊化特性、质构特性、抗性淀粉含量和微观结构的影响。结果表明:苦荞多酚与两种淀粉的共糊化显著降低了淀粉糊的透明度和沉降体积比,淀粉糊的凝沉加快;两种淀粉的糊化温度和糊化焓值一定程度上有所下降,淀粉更易糊化;同时两种淀粉胶质构参数显著降低,苦荞多酚添加量为4%时苦荞淀粉和小麦淀粉硬度分别下降了19.74%和54.18%;苦荞多酚的存在显著提高了淀粉中抗性淀粉含量(15%~30%)。电子显微镜结果显示,共糊化后苦荞多酚促进了淀粉颗粒的交联和聚合。苦荞多酚对淀粉理化性质的改变可视为一种提高抗性淀粉含量的物理改性方式,苦荞粉可作为高抗性淀粉食品的优质原料。     

水分对淀粉糊化度及鲜湿米粉品质的影响

探究了加水量对淀粉糊化度及鲜湿米粉理化品质、色泽、质构及机械性能的影响。结果表明:水分含量对大米淀粉的糊化程度及米粉品质影响显著;当加水量过低(65%)时,米粉糊化不均匀,形成的淀粉凝胶品质较差,米粉断条率高;当加水量过高(75%)时,形成的粉条易黏连,机械性能较差;加水量在65%~75%范围内,淀粉糊化均匀,制成的鲜湿米粉综合品质较好。     

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.     

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