α-淀粉酶对辛烯基琥珀酸酐水解玉米淀粉影响

以玉米淀粉为原料,研究α-淀粉酶对辛烯基琥珀酸酐水解淀粉影响。通过水解单因素实验,结果显示,辛烯基琥珀酸酐淀粉水解反应随水解温度升高,淀粉酶量可提高淀粉水解程度,反应时间延长(从30 min到60 min较为明显)水解DE值逐渐升高。通过水解响应面分析实验,结果显示,加酶量与水解温度、水解温度与水解时间之间交互影响作用...     

酶解辛烯基琥珀酸酐淀粉DSC、IR、黏均分子量研究

在单因素实验和响应面分析实验的基础上对制备的酶解辛烯基琥珀酸酐玉米淀粉的DSC特性、IR特性及黏均分子量进行了分析研究。结果显示:利用DSC扫描辛烯基琥珀酸酐淀粉和酶解辛烯基琥珀酸酐淀粉,发现二者的To、Tp、Tc较原淀粉都降低。玉米原淀粉经辛烯基琥珀酸酐酯化后引入了OSA基团,而辛烯基琥珀酸酐淀粉经α-淀粉酶水解后,并没有影响分子中的OSA基团,只是淀粉分子链缩短,分子量降低。通过黏均分子量的测定,表明经过α-淀粉酶的水解确实将淀粉分子链缩短,分子量降低。     

辛烯基琥珀酸淀粉酯的制备及其酶法降解的研究

以蜡质玉米淀粉为原料,辛烯基琥珀酸酐为亲核试剂,用正交试验方法确定了在不同条件下,制备辛烯基琥珀酸淀粉酯的最佳工艺参数,着重研究了酯化反应条件对反应取代度的影响。实验结果表明:在辛烯基琥珀酸酐添加量(淀粉干基重的3%)不变的条件下,淀粉乳的浓度、反应温度、反应体系pH值、反应时间对反应取代度均有较大影响。对制备的淀粉酯中的辛烯基琥珀酸酐残留量进行了测定,结果表明,利用本文确定的最佳反应条件制得的淀粉酯辛烯基琥珀酸残留量低于规定标准。利用α-淀粉酶对制得的淀粉酯进行了降解处理,探讨了利用不同的酶解时间,获得不同DE值样品的酶解条件。利用最佳工艺条件,进行了辛烯基琥珀酸淀粉酯的中试放大并获得了预期产品。     

低粘度辛烯基琥珀酸淀粉酯的酸水解条件研究

水解时间、温度、酸浓度是影响辛烯基琥珀酸淀粉酯酸水解过程的主要因素。文中通过中心组合实验设计及响应面分析建立了辛烯基琥珀酸淀粉酯的水解模型,求出了酸法制备低粘度辛烯基琥珀酸淀粉酯(DS0.156,粘度0.004 Pa.s,12 r/min)的最佳工艺条件:时间6.39 h,温度49.85℃,酸浓度1.48%     

辛烯基琥珀酸酐酶解淀粉在冷食品中应用初探

以玉米淀粉为原料进行辛烯基琥珀酸酐酯化,再以α-淀粉酶水解成不同程度的辛烯基琥珀酸酐酶解淀粉.通过对制备的辛烯基琥珀酸酐酶解淀粉的乳化能力、乳化稳定性的测定,探究出该复合改性淀粉的乳化性能,结果显示复合改性淀粉的乳化性能与原淀粉相比有较大的提高;通过亲水亲油平衡值( HLB值)的测定,结果显示不同取代度(DS)的辛烯基琥珀酸酐酶解淀粉的HLB值均大于10,可以作为乳化剂应用到水包油的乳化体系中.通过比较辛烯基琥珀酸酐酶解淀粉和其他商业乳化剂产品在冷食品(雪糕)中的乳化效果,结果显示辛烯基琥珀酸酐酶解淀粉作为乳化剂制备的雪糕膨胀率最高可以达到144％,感官评分可以达到20分,是一种比较理想的冷食品(雪糕)乳化剂.     

响应面制备辛烯基琥珀酸淀粉酯的工艺研究

通过响虚面分析(Response surface analysis,RSA)软件,采用boxbehnken中心组合设计方法对辛烯基琥珀酸淀粉酯(SSOS)的制备工艺条件进行优化,得到制备辛烯基琥珀酸淀粉酯的最佳工艺条件为:反应温度为34℃,时间1.5h,pH值为8.7,辛烯基琥珀酸酐添加量为淀粉干基的3%,反应取代度(DS)可达0.0144.     

蜡质玉米辛烯基琥珀酸麦芽糊精酯的制备及性能研究

采用蜡质玉米淀粉为原料,辛烯基琥珀酸酐(OSA)为酯化剂,应用湿法工艺制备了辛烯基琥珀酸淀粉钠(SSOS)。使用耐高温α-淀粉酶对SSOS进行酶解处理,制备了蜡质玉米辛烯基琥珀酸麦芽糊精酯(MSSOS)。研究了OSA用量对SSOS取代度(DS)的影响;探讨了耐高温α-淀粉酶用量、酶解时间、淀粉乳浓度、酯化程度对MSSOS产品葡萄糖值(DE)的影响;并对具有不同DE值MSSOS在表观黏度、透明度、乳化稳定性等性能的差异进行了比较分析。结果显示:(1)SSOS的DS值随OSA用量的增加呈升高趋势;(2)随DS值的升高,SSOS的HLB值增大,亲水性加强、淀粉的糊化温度降低、峰值黏度升高;(3)MSSOS的DE值随α-淀粉酶用量的增加和酶解时间的延长而升高,SSOS的酯化程度对DE值影响不大;(4)随DE值的升高,MSSOS表观黏度降低,透明度增大;DE值高于11.5%后,乳化稳定性降低。     

大米辛烯基琥珀酸酯淀粉中取代基团的分布

以大米原淀粉为原料,采用湿法工艺制备辛烯基琥珀酸淀粉酯(OSA-starch)。以浓度2.0 mol/L HCl处理不同时间,得到不同酸水解程度的辛烯基琥珀酸淀粉酯。采用扫描电子显微镜、X-射线衍射分析、X射线光电子能谱分析(XPS)等方法研究辛烯基琥珀酸酐(OSA)取代基团在大米淀粉分子中的分布情况。结果表明,随着酸水解时间延长,OSA淀粉取代度降低,黏度显著下降。与原淀粉相比,OSA淀粉及酸水解OSA淀粉的表面均出现凹陷现象,而颗粒结构与晶型结构均未发生改变,结晶度增加。XPS结果表明辛烯基琥珀酸酐变性大米淀粉的表面分布大量的辛烯基琥珀酸基团。辛烯基琥珀酸酐(OSA)基团与淀粉分子的作用主要发生在淀粉颗粒表面和淀粉分子的非结晶区域,且较少破坏淀粉的内部结构。     

辛烯基琥珀酸芋艿淀粉酯制备及性质研究

以芋艿淀粉为原料,采用湿法制备辛烯基琥珀酸芋艿淀粉酯。以辛烯基琥珀酸淀粉酯取代度(DS)为指标,研究芋艿淀粉浓度、辛烯基琥珀酸酐用量、反应温度、反应时间对辛烯基琥珀酸芋艿淀粉酯制备的影响。在单因素试验的基础上,通过正交试验优化辛烯基琥珀酸淀粉酯制备工艺。结果表明:辛烯基琥珀酸芋艿淀粉酯制备的适宜工艺条件:淀粉质量分数40%、辛烯基琥珀酸酐用量为2.0%芋艿淀粉干重、反应温度40℃、反应时间3 h。在该工艺条件下,制得的辛烯基琥珀酸芋艿淀粉酯颗粒结构发生变化,糊化温度由原淀粉的最高温度85.49℃变为82.15℃,红外光谱图中1 710~1 740 cm-1,1 550~1 610 cm-1区间分别出现酯羰基(C=O)伸缩振动吸收和RCOO-特征吸收,可断定辛烯基琥珀酸与淀粉酯化生成辛烯基琥珀酸淀粉酯。     

玉米木薯辛烯基琥珀酸淀粉钠的生产工艺研究

研究了玉米与木薯比例、辛烯基琥珀酸酐(OSA)的添加量,反应温度、pH值对玉米木薯辛烯基琥珀酸淀粉钠黏度的影响,并确定了玉米木薯混合原料辛烯基琥珀酸淀粉钠的酯化生产工艺,结果表明:随着玉米淀粉与木薯淀粉比列的增加,辛烯基琥珀酸淀粉钠的糊化温度逐渐降低;玉米淀粉与木薯淀粉比例1:4,反应温度25℃条件下,pH维持在8.5,加入辛烯基琥珀酸酐(OSA)量为2%时,制备得到的玉米木薯辛烯基琥珀酸淀粉钠黏度最高。     

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