不同老化工艺对甘薯回生抗性淀粉制备率的影响

以甘薯淀粉为原材料,甘薯淀粉回生率为指标,研究冷藏、常温、真空减压和干燥箱干燥等不同老化工艺对甘薯回生抗性淀粉生成率的影响.结果表明,4℃冷藏条件下,老化72 h后甘薯淀粉回生率达到最高,由9.2％提高到13.4％;常温下,大气温度为16～19℃,大气湿度为68％～80％时,常温老化96 h后甘薯淀粉回生率达到最高,由9.9％提高到15.4％;真空干燥箱温度为30℃,真空度为0.08 MPa时98 h甘薯淀粉回生率最大为20.96％;干燥箱温度为30℃时,老化90 h甘薯淀粉回生率最大为15.38％;真空老化有利于甘薯淀粉回生.     

葛根抗性淀粉的制备工艺研究

本文以葛根淀粉为原料,采用加入普鲁兰酶的作用,对淀粉增抗的影响因素及工艺进行了研究,采用单因素实验和L9(34)正交实验,研究了淀粉乳浓度、冷藏温度、冷藏时间、回生次数对抗性淀粉(Resistant Starch,RS)含量百分率的影响.结果表明:回生次数是影响RS含量的主要因素;最佳增抗工艺参数:淀粉乳浓度9%、冷藏温度4℃、冷藏时间27h、回生次数3次.     

酵母菌发酵生淀粉提高马铃薯淀粉回生率机理研究

以马铃薯淀粉为原料,淀粉回生率为考察指标,研究酵母菌发酵对马铃薯淀粉回生率的影响。通过对比发酵前后马铃薯回生淀粉的可见和红外吸收曲线,分析了酵母菌发酵提高马铃薯淀粉回生率的机理。结果表明,纤细酵母菌发酵马铃薯淀粉可使马铃薯淀粉回生率由12%提高到39.4%,提高了2.28倍。发酵后马铃薯回生淀粉中直链淀粉的最大可见吸收波长为587.8 nm,大于发酵前的569.6 nm。酵母菌发酵马铃薯淀粉提高其回生率的原因有两方面:一是发酵过程产生的酶使马铃薯支链淀粉脱支生成直链淀粉,增加了参与回生直链淀粉的量;二是发酵过程使马铃薯淀粉中醛基部分转变为伯醇基,进而生成糖苷键,增加直链淀粉链长,有利于淀粉回生过程晶体长大。     

红小豆和红花豆淀粉热性质及回生性质的比较

以红小豆和红花豆为研究对象,分析比较了两种淀粉的化学组成、颗粒形状、结晶性质、热性质及回生性质。SEM结果表明,大颗粒红小豆和红花豆淀粉大颗粒成肾状或卵形,小淀粉颗粒成球形;XRD试验结果表明,红小豆和红花豆淀粉结晶类型为A型,结晶衍射峰2θ角均在15.0°,17.0°,19.0°和22.8°左右;DSC扫描结果表明,红小豆和红花豆淀粉的熔点温度分别为62.12℃±0.29℃和62.17℃±0.22℃,峰值温度分别为68.87℃±0.22℃和68.76℃±0.31℃,糊化焓变值分别为11.73±0.62 J/g和14.63 J/g。回生试验结果表明,红小豆和红花豆淀粉凝胶在4℃贮藏期间,回生淀粉熔点和峰值随时间延长而下降,回生焓变随时间延长而增长,红小豆和红花豆淀粉凝胶在7 d时重结晶过程基本结束,且与直链淀粉含量相关。因此,在工业应用中可以通过测定淀粉热性质来预测其用途,也可通过控制淀粉基食品中直链淀粉比例加速或抑制淀粉基食品老化过程,进而提高淀粉基食品的食用价值。     

超高压作用对酸解玉米淀粉回生性能的影响

25℃条件下,30%的玉米淀粉悬浮液(w/v)经2.0mol/L盐酸溶液温和酸解8h,得到酸解玉米淀粉.将酸解后的玉米淀粉配制成5%的淀粉悬浮液(w/v),分别在300、400、500、550MPa压力下处理5min,然后在-4℃下分别静置回生0、1、2、3d、4d后进行干燥处理.利用x-射线衍射仪对样品的结晶度进行测定,结果表明:经冷藏回生后.回生1d以上的样品的结晶度有所提高,300MPa放置回生3d的样品回生程度最大,500MPa回生4d的样品回生程度也较高,550MPa高压作用后酸解淀粉的回生程度不明显.     

干燥工艺对甘薯淀粉回生率影响

以甘薯淀粉为原材料,以甘薯淀粉回生率为指标,研究常温、太阳晒、真空减压、干燥箱和微波干燥等不同干燥工艺对甘薯回生抗性淀粉生成率影响。结果表明,各干燥最佳工艺参数为:常温下大气温度为16℃～19℃、大气湿度为68%～80%时,老化后甘薯淀粉5 d达至恒重,回生率由3.5%提高到4.5%,提高28.5%;阳光照射下,大气温度为23℃～36℃、大气湿度为42%～74%时,老化后甘薯淀粉5 d达至恒重,回生率由3.5%提高到4.7%,提高34.2%;真空干燥箱温度为120℃、真空度为0.08 MPa时,甘薯淀粉回生率最大,为14.62%,比空白提高3.1倍;干燥箱温度为90℃时,甘薯淀粉回生率最大,为12.24%,比空白提高2.5倍;微波温度为45℃时,甘薯淀粉回生率最大,为7.12%,比空白提高1倍;相比之下,真空干燥有利于甘薯淀粉回生。     

普鲁兰酶和α-淀粉酶法制备缓慢消化淀粉的比较研究

以普通玉米淀粉为原料,分别应用普鲁兰酶和α-淀粉酶制备缓慢消化淀粉（SDS）,并优化SDS制备工艺。通过正交试验确定普鲁兰酶法制备SDS的最佳条件为：酶用量为160U,酶解时间为8h,冷藏回生时间为3d,淀粉乳浓度为10%。在上述条件下,SDS的质量浓度最高,为21.77%;同样通过正交试验确定α-淀粉酶法制备SDS的最佳条件为：酶用量为200U,酶解时间为25min,冷藏回生时间为3d,淀粉乳浓度为10%。在上述条件下,SDS的质量浓度最高,达到20.27%。由于两种方法制备得到的SDS质量浓度差别不大,但α-淀粉酶价格较低,酶解时间短,因此其生产成本相对较低,所以选择α-淀粉酶制备SDS。     

UHT灭菌乳在贮藏期内的品质变化

选择了市售塑料袋装UHT灭菌乳(保质期为30 d),研究了其在4℃冷藏避光、4℃冷藏光照、25℃室温避光、25℃室温光照、37℃避光,37℃光照6种贮藏条件下,贮藏期内主要理化指标和微生物指标的变化.结果表明,在整个贮藏期内.UHT灭菌乳的酸度持续增加,10～15 d酸度增长幅度最大,37℃条件下,最大酸度可达到22.14°T;在6种贮藏条件下蛋白质量分数均相对稳定;在贮藏的前10 d,试验样品细菌总数均小于1 mL-1,之后持续增长;光照与否,各取样点维生素C质量浓度差异显著.     

玉米、甘薯和马铃薯直链淀粉回生前后可见及红外吸收变化分析

为了探索淀粉中直链淀粉的单独回生性质,研究了玉米、甘薯和马铃薯直链淀粉回生前后的可见及红外吸收变化情况。实验结果表明,回生前直链淀粉可见最大吸收分别为玉米627.4nm、甘薯575.4 nm、马铃薯627.5 nm,回生后分别为玉米568.2 nm、甘薯569.6 nm、马铃薯569.6nm。红外结果表明,少量连接多肽的玉米直链淀粉参与了回生,这些淀粉再次回生时连接多肽和氨基酸的淀粉没有参与回生,3种淀粉中连接脂肪的淀粉未参与回生。水参与了淀粉回生晶体的形成,不同晶型可通过晶体中水的H-O-H弯曲振动判别。     

β-淀粉酶抑制面制品回生工艺优化的研究

以小麦粉为原料,通过β -淀粉酶对面制品进行抗回生处理,研究了加酶量、酶作用时间、酶作用温度对β -淀粉酶抑制面制品回生效果的影响,并在单因素试验基础上,采用响应面分析法对β -淀粉酶抑制面制品回生工艺进行优化,结果表明,β -淀粉酶抑制面制品回生工艺的最佳条件为:酶浓度为45.8 U,酶作用温度为57℃,酶作用时间32.2 min.在此工艺条件下制得的面制品,经4℃下冷藏48 h后测得的硬度为(3299.86±8.32)g,而未经β-淀粉酶抗回生处理的面制品,经4℃下冷藏48 h后测得的硬度为(12950±7.22)g.面制品硬度降低了74.52％.     

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