紫甘蓝花色苷色素稳定性研究

以大孔吸附树脂分离纯化,冻干所得紫甘蓝色素粉末为原料,研究pH、温度、抗坏血酸、金属离子及寡糖等因素对紫甘蓝花色苷稳定性影响。结果表明,pH对紫甘蓝花色苷稳定性影响较大,花色苷含量随pH增大而下降,且当pH>7时,花色苷稳定性呈极显著降低趋势;紫甘蓝花色苷热稳定性较好,但温度>80℃时,紫甘蓝花色苷热稳定性较差;金属离子影响存在差异,Na~+、K~+对花色苷稳定性无显著性影响,Ca~(2+)对其稳定性影响显著,而Zn~(2+)、Al~(3+)影响达到极显著程度;高浓度抗坏血酸影响紫甘蓝花色苷稳定性;蔗糖对紫甘蓝花色苷表现为辅色作用,葡萄糖、乳糖、果糖等寡糖对紫甘蓝花色苷稳定性影响较小。     

黑花生衣花色苷含量测定及稳定性研究

从黑花生衣中提取花色苷,并测定其含量;测定不同温度、酸碱度、光照及金属离子(Cu2+、Mn2+、Mg2+、Fe3+)对黑花生衣花色苷稳定性的影响。在提取条件为料液比1∶50、乙醇浓度60%且为酸性、温度60℃、提取时间60min时,黑花生衣色素中花色苷含量为10.3mg/g;加热对花色苷有增色作用;pH小于5.0时随着pH增大花色苷的吸光度降低,pH大于5.0时随pH增大花色苷的吸光度增加,并朝蓝色趋势渐变;pH越接近7.0,光照后花色苷保存率越高;在Mn2+、Mg2+浓度为2.00mmol/L时,花色苷吸光度最高;随Fe3+、Cu2+浓度增加花色苷的吸光度随之增加,铁离子对黑花生衣花色苷无絮凝作用。     

紫甘蓝花色苷稳定性及热降解动力学研究

为有效控制紫甘蓝加工过程中花色苷的降解,研究了pH、温度、光照、金属离子及外源添加物对花色苷稳定性的影响。实验表明,紫甘蓝花色苷稳定性受pH、温度和光照影响较大,pH2.0左右的花色苷5 h保存率仍有92.92%±0.69%、40℃下避光5 h花色苷保存率有70.50%±0.52%,花色苷稳定性较强;添加不同浓度的金属离子（K+、Mg2+、Na+）低浓度Fe3+（0.01~0.02 g/mL）及抗坏血酸（0.03 g/mL）、蔗糖和乳糖均可提高花色苷稳定性;氧化剂H₂O₂及还原剂Na₂SO₃、高浓度Fe3＋（0.03~0.04 g/mL）和抗坏血酸（0.09和0.12 g/mL）均加快花色苷降解,且降解速率随浓度增大而增加。花色苷热降解符合一级动力学,降解速率随温度升高而增加,半衰期随之减小,50℃ pH2.0的t_1/2最大为67.28 h,活化能最大为39.16 kJ/mol,为吸热非自发反应。采用紫甘蓝花色苷加工产品时,应尽量使温度低于40℃或者控制pH在2.0左右、选择提升或者不影响花色苷稳定性的辅料,于避光环境下操作及储存。     

响应面法优化紫甘蓝中花色苷提取工艺及抗氧化性研究

以紫甘蓝为研究对象,以花色苷提取率为考察目标,利用响应面分析法对紫甘蓝中花色苷的提取工艺进行优化并测定花色苷的抗氧化能力。在单因素试验的基础上,采用响应面分析法中的Box-Behnken模式进行三因素三水平的试验设计。结果表明:乙醇体积分数40%、温度41℃、料液比1∶36(g/mL)时,紫甘蓝花色苷提取率最高。在此试验条件下花色苷含量为13.92 mg/g。抗氧化活性试验表明:紫甘蓝花色苷提取物还原能力较强,能较好的清除DPPH自由基和ABTS+自由基,当花色苷浓度为150 mg/mL时,清除ABTS+自由基能力达到97%,表明所提取紫甘蓝花色苷具有较强抗氧化性。     

高速逆流色谱分离纯化紫甘蓝花色苷

优化出超声波溶剂辅助法提取紫甘蓝花色苷的最佳工艺条件,并用高速逆流色谱法对其进行分离纯化,建立HSC-CC分离制备紫甘蓝花色苷类化合物的方法。采用正交试验优化超声波溶剂辅助提取紫甘蓝花色苷的工艺条件,再高速逆流色谱对其进行分离纯化。结果表明,超声波溶剂辅助提取紫甘蓝花色苷的最佳工艺条件为超声时间8min,超声辅助提取温度40℃,乙醇体积分数65%;HSCCC制备紫甘蓝花色苷类化合物的方法:溶剂系统为正丁醇-甲基叔丁基醚-乙腈-水-三氟乙酸(2:2:1:5:0.01,V/V/V/V),流速为2mL/min,主机转速设定为800r/min,紫外检测波长为254nm,在该条件下分离制备得到3种化合物。经HPLC检测其纯度分别为76.28%,45.46%,91.46%。用超声波溶剂辅助和高速逆流色谱能分离得到了高纯度的紫甘蓝花色苷,该法具有简便、快速的优点,为紫甘蓝花色苷的分离纯化提供了高效、稳定、可靠的方法。     

树莓花色苷稳定性的研究

以红树莓花色苷为研究对象,系统研究了光照、温度、pH、食品添加剂和金属离子对树莓花色苷稳定性的影响。结果表明,随加热温度的升高花色苷稳定性下降,在60℃以下花色苷稳定;室外自然光照花色苷不稳定,避光条件下稳定性良好;在pH1.0和pH3.0时花色苷稳定,pH5.0、7.0、9.0花色苷不稳定。食品添加剂苯甲酸钠和蔗糖使花色苷稳定性增加,抗坏血酸使花色苷稳定性降低。金属Al3+离子对花色苷具有增色效应,Al3+和Ca2+对花色苷稳定性无影响。     

黑粒小麦麸皮中花色苷的提取及性质研究

为了对我校自主培育的黑粒小麦麸皮中花色苷进行开发利用,本试验以黑粒小麦麸皮为原料,进行了花色苷的提取条件和理化性质的研究。结果表明,用pH 1.0、40%的乙醇作提取剂,在料液比为1∶20(g/mL)、70℃条件下浸提80 min,提取效果最好,花色苷得率为14.5%;该花色苷可见光范围内的最大吸收波长为525 nm,pH对其影响明显,温度影响不大,60℃以内比较稳定。Mg2+、K+和Al3+对该花色苷有很好的增色、稳定作用,Ca2+和Fe2+对其稳定作用影响不大,Cu2+、Zn2+和Fe3+使其明显褪色。该花色苷耐氧化性、耐还原性差,耐光性好。蔗糖、柠檬酸对其有明显的褪色作用,苯甲酸钠在低质量浓度(<0.1 mg/mL)时对其基本无影响,在高质量浓度(>0.2 mg/mL)时有一定的褪色作用,盐对其有一定的增色、稳定作用。     

桑葚花色苷的提取纯化及稳定性

采用超声辅助溶剂法提取桑葚花色苷,以吸附率和解吸率为指标,从大孔树脂HPD600、D101、LX1180、AB-8、DA201-C中筛选出性能较优的树脂对其进行纯化,最后对纯化后花色苷的稳定性进行研究。结果表明:以40%乙醇溶液(含0.1% HCl)为提取剂,料液比1:10,超声时间90 min,花色苷得率为2.9 mg/g。HPD600是纯化花色苷较为理想的树脂,除糖率67.6%,纯化后样品总花色苷含量为16.7%,色价为46.1,产品为紫黑色粉末,经高效液相色谱检测其含有约41.2%的矢车菊素-3-O-葡萄糖苷。随着温度、pH、光照强度的上升,花色苷的稳定性降低。Na+、Mg2+、Al3+对花色苷的稳定性影响不大,Cu+、Cu2+、Fe2+、Fe3+对花色苷有一定的破坏作用。因此,应在25℃、低pH、避光条件下对桑葚花色苷进行加工与保存,同时避免接触铜离子和铁离子。     

蛇莓果实花色苷的稳定性及其降解动力学

探究蛇莓果实花色苷在多种条件下的稳定性及降解动力学。采用pH示差法测定不同pH值、温度、光照强度、氧化剂、还原剂、金属离子对花色苷稳定性的影响。研究表明,不同pH条件下蛇莓果实花色苷热降解符合一级动力学模型,花色苷在强酸性条件下的稳定性高于弱酸和中性条件;蛇莓果实花色苷的热稳定性较差,随着环境温度升高,降解速率k增大,半衰期和递减时间D值缩短,pH值2.0时活化能最大为68.65 kJ/mol,pH值5.0时活化能最小为42.35 kJ/mol,其降解为吸热非自发反应;6 000 lx光照和H2O2均会加快蛇莓果实花色苷的降解,且花色苷在光照和H2O2条件下降解均符合一级动力学模型,在光照条件下的降解速率为 0.012 3 d-1,半衰期56.35 d,H2O2条件下降解速率随H2O2体积分数的升高而增大;质量分数0.20%的Na2SO3对蛇莓果实花色苷的降解有抑制作用;Na+、K+对蛇莓果实花色苷无影响,而Al3+、Cu2+、Fe3+可显著破坏蛇莓果实花色苷的稳定性。综上,蛇莓果实花色苷应尽量在酸性、低温、避光且无氧化剂及Fe3+的条件下生产加工,以避免大量降解。     

食用玫瑰花色苷的提取及其稳定性研究

以吸光值为指标得出了食用玫瑰花花色苷提取的最佳条件:10%的柠檬酸溶液为浸提液,料液比1:10,50℃提取1.5h。对花色苷粗提物的稳定性研究表明,玫瑰花色苷对溶液pH敏感,随着pH的升高,最大吸收波长红移,颜色由红色逐渐变为灰色;热稳定性较好;光照、Mg2+、VC、氧化剂及还原剂能够破坏花色苷的结构,使其降解;Cu2+、Al3+、Ca2+、Na+及蔗糖可能与色素发生辅色效应从而明显地提高了其稳定性;K+、Zn2+、Fe2+及葡萄糖则没有显著的影响。     

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