卤蝇蛆壳甲壳素的提取及壳聚糖的制备工艺

对利用盐场废弃物卤蝇蛆壳提取甲壳素和制备壳聚糖的方法及工艺进行初步探索。确定最佳的工艺条件为 :蝇蛆壳∶盐酸 ( 2mol/L) =1g∶5mL ,在室温下反应 1h即可除去无机盐 ;另在室温下 ,先用质量分数 2 %NaOH与样品反应 4h后 ,过滤 ,再用质量分数 10 %NaOH于沸水中与样品反应 4h ,可有效去除蛆壳中的蛋白 ;脱乙酰基采用质量分数为 4 5 %的NaOH ,10 0℃ ,反应时间为 1h。在该条件下可得脱乙酰率较高的壳聚糖 ,制成的壳聚糖成品为白色 ,脱乙酰度为 78 90 % ,粘度为 1 12Pa·s。     

交变磁场对苹果多酚氧化酶反应动力学的影响研究

以邻苯二酚为底物,研究了交变磁场对苹果多酚氧化酶(PPO)反应动力学的影响。结果表明：苹果PPO褐变反应动力学符合米氏方程所描述的单底物酶促反应动力学。相应的动力学参数为Km=0.000687mol/L,Vmax=0.0477U/min。磁场强度小于0.87A/m 时,磁场处理的反应体系表现为促进作用。磁场强度为1.67A/m、处理时间小于3h 时,磁场处理表现为促进作用,处理时间大于3h 时,表现为抑制作用。磁场强度大于1.67A/m 时,磁场处理对反应体系都有抑制作用,而且随着磁场强度的增大,抑制作用增强。同一强度磁场在处理时间大于1h,随处理时间的增加,磁场处理的效果趋于平稳。以强度为4.22A/m 的磁场对多酚氧化酶反应体系的作用在出现促进作用后趋于稳定的抑制作用,0.5h 左右时促进作用最强,0.5h 之后开始呈现抑制作用,1h 左右抑制作用趋于平稳。以强度为4.22A/m 的磁场处理1h,其动力学参数Km 和 Vmax 分别变为0.0108mol/L 和0.0146U/min。表明交变磁场可抑制酶对底物的亲和力,并可使最大反应速度降低。     

蝇蛆壳制备壳聚糖的工艺条件研究

本试验探索了蝇蛆壳制备壳聚糖的最佳工艺条件。以蝇蛆壳中甲壳素为原料,采用碱液法制备壳聚糖。通过单因素试验考察了碱液浓度、液料比、反应时间对壳聚糖脱乙酰度的影响;根据Box-Benhnken中心组合试验设计原理,采用三因素三水平响应面分析法优化脱乙酰基反应条件,依据回归分析确定工艺条件的主要影响因素,以壳聚糖脱乙酰度为响应值作响应面和等值线图。通过分析各个因素的显著性和交互作用,得出脱乙酰基反应的最佳工艺条件为:液料比57.49:1(V/m),碱液浓度50%,反应时间7.3 h。在此条件下所得壳聚糖的脱乙酰度理论值为83.18%,实测值为79.45%,并得到白色粉末状壳聚糖。     

交联酯化木薯淀粉制备条件的研究

研究木薯淀粉经三偏磷酸钠交联和琥珀酸酐酯化修饰处理后热糊黏度特性的变化.指出交联剂用量、交联时间、交联pH值、酯化剂用量、酯化时间、酯化pH值和反应温度对结果的影响,并得出获得高黏度淀粉的最佳试验条件为:交联剂用量为0.02%;交联时间为3.3 h;交联反应pH值为9.7;酯化剂用量为2.4%;酯化时间为2.7 h;酯化反应pH为9.8;反应温度为34.8℃.     

家蝇幼虫耐高温抗氧化蛋白的筛选及其功能研究

为寻找耐高温抗氧化蛋白并探究其功能特性,采用60、80、100℃处理家蝇幼虫水提取液获得蝇蛆蛋白提取液。通过测定蝇蛆蛋白提取液中蛋白质含量、蛋白质组成以及体外抗氧化活性,确定获得蝇蛆耐高温抗氧化蛋白的最佳处理条件,并对所得蝇蛆耐高温抗氧化蛋白的疏水性以及其对H9c2细胞的氧化损伤保护作用及机理进行了分析。结果表明:高温处理家蝇幼虫水提取液可获得耐高温蛋白,并具有较理想的超氧阴离子自由基、羟自由基清除能力及较高的还原力,100℃处理20 min可获得耐高温抗氧化蛋白。该耐高温抗氧化蛋白可使H_2O_2诱导损伤的H9c2细胞存活率提高约39%,LDH渗出率降低约24%,有效增强细胞的SOD活力、CAT活力及GSH含量(P 0. 05)。研究显示,从蝇蛆中获得了具有良好耐高温特性的抗氧化蛋白,该蛋白对H_2O_2损伤的H9c2细胞有良好保护作用。     

蝇蛆几丁低聚糖抗烟草黑胫病研究

在室内进行了蝇蛆几丁低聚糖对烟草黑胫病菌(Phytophthora parasiticavar.nicotianae)的抑制效果和诱导抗性试验。试验结果表明:①蝇蛆几丁低聚糖对烟草黑胫病菌具有抑制作用,不同浓度的蝇蛆几丁低聚糖的抑制效果有差异,在一定范围内,随着几丁低聚糖浓度的提高,其抑制率也相应提高,1.0mg/mL的蝇蛆几丁低聚糖抑制效果显著,10d后抑制效果达到97.0%;②蝇蛆几丁低聚糖能够诱导接种烟叶对黑胫病产生抗性,浓度为1.0mg/mL的蝇蛆几丁低聚糖处理烟叶,第6d其诱抗效果达82.9%。     

诱导的家蝇幼虫分泌物抑菌活性的研究

探讨了应用液体饲料养殖蝇蛆和针刺诱导的蝇蛆分泌物的抑菌活性。蝇蛆用昆虫针针刺诱导,采用挤压蝇蛆生长时所需介质的方法即可得到诱导的蝇蛆分泌物,并用抑菌圈法测定该分泌物的抑菌活性。结果表明:利用含有一定量淀粉、蛋白质及其它微量营养素的液体饲料为营养源可成功地养殖蝇蛆。诱导的蝇蛆分泌物对大肠杆菌、金黄色葡萄球菌、藤黄八叠球菌及枯草芽孢杆菌的抑制作用均高于未诱导的蝇蛆分泌物,并且随着生长时间的推移,蝇蛆在化蛹之前其分泌物的抑菌活性有增强的趋势。     

酶解蝇蛆低聚几丁糖抗烟草黑胫病及对寄主同工酶的影响

对酶解蝇蛆低聚几丁糖抗烟草黑胫病茵(phytophthora nicotiana)及其作用机制进行了初步研究.结果表明,酶解蝇蛆低聚几丁糖对烟草黑胫病菌茵丝形态、产孢能力具有重要影响,引起茵丝生长扭曲、细小以及分支膨大,同时可抑制游动孢子囊的产生.烟苗经过酶解蝇蛆低聚几丁糖处理后,再接种烟草黑胫病菌,酶解蝇蛆低聚几丁糖能够诱导接种烟株对烟草黑胫病产生抗性,过氧化物酶(POD)、多酚氧化酶(PPO)同工酶活性增强,喷施酶解蝇蛆低聚几丁糖后接种病原茵的烟株,同工酶表现为酶带较多、色浓.由此可认为酶解蝇蛆低聚几丁糖抗烟草黑胫病与此两种同工酶有关.     

等离子体引发亚麻接枝丙烯酰胺的研究

采用空气等离子体引发亚麻接枝丙烯酰胺的方法改善其染色性能 ,以扫描电镜和红外谱图等手段验证了反应的发生 ,探讨了等离子体处理和接枝反应的工艺条件。即放电电压 10kV ,频率 40 0 0Hz ,接枝时间 2h ,温度 70℃ ,等离子体处理时间 40s ,接枝溶液浓度为 3 0 %。     

低温果浆酶处理对黑莓出汁率和几个理化指标的影响

用低温果浆酶处理黑莓浆液,探讨酶处理对黑莓出汁率、还原糖含量和色泽等的变化规律。在pH、酶作用时间、加酶量和反应温度单因素实验的基础上进行正交实验。结果表明,pH为3.5、低温果浆酶用量为0.2%,反应温度为30℃,作用时间为1.5h时,黑莓的出汁率最高。     

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