鸡血血红蛋白酶法提取血红素工艺优化

为了实现禽血高值转化利用,以鸡血血红蛋白为底物,采用蛋白酶酶解技术提取血红素。比较酸性蛋白酶、中性蛋白酶、碱性蛋白酶水解度确定合适的水解蛋白酶;研究并分析底物浓度、酶添加量、酶解时间对血红蛋白水解度、血红素得率、血红素纯度的影响;设计正交试验确定最优血红素提取工艺;采用最优酶解工艺参数酶解,经离心、冷冻干燥得到血红素产品,应用液相色谱-串联质谱（lipid chromatography-tandem mass spectrometry,LC-MS/MS）鉴定产品中血红素含量。结果表明,采用中性蛋白酶酶解,底物浓度4.0 g/100 mL、酶添加量2.0 g/100 mL、酶解时间4 h时,血红素得率、血红素纯度分别为52.23%、49.26%。血红素产品与血红素标准品保留时间相一致,血红素产品中血红素含量为50.24%。     

羊血亚铁血红素的酶法制备及抗氧化活性研究

以新鲜羊血为原料，通过酶水解法制备亚铁血红素，并测定其体外抗氧化活性。以水解度为评价指标，对比分析中性蛋白酶、木瓜蛋白酶、Alcalase2.4L碱性蛋白酶酶解效果，确定选用Alcalase2.4L碱性蛋白酶为水解酶。通过单因素实验及正交实验得到最优酶解工艺为：温度55℃、pH8.5、加酶量8000 U/g，酶解时间8 h。添加0.05%抗坏血酸抗氧化，最终血红素得率为94.65%，其中亚铁血红素纯度为83.87%。以Vc为阳性对照，通过测定亚铁血红素的DPPH自由基清除率、羟自由基清除率、ABTS自由基清除率研究其抗氧化活性，结果表明亚铁血红素有较好的抗氧化活性。     

分步酶解牛血红蛋白制备血红素多肽

为制备低苦味血红素多肽产物,以牛血红蛋白为原料,在木瓜蛋白酶、风味蛋白酶、中性蛋白酶、碱性蛋白酶的最适温度及p H下,通过L16(45)正交试验进行单酶酶解,筛选出分步酶解用酶,并采用L9(34)正交试验考察了分步酶解过程中底物质量分数、酶添加量比例、水解时间、水解时间比例等因素对水解度、苦味值、血红素含量等指标的影响。结果表明:分步酶解法酶解效果优于单酶酶解法;采用碱性蛋白酶和风味蛋白酶进行分步酶解,条件在底物质量分数6%,酶添加量比例5︰5,酶解时间10 h,酶解时间比例1︰1时可获得苦味值较低的富血红素多肽产物。     

复合酶水解猪血工艺条件优化研究

为了优化酶水解猪血制备血红素的工艺条件,对水解酶进行了选择研究,应用响应面分析法对水解条件进行优化.采用中性蛋白酶和木瓜蛋白酶复合水解,得出水解的最适工艺条件参数为:酶水解时间为123 min、酶水解温度为56℃、加酶比例(中性蛋白酶:木瓜蛋白酶)为0.98:1、酶用量0.11%.经测定水解液中血红素含量为4.40g/L.     

复合酶水解猪血红蛋白制备富血红素多肽

以木瓜蛋白酶和AS1398中性蛋白酶组成的复合酶对猪血红蛋白进行水解,制备富血红素多肽,考察底物质量分数、加酶比例、水解pH值和水解温度等因素对水解率、蛋白质回收率、血红素含量等指标的影响。结果表明：底物质量分数是影响水解率和蛋白质回收率指标的最重要因素;pH值是影响血红素含量指标的最重要因素;复合酶水解猪血红蛋白制备富血红素多肽的最佳工艺条件为底物质量分数6%、pH8、水解温度55℃、加酶比例5:5(木瓜蛋白酶:中性蛋白酶)。在此工艺条件下,猪血红蛋白水解产物具有较高的蛋白质回收率和血红素含量。     

酶解鹅血制备高氨基酸血红素

利用Box-Behnken中心组合实验设计对碱性蛋白酶水解鹅血提取高氨基酸鹅血血红素的工艺条件进行了优化。结果表明:对水解度的影响次序为酶浓度>水解温度>水解时间>溶液p H。鹅血提取高氨基酸血红素的最佳酶解工艺参数:酶浓度5%,温度50℃,p H8.80,水解时间5.15 h,水解度为14.36%±0.18%。水解后,水解液中血红素含量为1.210 mg/m L,铁离子的含量为90.42μg/m L。      

富血红素多肽产物制备用酶的比较研究

为筛选适于生产富血红素多肽产物的蛋白酶,比较不同蛋白酶对猪血红蛋白的水解效果。在AS1398 中性蛋白酶、2709 碱性蛋白酶、木瓜蛋白酶和胰蛋白酶的最适水解pH 值及温度下,以L16(45)正交试验研究酶种类、酶质量分数、底物质量分数和水解时间等因素对水解率、水解液中粗多肽含量和血红素含量等指标的影响。结果表明：酶种类和水解时间两因素对水解率指标的影响达到极显著水平(P ＜ 0.01);底物质量分数是影响粗多肽含量指标的最重要因素;酶种类对血红素含量指标的影响则达到显著性水平(P ＜ 0.05)。中性蛋白酶有利于提高水解率,木瓜蛋白酶有利于提高水解物的粗多肽含量,而碱性蛋白酶则有利于提高水解物的血红素含量。     

有限酶解猪血红蛋白制备亚硝基血红素多肽的研究

为了使亚硝基(NO-)更易结合于血红素亚铁离子及提高色素稳定性,本研究采用蛋白酶有限酶解猪血红蛋白,酶解液中大分子血红素多肽与亚硝基反应合成亚硝基血红素多肽。试验表明,以选用木瓜蛋白酶效果较好,最佳酶解条件为:底物浓度16%,加酶量4000U/g,水解时间6h;酶解液合成色素最佳参数为:pH5.00,反应时间12min,反应温度为55℃,NaNO2的添加量为1.6%。     

酶法水解梅鱼蛋白的实验研究

主要研究了碱性蛋白酶、风味蛋白酶、复合蛋白酶、中性蛋白酶对小梅鱼的水解作用。采用正交试验,详细比较了温度、酶浓度、水解时间、酶比例对鱼蛋白水解度的影响。结果表明:单酶最佳水解酶为碱性蛋白酶,其水解条件:温度60℃,加酶量0.3%(以蛋白含量计),时间5h,水解度达51.02%;碱性蛋白酶与复合蛋白酶双酶的最佳水解条件:碱性蛋白酶与复合蛋白酶比例为3∶1,温度为60℃,加酶量0.3%,时间5h,水解度达57.03%;碱性蛋白酶、复合蛋白酶与风味蛋白酶三酶的最佳水解条件:碱性蛋白酶与复合蛋白酶比例为3∶1,温度60℃,加酶量0.3%,反应5h后添加风味蛋白酶,其反应条件:加酶量0.3%,温度60℃,时间为6h,水解度达62.57%。     

响应面法优化鸡胸肉蛋白酶解工艺

应用单因素试验和响应面分析法对复配蛋白酶的种类和复配蛋白酶水解鸡胸肉蛋白的工艺条件进行优化,选择复配蛋白酶比例（复合蛋白酶∶木瓜蛋白酶）、复配蛋白酶添加量、复配蛋白酶水解温度以及固液比4 个因素,以鸡胸肉蛋白的水解度为评价指标,通过4因素3水平的Box-Behnken响应面分析法优化水解条件。结果表明：选择复合蛋白酶和木瓜蛋白酶进行复配,复合蛋白酶与木瓜蛋白酶复配比例3.24∶1、复配蛋白酶添加量2.16%、水解温度51.29 ℃、固液比1∶4.20。通过此工艺条件制得的鸡胸肉蛋白酶解液的水解度达到32.84%,验证实验水解度为（32.71±0.51）%,说明试验结果与软件优化结果相符,且制得的酶解液营养丰富,感观性状好,风味佳。     

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