骆驼瘤胃乳酸菌的分离、鉴定及其降解吲哚的功能研究

为研究从驼骆瘤胃内容物分离、筛选的乳酸菌,其体外降解吲哚的功能。利用MRS培养基筛选骆驼瘤胃乳酸菌,提取细菌总DNA,扩增16S rDNA序列,构建系统发育树。在以吲哚(500 mg/L)为唯一碳源、氮源的无机盐培养基中胁迫培养乳酸菌,紫外分光光度计测定吸光度值(600 nm),测定乳酸菌在高浓度吲哚环境中的生长曲线;使用GC-MS动态检测吲哚残留量,测定乳酸菌对吲哚的降解能力。结果显示:筛选获得4株乳酸菌,GU366019、GU366027、GU366021、GU366034均归属为乳杆菌属(Lactobacillus),其中GU366019、GU366027、GU366021为德氏乳杆菌亚种(Lactobacillus delbrueckii subsp.),GU366034为驯马乳杆菌(Lactobacillus equicursoris)。四株菌在添加吲哚的无机盐培养基中生长缓慢,但对吲哚降解能力强。GU366027、GU366019、GU366021在144 h内,GU366034在156 h可将吲哚100%降解,证实来源于骆驼瘤胃的乳酸菌具有降解吲哚的功能。本实验在补充肠道毒素降解微生物资源的同时,也为乳酸菌降解、清除肠道毒素提供了研究依据。     

新疆自然发酵骆驼酸乳中乳酸菌降解胆固醇能力研究

以新疆骆驼酸奶分离出的10株初步鉴定为乳酸菌的菌株为研究对象,进行体外胆固醇降解能力的研究。用富集培养方法筛选出具有降解胆固醇能力的乳酸菌,然后将菌株接种到发酵培养基中进行发酵产酶,离心得酶液,用分光光度法测定其酶液对胆固醇的降解率,进而分析研究各菌株降解胆固醇的能力。有9株乳酸菌能够在以胆固醇为唯一碳源和能源的液体培养基中生长,其中3株菌对胆固醇降解率达到了60%。实验通过对自然发酵的骆驼酸乳中分离得到的乳酸菌的体外降解胆固醇的实验研究,表明骆驼酸乳中的乳酸菌具有一定的降解胆固醇的能力。     

川西高原发酵牦牛乳中降解亚硝酸盐乳酸菌的筛选与耐受性研究

以川西高原发酵牦牛乳中分离出的195株乳酸菌为研究对象,采用比色法测定其亚硝酸盐降解能力,从中筛选出亚硝酸盐降解能力极强的菌株。将这些优势菌株分别在人工胃液、人工肠液、胆盐和高盐4个模拟人工胃肠道消化环境中进行培养,测其耐受力。结果表明:这195株乳酸菌亚硝酸盐降解率范围为35.79%~96.51%,其中降解率在80%~90%的菌株占54.87%,仅有1.54%的菌株亚硝酸盐降解率在50%以下,有3株亚硝酸盐降解能力极强的菌株(降解率大于95%)。这3株菌在人工胃液中的活菌数随培养时间的延长而减少,培养3 h后,菌株5、26、150在pH5.5时的活菌数分别为3.7、3.6、4.1×10⁸ CFU/mL;在人工肠液中培养4 h后,菌株5、26、150的活菌数分别为4.3、6.8、5.3×10⁸ CFU/mL;在不同胆盐梯度的培养基中培养24 h后,3株菌的活菌数随胆盐浓度增大而减少,且均保持在10⁸ CFU/mL以上;在高盐环境中培养24 h后的活菌数随盐质量浓度的增加而降低,活菌数均在10⁸ CFU/mL以上。结论:川西高原发酵牦牛乳中分离出的195株乳酸菌降解亚硝酸盐的能力存在较大差异,其中降解亚硝酸盐能力极强的菌株对体外模拟消化环境具有较好的耐受力,为其在医药,食品和生物领域的应用提供了理论依据。     

青藏高原牦牛酸奶中降胆固醇乳酸菌的筛选及特性研究

目的:本研究旨在从天祝、那曲、若尔盖、玉树、红原和玛曲采集的202份牦牛酸奶样品中,筛选出具有高降胆固醇特性的优良菌株。方法:选择MRS、M17和SL培养基(MRS培养基是培养乳酸菌的基础培养基,M17培养基和SL培养基均为分离乳酸菌的培养基,其中SL培养基为分离嗜酸性乳酸菌的培养基)进行分离纯化,过氧化氢筛选阴性菌。根据邻苯二甲醛法测定胆固醇,筛选具有降解脂溶性胆固醇能力的菌株,水溶性胆固醇法复筛验证菌株降解能力,16SrDNA分子生物学法鉴定其种属。结果:分离纯化后总计720株乳酸菌,所有菌株经初筛都具有一定的胆固醇降解能力,其中降解率在68%以上的菌株,共有52株,菌株BX39的胆固醇降解率高达90.05%;复筛发现菌株BT18胆固醇降解率高达96.26%;16S rDNA分子生物学法分析比对后发现,72株乳酸菌中有64株罗伊氏乳杆菌、4株乳酸片球菌、3株瑞士乳杆菌和1株植物乳杆菌。结论:罗伊氏乳杆菌BT18具有高降胆固醇特性,可作为后备菌株进一步的研究和利用。     

湖南剁辣椒降解亚硝酸盐乳酸菌筛选鉴定及发酵特性研究

为筛选出湖南地区剁辣椒中具有高效降解亚硝酸盐的乳酸菌,从湖南省4个市采集的12个样品中共分离出33株乳酸菌。将分离出的乳酸菌在含有250 mg/L亚硝酸盐的MRS培养基中培养24 h,选取降解亚硝酸盐能力较强的乳酸菌,进行16S rDNA分子生物学鉴定,并测定其发酵特性。实验中选育了4株具有较强降解亚硝酸盐能力的乳酸菌,分别为短乳杆菌、德氏乳杆菌、植物乳杆菌以及戊糖乳杆菌,其中德氏乳杆菌降解亚硝酸盐的能力最强,MRS培养基中生长24 h,其亚硝酸盐降解率为87.7%,发酵罐恒定pH值6.0,培养24 h,其降解率为98.9%。德氏乳杆菌具有良好的耐酸、耐盐与快速产酸能力,可作为果蔬发酵剂进一步开发利用。     

贵州酸肉中具有高亚硝酸盐降解和耐受能力乳酸菌的筛选与鉴定

从贵州自然发酵的酸肉中分离出19株乳酸菌,选择在MRS培养基中培养24 h的降亚硝酸盐能力最强的3株乳酸菌,经16S r DNA分子鉴定为植物乳杆菌CMRC 3、戊糖片球菌CMRC 7和植物乳杆菌CMRC 19。在模拟肉类发酵的条件下,研究其降解、耐受亚硝酸盐和硝酸盐的能力。3株乳酸菌都具有较好的亚硝酸盐降解能力,发酵120 h后分别降解了65.7%~86.3%的亚硝酸盐;然而它们的硝酸盐降解能力都不显著。CMRC 7和CMRC 19耐受亚硝酸盐的性能最强,最高活菌数分别为8.20lg(CFU/m L)和8.11lg(CFU/m L);这3株菌都具有较好的硝酸盐耐受性,最高活菌数分别为8.21,7.93lg(CFU/m L)和8.20lg(CFU/m L)。试验结果表明,从酸肉中筛选出的这3株乳酸菌都有较强的亚硝酸盐降解能力,同时也有较好的硝酸盐和亚硝酸盐耐受性能,可开发成肉类专用发酵剂。     

酸驼乳发酵乳酸菌菌株的筛选及其发酵特性研究

对新疆自然发酵骆驼乳中乳酸菌菌群进行分离鉴定得到五株乳酸菌,其中乳杆菌3株分别为瑞士乳杆菌(Lactobacillus helveticus)、植物乳杆菌(Lactobacillus plantrum)和开菲尔乳杆菌(Lactobacillus kefiri),片球菌2株分别为乳酸片球菌(Pediococcus acidilactici)戊糖片球菌(Pediococcus pentosaceus)。分离鉴定出的五株乳酸菌在培养基中生长良好,其活菌数在培养16 h后能达到109 CFU/m L。将传统酸奶发酵剂接种于骆驼乳中并于42℃条件下培养,发现其在骆驼乳中能较好地产酸,其添加量在0.1%时最适。将筛选到的乳酸菌制备成生产发酵剂与传统酸奶发酵剂复配,得到瑞士乳杆菌组的复配效果最佳,具有最优的产酸效果,在经过6 h发酵后p H值降到4.5左右,酸度达到85oT,且制备的发酵骆驼乳具有最好的感官品质,其感官评分明显高于其他菌株复配进行发酵的骆驼乳产品。因此,可将0.1%传统酸奶发酵剂与筛选到的瑞士乳杆菌制备的生产发酵剂复配应用于酸驼乳发酵。     

泡菜中亚硝酸盐降解乳酸菌的筛选与鉴定

目的从泡菜中筛选亚硝酸盐降解能力强的乳酸菌。方法采用平板涂布法和平板划线法从泡菜中分离若干株产酸菌株,从中筛选出产酸能力强、生长速度快、亚硝酸盐降解性能高的菌株。对优选菌株进行了形态学、生理学鉴定,测定其16S rRNA基因序列,并检测其耐盐能力、糖谱、产酸能力、抑菌性能及亚硝酸盐降解能力。结果该产酸菌株为植物乳杆菌(Lactobacillus plantarum),此菌在37℃、7.0%NaCl及0.1%NaNO2条件下生长良好;37℃MRS培养基培养24 h后pH下降为3.96;该菌株在以葡萄糖、蔗糖、果糖和菊粉为碳源的LB培养基中生长良好;具有较高的乳酸生产能力,对亚硝酸盐的降解率高达91.3%。结论从泡菜中筛选的乳酸菌株具有较高的耐盐能力及亚硝酸盐降解能力。     

培养基中3株乳酸菌对7种有机磷农药的降解作用

利用含有7种有机磷农药的脱脂乳培养基培养3株乳酸菌,然后利用丙酮-乙腈(体积比为1:4)提取液萃取脱脂乳培养基中的7种有机磷农药,气相色谱法测定这些有机磷的含量,并以此计算有机磷的降解动力学常数.结果表明,3株乳酸菌对有机磷农药均有一定的降解效果,可不同程度减少了7种有机磷农药的半衰期,其中植物乳杆菌1.0343的作用...     

新疆传统奶酪中抗氧化乳酸菌筛选及培养条件优化

新疆传统奶酪中富含大量乳酸菌,为了得到具有抗氧化活性的乳酸菌,该文以新疆传统奶酪中筛选出的161株乳酸菌为研究对象,通过测试过氧化氢耐受性、羟自由基清除能力、超氧阴离子自由基清除能力、还原能力、金属离子螯合能力、DPPH自由基清除能力,综合评估菌株的抗氧化性。结果表明,有12株乳酸菌具有较高抗氧化活性,其中菌株S2-7发酵上清液对羟自由基、超氧阴离子自由基、DPPH自由基清除能力较好,分别为95.28%、90.17%、88.22%;菌株B6-4、S4-14菌悬液具有较好的还原能力及亚铁离子螯合能力,分别为92.75%、95.85%。将这12株乳酸菌经过模拟人工胃肠液及胆盐耐受测定,8株展现出良好的耐受性。经16S rDNA鉴定,7株为乳酸片球菌;1株为干酪乳杆菌。优化其培养条件,得到培养基初始pH(6.5～7.5)、培养时间(18～28 h)、培养温度(37～42℃)、接种量(2%～3%),研究结果将对优质菌种的开发提供数据支持。     

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