产类细菌素乳酸菌筛选及类细菌素的特性

从泡菜中分离到一株产生类细菌素的乳酸菌,通过双层平板扩散试验测试这种类细菌素的抑菌活性,并且研究其部分生物学特性.经形态特征、生理生化特征和API试剂条鉴定,该菌为植物乳杆菌(Lactobacillus plantarum).产生的类细菌素对所试菌株具有明显的抑制作用,排除有机酸、过氧化氢和糖类的干扰后,仍有抑菌活性.这种类细菌素对热、酸碱稳定,微量的K+,Mn2+,Mg2+能增强其抑菌活性,Fe2+和Cu2+能减弱活性;可被4种蛋白酶失活,表明这种类细菌素是一种蛋白质活性物质.该类细菌素的作用方式是杀菌,抑菌谱广,可抑制多种革兰氏阳性细菌、革兰氏阴性细菌和真菌的生长.     

嗜酸乳杆菌产类细菌素Lactobacillin NX2-6的初步研究

从内蒙古传统乳制品酸马奶中筛选出1株产生具有广谱抑菌活性物质的嗜酸乳杆菌NX2-6。在排除酸性产物和过氧化氢的干扰后,菌株NX2-6所产生的类细菌素对金黄色葡萄球菌等革兰氏阳性菌和大肠杆菌等革兰氏阴性菌及米曲霉等真菌具有较强的抑制作用;经胰蛋白酶、胃蛋白酶、蛋白酶K处理后发酵液抑菌活性明显下降,但仍具有较强的抑菌活性,对α-胰凝乳蛋白酶抗菌活性没有显著变化,因此表明该抗菌活性物质为蛋白类物质或非单一物质。在酸性条件下它具有很好的热稳定性,pH2.0时活性最强,中性或碱性条件下不具有抗菌活性,抑菌活性pH值范围在2.0-5.0。此抗菌物质不同于一般细菌素,属于类细菌素,命名为Lactobacillin NX2-6。菌株NX2-6产物在生防、食品具有潜在的应用价值。     

酸菜中具有抑菌活性乳酸菌的分离鉴定及其产细菌素特性

目前已有研究陆续从不同的乳酸菌中分离到细菌素,但是这些细菌素存在着抑菌谱窄的问题,寻找广谱抗菌性能的新一代细菌素具有重要的理论价值和应用前景。以市售保质期较长的8种不同品牌的酸菜为材料,将青霉菌作为指示菌,通过抑菌实验筛选出一株能产生抑菌物质的菌株L3,经过生理生化鉴定、16S rDNA测序分析确定该菌株为植物乳杆菌(Lactobacillus plantarum),故命名为植物乳杆菌L₃,NCBI序列号为MT781360。该菌株在MRS培养基中于37℃培养18~24h时产细菌素L3的抑菌活性最强。将该培养上清液采用乙酸乙酯萃取,葡聚糖凝胶柱Sephadex G-50过滤分离纯化,再经Trinice-SDS-PAGE电泳结果显示,细菌素L3的分子质量约为4~5kDa。细菌素L3对蛋白酶敏感,但其活性不受过氧化氢酶的影响,初步结果显示细菌素L3为蛋白质类物质。细菌素L3在60~100℃ 处理20min或121℃处理15min仍具有较高的抑菌活性,pH值2~10范围内有良好的稳定性;对革兰氏阳性菌和革兰氏阴性菌以及部分真菌具有抑菌活性。植物乳杆菌L₃分泌的细菌素L3除了具备现有细菌素的稳定性和对革兰氏阳性细菌的杀菌能力以外,还能对革兰氏阴性细菌和真菌起到抑菌效果,这对于易被真菌污染导致腐败的果蔬类产品及乳制品的保藏具有重要意义,希望研究可为具有广谱抗菌性能的天然防腐剂的生产提供新的菌种。     

弗氏链霉菌S-221变种发酵液的抗菌活性及稳定性研究

采用管碟法和抑制菌丝生长法测定了弗氏链霉菌S-221发酵液对细菌和10种植物病原菌的抑菌活性.结果表明,发酵液对革兰氏阳性细菌、革兰氏阴性细菌都有很强的抑菌活性,同时对10种植物病原菌、真菌也具有很强的抑菌活性.通过对发酵液稳定性的初步研究,结果表明发酵液中的抑菌活性物质对温度、紫外光和pH值稳定.     

一株从泡菜中分离的产细菌素乳杆菌的鉴定及细菌素特性研究

从泡菜中分离的329 株乳酸菌中,筛选出一株产细菌素的乳酸菌,编号为SD-22。经生理生化实验鉴定为短乳杆菌(Lactobacillus brevis)。在排除过氧化氢干扰和有机酸抑菌作用后,brevicin SD-22 对革兰氏阳性细菌和革兰氏阴性细菌具有较好的抑制作用,对部分真菌也有抑制作用,但对酵母菌和青霉无抑制作用,具有良好的热稳定性和pH 值稳定性,经胰蛋白酶、胃蛋白酶和蛋白酶K 处理后抑菌活性完全消失,对α- 淀粉酶不敏感。因此初步认为该菌株是一株产广谱细菌素的乳酸菌。     

西藏开菲尔中抑菌活性物质的提取及抑菌效果研究

采用水提取西藏开菲尔（Kefir）中的抑菌活性成分,用K—B纸片法测定提取物对常见的革兰氏阳性和革兰氏阴性细菌、部分真菌和霉菌的抑菌活性,并检测了用不同的pH、温度、光照处理后提取物的抑菌效果。研究结果表明,Kefir提取物对大肠杆菌、金黄色葡萄球菌和枯草芽孢杆菌、黄曲霉和啤酒酵母均有明显的抑制效果,最小抑菌浓度（MIC）在6．25～12．5mg／mL之间,与尼生素相比,抑菌效果相当,抑菌谱更广;提取物在酸性和中性条件下抑菌活性稳定．而在碱性条件下抑菌活性减弱,且具有较好的热稳定性和光稳定性。     

国产Nisin部分特性的研究

研究温度、pH、蛋白酶、保存条件对国产Nisin抑菌活性的影响,以及抑菌谱等,结果表明温度、pH会显著影响Nisin活性,在酸性条件下,Nisin对温度较稳定,随PH值的增加,温度越高,Nisin活性下降越显著,温度越低越有利于保存,干制品比溶液易保存,国产Nisin对胃蛋白酶不敏感,但对胰蛋白酶敏感,国产Nisin对革兰氏阳性细菌有抑制作用,而对革兰氏阴性细菌、霉菌和酵母没有作用。     

1株乳酸链球菌素产生菌的筛选鉴定及其抑菌特性的研究

从白菜叶上分离得到21株对乳酸链球菌素(Nisin)有抗性的乳酸菌株,采用杯碟法从中筛选得到抑菌活性较强的菌株T0625,经鉴定该菌株为乳酸乳球菌乳酸亚种(Lactococcus lactis subsp.Lactis)。经测定,发酵液经加热处理,在低pH条件下能够保持较好的抑菌活性,对革兰氏阳性细菌具有明显的抑制作用,但对革兰氏阴性细菌、酵母菌和霉菌不表现抑制作用。研究还证实,T0625的发酵产物的抑菌活性不受胃蛋白酶和胰蛋白酶的影响。经提取纯化,确定抑菌物质为乳酸链球菌素。     

一株产细菌素乳杆菌的鉴定及其细菌素编码基因的获得

应用双层平板打孔法,从自制樱桃酒里分离的乳杆菌中筛选到一株对革兰氏阳性细菌和革兰氏阴性细菌均有明显抑制作用的菌株,命名为LD 1.0008。通过API 50 CHL糖发酵产酸实验、16S rDNA基因序列分析及其特异性recA基因多重聚合酶链式反应（polymerase chain reaction,PCR）,鉴定LD 1.0008为植物乳杆菌。排除有机酸的干扰,用多种蛋白酶处理后,其抑菌活性均有明显降低,而用过氧化氢酶处理后其抑菌活性基本不变,从而确定LD 1.0008所产生的抑菌物质为细菌素。使用已报道的10 对植物乳杆菌细菌素基因片段设计的引物对菌株LD 1.0008进行PCR扩增,发现其至少含有4 个植物乳杆菌素相关编码基因,即plnD、plnO、plnV和plnW。     

产细菌素嗜盐四联球菌的筛选及鉴定

从传统露天酿造工艺的酱油中分离出12株乳球菌,对其进行形态、生理生化特性研究及16S rDNA序列分析,鉴定为嗜盐四联球菌。在排除酸作用后,WZ-3菌株发酵液对革兰氏阳性和革兰氏阴性细菌具有较好的抑菌活性,经胃蛋白酶、胰蛋白酶处理后,发酵液抑菌活性略有下降。因此初步认为该菌株为产细菌素的嗜盐四联球菌。     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.