蜢子虾酱中度嗜盐菌的分离、鉴定及特性研究

从蜢子虾酱中分离纯化鉴定了一株中度嗜盐菌MKY20,对其进行了形态学和生理生化特性研究;通过测定其16S rDNA序列并通过系统发育分析对该菌株进行了分子水平的鉴定.试验结果表明,嗜盐菌株MKY20为革兰氏阳性菌,菌体可以产芽孢,呈杆状,菌体大小为(0.6μm～0.8μm)×(2.0μm～4.0μm);生理生化特性研究表明菌株MKY20最适盐度为3％,最适生长温度为28℃～34℃,最适pH值为7.0;系统发育分析将该菌初步鉴定为枝芽孢杆菌属(Virgibacillus)中的盐脱氮枝芽胞杆菌(Virgibacillus halodenitrificans).该研究将为进一步研究虾酱中的嗜盐菌的菌落结构提供参考,为防止嗜盐菌污染食品提供帮助.     

调味品酿造微生物的实验技术(续)

(二)形态特征 1.麦穿汁培养基25℃,培养3天观察:细胞圆形、卵圆或卵圆～长卵形。圆～卵形大小为(2.6～5.2)×(3.4～6.2μ,卵～长卵形大小为(2.6～4.5)×(3.5～10.5)μ。细胞成小群的粘在一起(如图3)。培养基底部有沉渣,有时菌体在培养基液面形成小的环。     

腌制咸鱼中嗜盐菌分离鉴定及特性研究

从腌制咸鱼中筛选出一株中度嗜盐菌CNY0820,该菌革兰氏阳性反应,杆状,宽度0.6μm～1μm,长度1.5μm～2.9μm,产芽孢,分泌淀粉酶,过氧化氢酶和酯酶,明胶水解反应阳性,氧化酶、硝酸盐还原、MR和VP反应均为阴性。生长盐度为0%～25%(NaCl,w/v),最适盐度0.5%;温度范围20℃～45℃,最适温度40℃;pH值为4.0～12.0,最适pH值为8.0。经16SrDNA序列比对及系统发育树分析,该菌属于Halobacillus,但又与进化距离最近的Halobacillus trueperi存在一定差异。该菌的研究对腌制食品中嗜盐菌分类及防止嗜盐菌污染有一定意义。     

网印技术问答

丝网的理论下墨量是怎样确定的?丝网的理论下墨量是指未绷网时每平方米能透过多少平方厘米的油墨量,用V表示。V=M0×(M×1m)2×(丝网的厚度)例如:120-34Y丝网:M0=45μm=0.0045cm(网孔的开口)M = 120×100cm(1m长丝网的目数)网厚度=55μm=0.0055cmV = 0.00452×(120×100)2×0.0055 = 16.038(cm3/m2) 但是,在实际生产中:(1)丝网必须绷网固定在网框上,由于网丝受拉伸力的作用,改变了丝网的丝径和网孔的宽度,当然厚度也随之改变,但总的下墨量体积与未绷网前的下墨体积相近。(2)丝网制作成网版后,在正常刮刀压力下,图文上的下墨量因网版上…     

一株能转化β-氨基丙腈生产β-氨基丙酸的菌株G20的分离与鉴定

从浙江杭州地区的土壤分离、筛选到1株能转化β-氨基丙腈生产β-氨基丙酸的苗株G20。对该菌进行形态特征观察、生理生化测定、Biolog GP2鉴定以及16S rDNA序列相似性和系统发育分析,确定G20为红串红球菌(Rhodococcus erythropolis)。其特征:培养48h后菌落呈桔黄色,干燥。隆起,圆形;电镜观察.为长杆菌,大小(0.3～0.8)μm×(2～5)μm;革兰氏阳性菌;能较强利用Biolog系统95种碳源中的25种,与红串红球菌的相似性100%,相似性指数为0.58;以16S rDNA序列为基础构建包括15株邻近种属细菌在内的系统发育树,其中与红串红球菌的相似性最高.     

1996年度鉴定投产的主要棉纺织机械器材新产品（二）

12　HEG203型立式卷纬机由河北省邯郸第二纺织机械厂设计制造。它在织造准备工程中,将筒子纱卷绕成纬纱管纱,供织机用。该机的主要技术参数:(1)形式:双面竖锭式;(2)锭数:92、156、220、252、284、316(锭);(3)锭距:70mm;(4)导纱动程:46mm;(5)最大卷绕直径:32mm;(6)最大卷绕高度:165mm;(7)备纱长度:4m～10m;(8)机器重量:2.2t;(9)主电机:2.2kW;(10)机器(156锭)外形尺寸(长×宽×高):6600mm×760mm×1950mm。该立式卷纬机适用于9.7tex～86tex的纯棉、涤棉低弹长丝、中长纤维等品种,机器技术水平属国内先进水平。13　︿-1100型整经机由沈阳纺织…     

加工单元操作对胡萝卜汁理化指标和果肉颗粒大小的影响

研究了加工单元操作对胡萝卜汁理化指标和果肉颗粒大小的影响。结果表明,均质和杀菌能显著减少胡萝卜汁中类胡萝卜素含量,增加了可溶性固形物和粘度,并且降低了pH,通过离心和均质能显著降低浊度,离心后汁的色泽L、a和b值都增加了。通过扫描电镜(SEM)观察发现,离心、均质和杀菌后,果肉颗粒变小,其大小分别为(37.5×45)、(7.5×10.5)和(4.75×5.4)μm。     

HPLC同时测定心可宁胶囊中羟基红花黄色素A和丹酚酸B的含量

目的建立同时测定心可宁胶囊中羟基红花黄色素A和丹酚酸B含量的方法。方法采用高效液相色谱法(HPLC),色谱柱为Agilent Zorbax Extend C_(18)柱(250 mm×4.6 mm,5μm),柱温30℃,流动相为甲醇-0.5%磷酸(35:65),流速1.0 ml/min,检测波长403 nm(羟基红花黄色素A)、286 nm(丹酚酸B),进样量10μl。结果羟基红花黄色素A在0.1184～0.8880μg的范围内呈良好的线性关系(r=0.9994),丹酚酸B在0.8390～6.2925μg的范围内呈良好的线性关系(r=0.9998);羟基红花黄色素A平均加样回收率为99.17%(n=6),RSD为0.87%,丹酚酸B平均加样回收率为99.41%,RSD为0.87%。结论该方法操作简便、准确、重复性好,可用于心可宁胶囊的质量控制。     

老窖泥讲座(二) 第二节 己酸菌

一形态杆菌,营养菌体呈梭状。菌体健壮者,5～9×0.8～1.0μm,瘦弱者约2～3×0.4～0.6μm。营养细胞单个或成对,通常不形成链,个别有成串长链。生荚膜,周生鞭毛,健壮者游动活泼。芽孢端生,在末端处生有椭圆形孢子,引起杆菌末端膨胀而呈鼓锤状,故亦有鼓锤状菌之称。在培养基上培养2～3天镜检可见芽孢。成熟孢子约1.2～1.5μm。细胞各处有易染的小粒体,能被碘染色。革兰氏染色阴性。     

谷氨酸棒杆菌S9114中谷氨酸脱氢酶的初步研究

本研究以谷氨酸生产菌种S9114 为材料 ,对GDH的辅酶专一性、最适温度、最适pH和动力学参数进行了研究 ,结果发现谷氨酸生产菌S9114 细胞内含有两种GDH ,其GDH不仅能以NADPH为辅酶 ,而且能以NADH为辅酶 ,其Km值分别为 12 .4mmol/L和 1.5 8× 10 -3 mmol L ,Vmax分别为2 .4 8μmol min .ml和 5 .2 5 μmol min .ml,其最适反应温度为 4 2℃和 82℃ ,最适反应pH分别为 7.5和8.0 ,并对热比较稳定。经DEAE柱层析分析也表明谷氨酸生产菌S9114 细胞内同时存在两种GDH。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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