产海藻糖合酶菌株发酵培养基的研究

在已筛选出产海藻糖合酶菌株———恶臭假单胞杆菌的基础上 ,研究了该菌株最佳发酵培养基。恶臭假单胞杆菌H76的最适碳源为麦芽糖和葡萄糖 ,最适氮源为蛋白胨和酵母粉 ,无机盐为MgSO4 ·7H2 O ;该菌株产酶最佳培养基配方为 :麦芽糖 3 % ,葡萄糖 3 % ,Mg SO4 7H2 O 0 2 % ,蛋白胨 2 % ,酵母粉 0 7%。     

响应面法优化巨大芽孢杆菌Y103产普鲁兰酶的培养条件

在玉米秸秆腐殖质土壤中筛选分离得到一株巨大芽孢杆菌（Bacillus megaterium）Y103,采用单因素试验、响应面法优化巨大芽孢杆菌Y103产普鲁兰酶的培养条件。结果表明,最佳培养基配方为糯米淀粉8.5 g/L,酵母膏13.3 g/L,蛋白胨 26.7 g/L,KH2PO4 0.5 g/L,MgSO4·7H2O 0.1 g/L,MnSO4·7H2O 0.05 g/L,NaCl 2.0 g/L。最佳发酵条件为初始pH8.8,发酵温度21 ℃,发酵时间55 h。在最优条件下,普鲁兰酶酶活力为（0.77±0.03） U/mL,是优化前的3.21倍。该酶的最适作用温度为50 ℃,最适pH为8.0,其水解普鲁兰糖的产物中有大量麦芽三糖和麦芽六糖,表明其为一种新颖的II型普鲁兰酶,在洗涤剂、高麦芽糖浆和麦芽六糖的生产中有着潜在的巨大利用价值。     

乳酸乳球菌L9产类细菌素lactococcin GJ-9发酵条件的研究

对产类细菌素乳酸乳球菌L9的发酵条件进行了研究。结果表明 :产类细菌素最适培养基为MRS,培养基的最适初始pH值为 6 5 ;产类细菌素最适温度为 32℃ ;0 2 %Tween 80最适类细菌素的产生。并通过正交试验确定L9产类细菌素的最佳培养基为 :大豆蛋白胨 1 %、酵母膏1 5%、葡萄糖 1 2 5 %、K2 HPO40 2 %、NaAc 0 5 %、MgSO4·7H2 O 0 0 58%、柠檬酸三铵 0 2 %、MnSO4·4H2 O 0 0 0 5 %、Tween 80 0 2 % ;初始 pH6 0。经过优化 ,发酵液效价提高了 61 0 7%。     

白灵菇产胞外多糖液体培养条件优化

以菌丝体生物量及发酵液中胞外多糖(exopolysaccharides,EPS)含量为指标对白灵菇产胞外多糖的液体培养基组成和发酵条件进行了优化。结果表明,最适碳源是麦芽糖,最适氮源是酵母膏。正交实验确定最佳培养基组成为麸皮200g/L,麦芽糖25g/L,酵母膏3g/L,KH2PO41g/L,MgSO·47H2O1g/L。最佳发酵条件为起始pH8.0,培养温度25℃,摇床转速160r/min,装液量100mL/250mL,接种量0.50cm2菌种块,发酵时间4d。在此条件下,白灵菇菌丝体生物量(0.413g/100mL)及胞外多糖含量(2403.2mg/L)分别是对照(0.177g/100mL和664.533mg/L)的2.3倍和3.6倍。     

长双歧杆菌22-5胞外多糖(EPS)合成条件的优化

针对筛选出的产胞外多糖优良菌株长双歧杆菌22-5,采用单因素及正交试验,对其培养基组分及培养条件进行优化,确定生产EPS的最适培养基组成为蔗糖20g,大豆蛋白胨10g,MnSO4为5g,牛肉膏10g,乙酸钠5g,柠檬酸铵2g,K2HPO4为2g,MgSO4·7H2O为0.58g,吐温80为1mL,蒸馏水1000mL;最适培养条件为初始pH值为5.0,20℃厌氧培养20h。优化后菌株22-5EPS的产量可提高到1000mg/L,是为优化前的3倍。     

醋杆菌产纤维素发酵培养基的优化

本文在已筛选出在摇瓶培养条件下高产细菌纤维素菌株--醋杆菌C2的基础上,研究了不同碳氮源及无机盐对该菌株产纤维素的影响,并优化了该菌株产纤维素的最佳培养基。醋杆菌C2的最适碳源为蔗糖,D-甘露糖醇,最适氮源为蛋白胨,酵母粉,无机盐为MgSO4•7H2O和柠檬酸三钠;经正交试验确定该菌株产酶最佳培养基配方为:蔗糖7%,酵母膏0.7%,蛋白胨1.1%,MgSO4•7H2O 0.2%,柠檬酸三钠0.1%。使用优化后的培养基配方,醋杆菌C2的纤维素产量可达9.5g/L。     

重组麦芽糖转葡萄糖基酶工程菌发酵条件的优化

对重组麦芽糖转葡萄糖基酶工程菌的发酵条件进行优化,通过单因素试验确定该菌株产麦芽糖转葡萄糖基酶的最佳发酵培养基为：糖蜜0.025g/mL、胰蛋白胨0.015g/mL、MgSO4 ·7H2O与K2HPO4的质量为7:1、FeSO4 ·7H2O 0.5g/L;以葡萄糖氧化酶法为指标测得最佳摇瓶发酵条件为：装液量100mL/250mL、转速200r/min、接种量5%、初始pH 7.0、最佳温度37℃、诱导阶段OD600nm=0.6、诱导温度30℃、诱导时间5h、诱导剂异丙基-β-D-硫代吡喃半乳糖苷(IPTG)浓度1mmol/L。经优化,重组麦芽糖转葡萄糖基酶的酶活力可达950U/mL,比初始条件下提高了近7倍。     

灵芝菌丝液体深层发酵培养基的研究

利用液体深层发酵方法进行灵芝菌丝发酵最佳培养基的确定。通过单因素实验研究了可溶性淀粉、葡萄糖、蛋白胨、麸皮、MgSO4·7H2O、KH2PO4对液体深层发酵灵芝菌丝生长的影响,并通过单因素试验和正交试验确定了灵芝液体深层发酵的最适培养基配比为可溶性淀粉1%,葡萄糖2.5%,蛋白胨0.1%,麸皮0.5%,MgSO4·7H2O0.015%,KH2PO40.1%。发酵6d干菌体得率为19.91g/L。     

海藻糖合成酶产生菌筛选、鉴定及其产酶特性

以麦芽糖为唯一碳源高盐培养基,经高温培养,从温泉水样及其附近土壤中筛选得到一株菌株T2,经过生物合成途径初步验证,该菌株产海藻糖合酶,能够通过海藻糖合成酶（TreS）途径将麦芽糖转化为海藻糖。菌株T2为革兰氏阳性菌,杆状,有芽孢,经过生物学鉴定,将其初步鉴定为芽孢杆菌属（Bacillus sp.）。对其产海藻糖合酶的酶学性质进行了研究：酶反应最适作用温度为60 ℃,在60 ℃条件下保温100 min仍能保持酶活性80.7%;最适作用pH值为7.0,在pH 6.0～7.5范围内稳定。采用正交试验对其发酵培养基配方进行了优化研究,确定了最佳的培养基组成为牛肉膏3.0 g/L,麦芽糖20.0 g/L,蛋白胨7.5 g/L,无机盐（K2HPO4＋NaH2PO4＋MgSO4·7H2O）3.0 g/L。在此条件下,菌株T2产海藻糖合酶酶活力达到310.6 U/L。     

产海藻糖合成酶SH-110号菌的培养特性及其发酵条件的研究

在筛选出产海藻糖合酶菌株SH-110基础上研究其培养特性和最佳的发酵条件.优化培养基组成为:1%麦芽糖、0.5%蛋白胨、0.2%牛肉膏、0.1%K2HPO4、0.12%NaH2PO4.其最佳的发酵条件为:最佳发酵温度为36℃,最佳发酵pH值为7.2,选取最佳装液量为15 mL,发酵终点确定为48h.     

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