短双歧杆菌增殖培养基的优化研究

本研究针对短双歧杆菌的营养需要,采用正交实验设计优化增殖培养基,结果表明,酵母膏是短双歧杆菌的显著影响因素, 最佳的优化培养基配比是酵母膏0.9%,胰蛋白胨0.6%,大豆蛋白胨0.6%,葡萄糖0.6%,双歧因子0.2%,生长因子10%.用经优化的增殖培养基配方测定短双歧杆菌的生长曲线及其pH的变化,确定该菌增殖培养的最适终止时间约为18h,此时平板菌落计数的菌数可高达1.5×1010cfu/ml.     

促双歧杆菌生长培养基的优化

为了促进双歧杆菌更好地生长,根据双歧杆菌的营养需求,采用正交试验,优化MRS培养基中的碳源、氮源和增殖因子。试验结果显示,优化MRS培养基的最佳配比是:大豆蛋白胨0.37%、胰蛋白胨1.13%、葡萄糖1.0%、酵母浸出粉0.7%、胡萝卜汁7.5%、番茄汁7.5%、玉米浆5.0%。双歧杆菌在优化MRS培养基中所得菌数是普通MRS培养基中的10倍。     

双歧杆菌菊芋复合汁增菌培养基的优化筛选

以菊芋为主要原料,以两歧双歧杆菌(Bifidobacterium bifidus,Bbm)和长双歧杆菌(Bifidobacteriu.longum,Blm)为试验菌株,研究了菊芋汁基础培养基中添加单一营养因子对Bbm细胞生长量的影响.利用正交试验优化筛选出Bbm菊芋复合汁增菌培养基;利用优选的菊芋复合汁增菌培养基对Blm进行验证性增菌试验.结果表明大豆蛋白胨、牛肉浸膏、酵母膏、玉米浆可显著促进Bbm的细胞增殖(P＜0.01),而磷酸氢二钾既能促进Bbm生长,又有缓冲培养基pH值的作用;利用L934筛选出Bbm菊芋复合汁增菌培养基的最佳配比是在10 Brix菊芋汁中添加0.6%大豆蛋白胨、0.9%牛肉浸膏、0.3%酵母膏、0.4%玉米浆、0.2%磷酸氢二钾.在菊芋复合汁增菌培养基中,经37℃培养12 h,Bbm活菌数6.80×109 cfu/mL,Blm活菌数6.65×109 cfu/mL,较时照菊芋汁培养基的活菌数分别提高了13.5倍和7.63倍;较实验室常用的改良MRS培养基的成本降低了2770元/t.     

保加利亚乳杆菌番茄复合汁增菌培养基的优选研究

研究了在番茄汁基础培养基中添加不同营养物质对保加利亚乳杆菌生长的影响,进一步采用正交试验优化筛选了保加利亚乳杆菌L.b-S1的增殖培养基。结果表明,在番茄汁基础培养基中添加胰蛋白胨、酵母膏、碳酸钙可显著促进试验菌株的细胞生长(P<0.01);利用L933正交试验筛选出增殖培养基的最佳配比为:在番茄汁基础培养基中添加0.5%酵母膏、1.0%胰蛋白胨、0.3%碳酸钙;试验菌株在增殖培养基中经37℃培养18h,活菌数可达为2.25×1010mL-1,较液体MRS培养基的活菌数(4.98×108mL-1)提高了45.18倍,成本较液体MRS培养基降低1500元/t。为工业化大规模培养乳酸菌并研制开发直投式酸奶发酵剂提供了经济廉价的增菌培养基。     

响应面法优化乳双歧杆菌Z-1高密度发酵培养基

采用响应面法优化乳双歧杆菌Z-1发酵培养基。以改良MRS为基础培养基,通过单因素试验、PB试验、最陡爬坡试验得到影响乳双歧杆菌Z-1菌量的显著因素及最优响应值区间。试验结果表明,乳糖、胰蛋白胨和玉米浆为乳双歧杆菌最适宜碳源、氮源和生长因子;磷酸氢二钾、硫酸镁、L-半胱氨酸盐酸盐和玉米浆对菌量影响显著。经响应面设计优化得到最优高密度培养基为:乳糖2%、胰蛋白胨1%、酵母膏0.5%、牛肉膏1%、磷酸氢二钾0.322 8%、柠檬酸铵0.26%、硫酸镁0.097 2%、硫酸锰0.005%、吐温80 0.15%、L-半胱氨酸盐酸盐0.245 1%、玉米浆8.129 8%。     

中心组合设计优化两歧双歧杆菌BB01增殖培养基

为了提高两歧双歧杆菌培养液中的活菌数,采用中心组合设计对其增殖培养基进行了优化。在前期单因素试验的基础上,首先通过Plackett-Burman试验筛选出了影响两歧双歧杆菌生长的4个主因子,再通过中心组合设计试验及响应面分析确定了4个主因子的最佳浓度为:三氯化铁、水苏糖、蒺藜提取液和pH分别为0.012 g/L、8.0 g/L、2.5%和6.90,用优化后的增殖培养基培养两歧双歧杆菌,24 h后其培养液OD600为1.398±0.007,比优化前提高了24.28%。     

双歧杆菌麦芽复合汁增菌培养基优选的研究

选择麦芽汁为主要原料，以两歧双歧杆菌Bbm和长双歧杆菌Blm为实验菌株，研究了麦芽汁基础培养基中添加单一营养因子对Bbm菌细胞生长量的影响，进一步利用正交试验优化筛选出Bbm菌麦芽复合汁增菌培养基；利用优选的麦芽复合汁增菌培养基对Blm菌进行验证性增菌试验。结果表明：大豆蛋白胨、牛肉浸膏、酵母膏、玉米浆可显著促进双歧杆菌Bbm的细胞增殖（p〈0．01），而磷酸氢二钾既能促进Bbm生长，又有缓冲培养基pH值的作用；利用L9（3^4）筛选出Bbm的麦芽复合汁增菌培养基的最佳配比为：在10°麦芽汁中添加0．3％大豆蛋白胨，0．6％牛肉浸膏，0．5％酵母膏，0．4％玉米浆，0．2％磷酸氢二钾，在麦芽复合汁增菌培养基中，经37℃培养12h，Bbm活菌数3．84×109CFU/ml，Blm活菌数达到3．90×109CFU／ml，较对照麦芽汁培养基的活菌数分别提高了8．17倍和8．14倍，较实验室常用的改良MRS培养基的成本降低1000元/吨。     

菊芋汁双歧杆菌培养基的筛选优化

本文研究了双歧杆菌在菊芋汁中的生长状况,考察了添加不同物质对双歧杆菌生长的影响。结果表明,双歧杆菌在菊芋汁中能够良好生长,在菊芋汁中添加胰蛋白胨、牛肉膏、玉米浆、半胱氨酸盐、大豆蛋白胨对双歧杆菌促进生长作用极显著。采用正交试验法确定了菊芋汁双歧杆菌培养基的配方:菊芋汁+0.3%玉米浆+0.5%大豆蛋白胨+0.025%半胱氨酸盐酸盐,双歧杆菌在其中的活菌数可以达到109以上。     

嗜酸乳杆菌的筛选及培养基的优化

通过模拟正常人体胃内状态,筛选出10株耐酸耐胆盐的嗜酸乳杆菌。针对嗜酸乳杆菌的营养需要,采用正交实验优化基础培养基及增殖因子的用量,得出最佳基础培养基配比:蛋白胨1%,葡萄糖0.5%,大豆低聚糖1.5%,酵母膏1.0%(均为质量分数);最佳增殖因子添加量为西红柿汁12%。最后使用优化出的增菌培养基测定生长曲线,同时测定pH值和OD值的变化确定增菌培养终止时间为16h,通过平板菌落计数,此时菌数可达2.2×1012mL-1。     

婴儿双歧杆菌发酵培养基组成的优化

针对婴儿双歧杆菌的营养需要,分别采用单因素试验和正交试验,优化培养基成分及用量。得出最佳发酵培养基(CPT)配比:大豆蛋白胨1.67%,酪蛋白胨0.83%,乳糖0.5%,酵母浸出粉0.5%,低聚糖0.7%,胡萝卜汁15%。最后测定婴儿双歧杆菌在发酵培养基中的生长曲线,并同时测定pH和吸光值的变化,确定发酵终止时间为12h,此时菌数可达2.18×109cfu/ml。     

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