宜宾多粮浓香型酒厂内细菌多样性及分布的研究（二）

对宜宾多粮浓香型酒厂内生产过程环境中分离到的24株优势菌株进行DNA提取扩增测序,对其16SrDNA序列分析表明,其中13株为Bacillus属,9株分属于Lysinibacillus属、Staphylococcus属、Rummeliibacillus属,Brevibacillus属、Brachybacterium属,还有2株菌与数据库中模式菌株相似性低于97%,很可能代表着新类群.利用现代生物技术探索对酿酒相关细菌优势菌株的分子生物学信息,对浓香型白酒酿造过程中优势细茵区系的变化进行探索,探讨多粮浓香型白酒酿造过程中优势细菌对白酒风味物质的影响.     

酿造细菌分解纤维素的初步研究

为了解宜宾浓香型白酒酿造环境中分离到的细菌对纤维素的分解能力,进而探讨其在固态发酵过程中对谷物纤维的分解情况,采用平板培养法,对分离自宜宾浓香型白酒产区的530株细菌分解纤维素的能力测试.结果表明分离自曲房、糟醅中的细菌可分解纤维素菌所占比例较高;Bacillus cereus、Bacillus methylotrophicus、Bacillus aryabhattai、Bacillus tequilensis、Bacillus thuringiensis5个种属的细菌分解纤维素能力较其他强.研究表明酿造细菌分解纤维素能力与来源和种属有密切的关系.     

茅台镇酱香型白酒酿造大曲及环境中可培养细菌多样性及功能分析

通过传统微生物分离筛选与分子鉴定方法,对茅台镇酱香型白酒连续7轮次的大曲和酿造环境样品的可培养细菌进行研究,从样品中共分离得1 370株细菌,归属于5个门、28个属和59种细菌。所分离菌株中Bacillus solani、B.gottheilii、B.paralicheniformis、Brevibacillus agri、Pseudomonas xanthomarina、Lelliottia nimipressuralis、Aureimonas sp.、 Sphingobacterium daejeonense、Oceanobacillus indicireducens、Cronobacter sakazakii、Mixta gaviniae、Paraburkholderiafungorum、Viridibabacillus arvi和Atlantibacter hermannii在酱香型白酒酿造中鲜有检出并报道。细菌的分布频率和优势度分析表明,Bacillus、Lysinibacillus、Staphylococcus和Micrococcus为大曲中的核心可培养细菌,Bacillus、Staphylococcus、Micrococcus和Alcaligenes为环境中的核心可培养细菌,Bacillus、Staphylococcus和Micrococcus为大曲和环境样品中共有的可培养核心细菌。各轮次大曲与环境样品中的细菌菌群多样性结构存在差异,但其主要功能细菌菌群结构及其演替基本保持一致。大曲和环境样品中的优势细菌均可代谢丰富酶系的功能,且具有较强的金属离子吸附降解功能。本研究可为茅台镇酱香白酒酿造及其他地域酱香型白酒酿造微生物的研究提供基础。     

芝麻香型白酒酿造用功能细菌麸曲的优化

对芝麻香型白酒酿造用功能细菌麸曲6株芽孢杆菌产中性蛋白酶发酵培养基进行了优化,最终确定了最佳发酵培养基为:甘油20 g/L、豆粕25 g/L、Na_2HPO_4 4 g/L、K_2HPO_4 0.3 g/L。在此基础上增加一株高产四甲基吡嗪的解淀粉芽孢杆菌104,通过结合选取的6株芽孢杆菌进行固态混合发酵配方组合研究以及不同比例情况下的对比验证,建立起了菌株混合发酵合成蛋白酶和四甲基吡嗪的最佳配比组合。     

浓香型皇台大曲可培养细菌群落结构及其产淀粉酶的研究

采用稀释平板法,从浓香型皇台大曲中分离纯化出73株细菌菌株,经PCR扩增其16S rDNA并测序,比对分析发现这些纯化的细菌菌株中有23株16S rDNA序列各异的可培养细菌,这些菌株分别为Bacillus licheniformis16株、Bacillus subtilis2株、Bacillus amyloliquefaciens1株、Bacillus cereus1株、Bacillus atrophaeus1株、Bacillus sonorensis1株和Brevibacillus sp.1株;采用透明圈法和液态发酵法对大曲中可培养细菌产淀粉酶性能进行检测,结果表明Bacilluslicheniformis、Bacillus subtilis和Bacillus cereus的一些菌株产淀粉酶的活性较高,其中,Bacillus licheniformis的数量最多,是重要的白酒酿造功能菌。     

酒醅及窖泥中乳酸菌的筛选及产酸特性研究

在酿酒过程中,乳酸菌的优劣对酒的质量和风味特征有显著的影响。从馫香型白酒酿造发酵醅及窖泥中通过溴甲酚紫显色法分离纯化出8株产酸菌,经复筛得到一株高产乳酸的菌株L1,鉴定为Weissella confusa;对L1进行产酸发酵特性研究及耐p H值、耐温度、耐渗透压分析,结果表明,在培养2 d时L1菌株进入稳定期,发酵6 d时乳酸产量趋于平稳,当培养基中葡萄糖添加量为20 g/L、pH6.0、菌株接种量为2%、培养温度为35℃时乳酸产量最高,达5.341 g/L。     

酱香型白酒耐乳酸酵母的筛选及特性研究

该研究从酱香型白酒发酵酒醅中筛选一株高乳酸耐受性的酵母菌进行菌种鉴定,并比较该菌株与模式菌株ATCC6258及用于白酒酿造菌株CICC1926对乳酸的耐受特性,并初步分析该菌株在不同乳酸含量条件下挥发性风味物质的代谢特征。结果表明,获得一株高乳酸耐受特性的菌株MT-Y01,通过形态观察及分子生物学鉴定为库德里阿兹威氏毕赤酵母（Pichia kudriavzevii）;与模式菌株ATCC6258及其用于白酒酿造菌株CICC1926相比,菌株MT-Y01对乳酸的耐受性更强,最高可耐受120 g/L的乳酸;该菌株可在0～120 g/L乳酸含量范围内代谢生成多种酱香型白酒中的风味物质,且产酯能力强,是酱香型白酒发酵过程中一株重要的酵母菌。     

功能微生物在酱香大曲白酒生产中的应用

通过分别对不同的细菌和酵母菌株进行混合培养,先后对不同混合菌株进行实验室酒醅发酵实验和入窖生产实验,测定白酒中酒精、总酸、总酯含量等指标,结果表明,混合酵母F1Z3组和混合细菌123组的混合强化菌株与对照组比较,白酒的风格和品质在不同程度上都有所提升。     

清香型酒醅中一株产乙酸乙酯酵母菌的筛选及其应用性能分析

固态白酒发酵过程中,酵母菌对产酒、产酯、生香等都有重要的影响。为提高清香型白酒的品质,以清香型发酵酒醅为筛选源,采用变色圈平板初筛,发酵力复筛,并结合乙酸乙酯生成能力测定、麸曲培养检测、固态发酵产风味代谢物质分析等,研究该筛选出的高产乙酸乙酯酵母菌的应用性能。结果表明,筛选出两株适合清香型白酒酿造的酵母菌菌株;其中,高产乙酸乙酯的菌株jmz-01,其发酵力为0.968%、酯化力为4.694u/L;高发酵力的菌株jmf-01,其发酵力为2.230%、酯化力为1.466u/L。菌株jmz-01的单菌种固态发酵产挥发性风味物质有乙醇、苯乙醇等醇类,乙酸、异戊酸等酸类,并含有多种其他类风味物质,如:苯乙醛、2-十五烷酮、乙酸乙酯等;其强化麸曲的酯化力为65u、糖化力为132u、发酵力为4.30%,表明该菌株在白酒酿造生产中具有较高的应用前景。     

仰韶陶融型白酒大曲可培养微生物多样性研究

研究陶融型白酒大曲可培养微生物的多样性。采用组织培养方法分离陶融型白酒大曲的微生物,提取分离菌株DNA,用酵母通用引物NL1/NL4、细菌通用引物799F/1492R和真菌通用引物ITS1/ITS4对酵母26S rRNA、细菌16S rRNA、霉菌28S rRNA序列扩增,提交测序分析,构建系统发育树。仰韶陶融型白酒大曲酒曲中共分离到酵母213株、细菌386株、霉菌73株,酵母归分为72株形态种,细菌归分为77株形态种,霉菌归分为7株形态种,根据测序结果不同,陶融型白酒大曲微生物被分为21个分类单元。仰韶陶融型白酒大曲可培养微生物具有多样性特征,为其发酵及开发利用提供理论参考。     

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