金种子优质窖泥高产己酸菌的筛选鉴定及其应用性能分析

在浓香型白酒酿造过程中,窖泥作为酿酒微生物的重要载体对曲酒的酒体质量与风格特征具有重要影响。从优质窖泥中筛选高产己酸菌,并制备人工窖泥以提高酒体中己酸乙酯的含量或制备生产己酸乙酯产品等,对曲酒生产具有重要意义。本文通过富集培养、平板涂布、发酵液己酸含量检测、16S rDNA分析等方法,筛选鉴定高产己酸菌株,并考察培养温度、乙醇浓度、pH值等发酵条件,分析己酸菌液配方组分单因素含量影响等。结果表明,筛选得到的高产己酸菌JZZ,其液态发酵己酸平均产量为4.36 mg/mL,温度耐受区间为36~39℃,乙醇耐受浓度为2%~6%,己酸菌液配方组分添加量为硫酸镁0.01%,硫酸铵0.05%,磷酸氢二钾0.3%,乙醇2%,16S r DNA比对结果表明,JZZ菌株为克氏梭状杆菌(Clostridium kluyveri)。     

无窖泥发酵生产浓香型白酒

浓香型白酒是我国产销量最大的白酒,传统的泥窖发酵劳动强度大、机械化操作困难,且原酒常常带有窖泥臭味。该研究采用窖泥微生物(己酸菌群)单独培养制备己酸发酵液,再与大曲微生物发酵酒醅(前发酵)混合发酵,实现无窖泥发酵生产浓香型白酒。己酸发酵液的制备采用液态厌氧培养,通过考察发酵产酸情况确定发酵时间为9 d,此时己酸含量达到10 g/L左右,丁酸含量达到2 g/L左右;前发酵为传统的固态发酵,由乙醇体积分数、残淀粉等发酵理化指标确定发酵周期为6～8 d;己酸发酵液与前发酵酒醅混合进行后发酵,己酸发酵液添加量为0. 40 g/kg,总发酵周期为42 d。在此条件下,酒醅四大酯含量较高,比例协调,该研究为无窖泥发酵生产浓香型白酒打下基础。     

己酸菌的筛选及发酵特性研究

在浓香型白酒生产中,己酸菌是窖泥中的重要功能菌,影响着白酒的品质。本研究通过对老窖泥进行富集培养,分离筛选出1株高产己酸的己酸菌,经16S rDNA鉴定为速生梭菌(Clostridium celerecrescens),命名为E-6。并研究培养时间、培养温度、乙醇添加量对菌株的生长和发酵特性的影响。结果表明,E-6产己酸的最佳培养温度为34℃,乙醇添加量为2 mL/100 mL,此条件下培养10 d左右己酸产量可达到9.4 g/L。     

生香酵母在液体窖泥中的应用

在浓香型白酒生产中,窖泥中己酸菌数量的多少及其质量的优劣直接影响酒质。研究生香酵母与己酸菌复合培养制作的复合液体窖泥应用于浓香窖池养护,试验结果表明,生香酵母与己酸菌的复合培养,可进一步提高液体窖泥中己酸菌数量及代谢产物,有利于浓香型白酒生产中窖池的养护效果,对提高浓香型白酒的产量和优质酒率有促进作用。     

己酸菌、窖泥与浓香型白酒之间的关系

己酸菌和窖泥与浓香型白酒关系密切,在一定程度上说,是它们在决定着浓香型白酒的质量及风格。就己酸菌与窖泥、己酸菌与甲烷菌、窖泥与清香、浓香、凤香等白酒之间的关系作了详细阐述,分析了浓香型白酒生产中窖泥退化的原因及防治措施,并就人工窖泥培养的配方、原料选择、工艺操作及管理等方面作了介绍。     

己酸菌的选育、培养和应用研究

0 前言 浓香型白酒在生产中素有“百年老窖出好酒”之说,为揭示“百年老窖”出佳酿的奥秘,自六十年代开始,我国开展了浓香型酒与窖泥微生物的关系研究,发现老窖中栖息的己酸菌就是老窖发酵生香的一种主要功能菌。     

浓香型白酒窖泥营养液配方正交设计优化

窖泥营养液是浓香型白酒生产的主要物料之一,在窖泥制备和养护中发挥重要作用。为提高营养液的制备质量,本研究以己酸菌JZZ和窖泥复合菌液为菌种,以营养液中己酸含量为指标,采用正交设计优化窖泥营养液的配方。结果表明:添加不同浓度的乙醇、醋酸钠、磷酸氢二钾、硫酸镁条件下,营养液中己酸含量不同,单因素对营养液质量有影响;正交试验分析提示各因素对营养液的影响程度依次为:乙醇浓度醋酸钠浓度磷酸氢二钾浓度硫酸镁浓度;最佳培养配方为:酵母膏0.1%,硫酸铵0.05%,乙醇2%,磷酸氢二钾0.15%,硫酸镁0.005%,醋酸钠0.25%,在此配方下培养,己酸含量达到4.31mg/mL本研究采用正交设计获得了最佳窖泥营养液。配方,营养液中己酸含量高,为窖泥营养液的进一步应用奠定基础。     

己酸菌发酵液在浓香型大曲酒生产中的应用

己酸菌是梭状芽孢杆菌的一种,是浓香型大曲白酒发酵中起决定作用的一种窖泥功能菌,它的数量多少和功能的强弱直接影响浓香型大曲酒发酵的质量。本实验利用己酸菌液淋窖、灌窖及其养护窖,使用前后对照分析己酸菌发酵液对浓香型大曲酒的影响。     

己酸菌选育及在浓香型白酒生产中的应用

己酸是浓香型白酒的主体风味物质己酸乙酯的合成前体,己酸菌是己酸合成的主要功能微生物。优良己酸菌经扩大培养后制作成窖泥培养菌剂对改善窖泥质量、提升浓香型白酒品质大有裨益。该文综述了近年来有关己酸菌筛选情况,重点论述了己酸合成的途径和改进策略,并介绍了己酸菌在浓香型白酒生产中的应用,以提高白酒品质。     

关于甲烷菌与己酸菌发酵调节发酵温度加快新窖老熟的探讨

大曲酒是开放式生产，自然条件对生产过程造成的影响很大。通过研究发现甲烷菌与己酸菌共生发酵开辟了新的发酵途径，可促进发酵速度按理想的温度缓慢进行。此外，还发现甲烷菌与己酸菌培养发酵窖泥可以加速新窖老熟，提高浓香型酒质量和出酒率。     

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