酿酒活性干酵母生理特性的研究

建立一种酿酒活性干酵母生理活性的简易评价方法,比较并筛选一株适合以木薯粉水解液发酵发酵生产燃料酒精的活性干酵母。优化2株酿酒活性干酵母的活化条件、生长温度和生长pH值,以木薯粉水解液为发酵液,在最适生长条件下比较两株酵母的生长曲线、发酵强度、耐糖能力、耐温能力和耐酒精能力。选择酿酒活性干酵母Ⅰ作为木薯粉水解液发酵酵母,该酵母在前36h发酵强度高于1g(/L.h),36h后发酵强度迅速下降;耐糖能力为20%,耐受温度是55℃以及耐酒精浓度是7%。     

酵母活化对酵母产气特性的影响

本研究以安琪低糖鲜酵母和高糖干酵母为研究对象,以酵母产气为评价指标,综合评价不同活化条件对酵母产气特性的影响,结果表明28℃的活化温度为最佳活化温度;不同活化时间对高糖干酵母影响显著,活化40min的样品产气速率和产气量有显著提高;对低糖鲜酵母而言,不同活化时间样品之间的酵母产气量和产气速率都无显著差异,综合考虑40min活化时间的样品效果最好;添加3%的蔗糖活化能够显著提高安琪低糖鲜酵母的产气能力;添加3-5%的蔗糖活化能够显著提高安琪高糖干酵母的产气能力。     

活性干酵母扩大培养的研究

酵母的生长繁殖与其培养的温度和通风量有着密切的关系，以活性干酵母为出发菌体进行了以下试验。1、活性干酵母的活化；2、培养温度对酵母生长繁殖的影响；3、通气量对酵母细胞生长的影响。     

活性干酵母活化时间与级数对葡萄酒发酵的影响

研究活性干酵母活化方式对葡萄酒发酵的影响。 分别将活性干酵母进行不同时间（25 min、3 h 15 min、24 h 15 min）和不同级 数（两级和三级）的活化,将等量的酵母种子活化液接种到24 °Bx模拟葡萄汁中,24 ℃条件下发酵18 d。 结果表明,活化3 h 15 min的酿 酒酵母生长代谢能力强,在葡萄汁中生长繁殖迅速,耗糖快;产乙醇较多（60.88 g/L）;产乙酸较少（0.77 g/L）。 进行三级3 h 15 min活化 的酵母活性高,活酵母菌浓度较大（最高4.53×107 个/mL）,不同级数活化的酵母在发酵过程中还原糖含量差异显著（P＜0.05）,CO2生 成量、乙醇和乙酸含量无显著差别（P＞0.05）。     

红火龙果带皮发酵干红生产工艺研究

以红皮红肉的火龙果为原料，通过不同酵母对其进行发酵实验，筛选出合适的酵母，对筛选出酵母的发酵条件进行优化实验，并对实验结果进行极差、方差分析。结果表明：葡萄酒活性干酵母适合火龙果干红发酵；最佳发酵工艺条件为：发酵温度为30℃，pH4.3，发酵时间为5d。     

耐高温酒精活性干酵母在玉米酒精生产中的应用

在玉米酒精生产中,利用耐高温酒精活性干酵母进行酒精发酵实验,确定发酵温度、发酵液初始pH、酵母添加量、发酵时间对酒精发酵的影响,然后进行正交实验,确定最佳工艺条件为发酵温度37℃,发酵液初始pH为5.0,酵母添加量为1.2‰,发酵时间48h。发酵残液中酒精浓度9.96%。     

不同接种方式及温度对活性干酵母发酵的影响

活性干酵母目前被广泛应用于葡萄酒工业生产中,接入发酵性能良好的活性干酵母进行酒精发酵,能够保证葡萄酒的稳定性,提高葡萄酒的质量。然而,接入的活性干酵母在不同工艺条件下能否在发酵的各阶段占据主导地位仍需验证。本试验以活性干酵母CEC01为研究对象,采用复水活化和干粉直投的方式,并结合低温和回温的接种温度对北冰红葡萄汁进行发酵,研究不同接种条件下CEC01的发酵性能,以及发酵过程中酿酒酵母和非酵母属酵母种类及数量的动态变化。结果表明,复水活化接种启酵和发酵速度快于直投接种发酵,而直投接种处理的发酵过程更加平稳。低温接种发酵中的非酵母属酵母的数量较多。Interdelta指纹图谱分析表明,发酵各阶段CEC01均具有较高的定殖能力(目标菌株比例90%),在酒精发酵中占据主导地位。     

富硒酵母的培养和硒核酸提取的研究

目的:通过对市售活性干酵母耐硒能力的筛选、发酵条件的优化和硒核酸提取方法的研究,得到可供酵母硒核酸生产的菌株。方法:采用摇瓶法培养,运用方差分析法处理正交实验数据。结果:市售活性干酵母普遍具有耐硒富硒的能力。安琪活性干酵母最适宜的摇瓶发酵条件是:无机硒添加量8mg/L,pH5.5,温度30℃,培养时间42h。培养基配方为:葡萄糖20g/L,甘氨酸10g/L,KH2PO40.5g/L,酵母浸膏4g/L,甘油0.4g/L。高浓度的硒对活性干酵母的生长、合成生物量及硒转化能力都有抑制作用。方差分析表明:15%酵母、1.0%NaOH、2.0%CaCl2和60min搅拌时间是提取酵母硒核酸的适宜条件。结论:安琪活性干酵母可作为生产硒核酸的菌株,其提取的硒核酸中硒的含量为4257μg/g干重。     

高活性面包干酵母复水活化温度对酵母活力损失的影响

高活性面包干酵母复水活化的好坏直接影响酵母活性.通过对不同复水活化温度对酵母活力的影响比较研究,得出43℃为干酵母的最佳复水温度.随着温度的进一步升高或降低,活性干酵母的活性损失都有不同程度的增大.     

不同干酵母对甘蔗汁酿酒特性的影响

为研究不同酵母对甘蔗果酒的发酵影响,以新鲜的甘蔗压榨汁为原料,常温下选用葡萄酒高活性干酵母、耐高温高活性干酵母和发利干酵母三种商业活性干酵母进行液态发酵酿制甘蔗果酒。研究探讨了三种酵母菌的生长曲线、凝聚性、发酵度、发酵力、酸化力和产酒精能力等酿酒发酵特性。结果表明,三种酵母菌作用甘蔗汁的发酵过程中,酵母菌生长曲线趋势基本一致,三种酵母菌的凝聚值F<20%,均为非凝聚性酵母。三种酵母菌的发酵力基本相当的,最终产酒精的能力差距不大,其中葡萄酒高活性干酵母最终产酒精为12.2% vol,耐高温高活性干酵母和发利干酵母均为12.0% vol。从三种商用酵母菌对甘蔗汁酿酒的各发酵特性来看,葡萄酒高活性干酵母略优于耐高温高活性干酵母和发利干酵母。研究结果为甘蔗汁发酵酿制风味甘蔗果酒提供了技术参考。     

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