啤酒连续发酵风味形成的研究进展

啤酒连续发酵系统的前景主要是麦汁向啤酒的转化加速。数十年来,啤酒连续发酵作为前景技术被研究,而工业应用仍然有限。该技术广泛应用的主要壁垒是在连续系统中短时间内达到感官风味平衡存在困难。本文全面综述了连续系统的特点,这些特点可能使连续发酵啤酒的感官明显区别于传统发酵啤酒。通过过程参数和菌株筛选,从可能的调控措施观点讨论主要风味活性化合物。     

睥酒连续发酵风味形成的研究进展

啤酒连续发酵系统的前景主要是麦汁向啤酒的转化加速.数十年来,啤酒连续发酵作为前景技术被研究,而工业应用仍然有限.该技术广泛应用的主要壁垒是在连续系统中短时间内达到感官风味平衡存在困难.本文全面综述了连续系统的特点,这些特点可能使连续发酵啤酒的感官明显区别于传统发酵啤酒.通过过程参数和茵株筛选,从可能的调控措施观点讨论主要风味活性化合物.     

微胶囊技术在啤酒生产中的应用研究

介绍了微胶囊固定化啤酒酵母细胞的原理以及研究了影响微胶囊稳定性的几个关键因素,阐述了微胶囊技术在啤酒连续生产应用中的可行性,结果表明连续发酵生产的啤酒与分批发酵相比,风味、口感都比较接近.     

流态化微胶囊固定酵母技术在啤酒生产中的应用研究

采用微胶囊包埋法固定酵母细胞,同时利用流态化技术,使胶囊化的酵母细胞悬浮于稳定状态的发酵液中。通过控制流量、温度和压力,连续进行麦汁的二级主发酵,然后不断取走嫩啤酒,从而实现啤酒的连续化生产。结果表明连续发酵生产的啤酒与分批发酵相比,风味、口感都比较接近。     

啤酒连续发酵中酵母生理状态的初步研究

研究了长时间的啤酒连续发酵过程中酵母生理状态的变化情况。结果发现 ,酵母凝聚性先上升后逐渐回复至起始值。酵母的发酵性能、死亡率基本不变。A、B类氨基酸在麦汁中浓度越大 ,在同样降糖率的连续和分批主酵液中的含量差别越小 ;C组氨基酸在麦汁中的浓度越大 ,在连续和分批主酵液中的含量差别也越大。连续和分批主酵液的高级醇含量基本相同 ,乙酸乙酯含量的差异是连续发酵和分批发酵生产的 2种啤酒风味差异的主要原因。     

啤酒连续发酵的现状和发展

介绍了连续发酵的两种方式：固定化酵母连续发酵和游离酵母连续发酵，分析比较了它们的优缺点，并介绍了这两种方式在啤酒生产中的应用现状和发展前景。     

酒花收获日期对使用干酒花的啤酒中酒花香气的影响

本文的研究目的是考察酒花收获时间对使用干酒花lager啤酒风味的影响。选择的收获日期定为24天,从收获早期（date 1）到晚期（date 5）。为了评估啤酒的风味稳定性,选择date 2和date 5酒花酿造的啤酒进行品评。本项研究的第一步是考察干酒花收获日期是否会对千酒花啤酒的风味稳定性产生影响,结果表明晚收获的酒花酿造的啤酒风味稳定性稍好些。然而,随着储存时间和温度的增加,储存45天后的差异减小并趋于稳定;总体啤酒风味变化很大;啤酒的香气分值减小。在低于28℃储存时,晚收获酒花酿造的啤酒香气分值仅稍高于早收获酒花酿造的啤酒,只有低温储存条件下,date 5酒花酿造啤酒的苦味质量才会稍微高些。因此晚收获的酒花有利于啤酒的风味稳定性,但是作用时间是有限的,低温储存啤酒时晚收获酒花对风味稳定性的贡献非常显著。     

啤酒连续发酵新工艺

由上海啤酒厂、上海市工业微生物研究所、上海市轻工业设计院组成的三结合小组于一九七五年在上海啤酒厂进行了啤酒连续发酵新工艺的试验工作,经过60升/天实验室规模,5吨/天啤酒连续发酵中间试验,已初步取得一些成果,目前,啤酒连续发酵中型试验还在进行之中。     

固定化多菌种发酵海藻酒的研究

采用PVA固定化酿酒酵母和产香酵母发酵海带，酿造海藻酒。对游离细胞与固定化细胞的分批发酵和连续发酵的动力学进行了研究并建立了相应的发酵动力学方程。实验结果表明：酿酒酵母和产香酵母最佳配比为4：1，发酵温度20℃，固定化细胞分批发酵和连续发酵凝胶粒的充填系数分别为0．25和0．5，游离混合细胞的发酵时间为7d，固定化细胞连续发酵稀释速率0．12/h，发酵时间为0．5d左右。经160d连续发酵实验，PVA固定化细胞粒子的机械强度良好。     

啤酒风味稳定性的化学评定

啤酒风味稳定性的化学评定前言对酿造师来说，罐装啤酒的货架寿命一直是一个特别重要的问题。在贮存时间，啤酒质量逐渐下降，出现变味、浑浊、颜色加深等现象。特别是包装后贮存期间的啤酒变味问题很长时间一直困扰着酿造师。啤酒风味酸败通常是通过感觉分析来评定。然而...     

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