提高啤酒非生物稳定性的措施

1。选用蛋白质含量低的大麦和新鲜酒花。2．适当增加大米用量。3．煮沸强度要大，控制PHS．2左右，但煮沸时间不能过长。4．在发酵过程中，对麦汁充Q。5．啤酒风味成熟后，向贮酒罐中添加适量单宁，以促进蛋白质与单宁结合，然后通过过滤除去。6添加聚乙烯聚吧咯烧酮等吸附剂，以吸附啤酒中的单宁成分。7．在滤酒、灌酒前采取措施防止氧溶入。如滤酒时用除氧水和硅藻土，充分搅拌，尽可能排除空气，灌酒时用水充满管道与灌酒机的酒槽，排除空气。8．在低温、避光处保存啤酒。提高啤酒非生物稳定性的措施@苗敬芝$江苏徐州市彭城职业大学!22…     

低压煮沸工艺降低麦汁中可凝固氮含量

采用低压煮沸工艺，可提高煮沸麦汁温度至100．5℃，加强蛋白质凝聚，麦汁可凝固氮下降0．5mg／100mL；煮沸过程加强了美拉德反应、“棕色反应”，类黑精、类黑素化合物增加，麦汁色度增加，麦汁的抗氧化能力增强；煮沸强度从9％～12％降至7％～8％，煮沸时间缩短10～20min，提高生产效率，节约能源20％；改善啤酒非生物稳定性。（孙悟）     

缩短煮沸时间对啤酒质量的影响

众所周知，麦汁煮沸是啤酒酿造过程中的一个重要环节。在原有设备和煮沸强度不变的基础上，验证缩短煮沸时间对啤酒非生物稳定性和风味的影响。     

麦汁煮沸工艺对凝固氮含量的影响

延长煮沸时间和增加煮沸温度可降低麦芽汁凝固氮含量，但会增加麦汁色度；单宁的理想添加浓度为60mg／kg；添加复合硅胶可吸附沉淀部分蛋白质颗粒，降低啤酒色度，提高啤酒非生物稳定性。     

麦汁煮沸时影响蛋白质凝聚的因素

麦汁煮沸的目的之一，是尽可能将麦汁中可凝固蛋白南凝聚并分离出来，以改善啤酒风味和非生物稳定性。文章从麦汁组成、煮沸强度、煮沸时间、煮沸方式，麦汁ｐＨ及酒花添加等方面分析了麦汁煮沸时影响蛋白质凝聚的因素。     

瓶装啤酒巴氏灭菌泡沫环成因及预防

啤酒泡沫环主要成分为高分子肽、多酚物质、碳水化合物、金属离子等。形成因素有：原料麦芽质量、酒花、酿造用水含Fe^2 高；麦汁的煮沸强度、煮沸时的pH值；发酵工艺等。预防措施有：选择优良的原辅料；工艺选择及工艺过程中的参数控制。（孙悟）     

影响酒花α-酸异构化的因素

α-酸是啤酒酒花的主要成分，也是啤酒苦味的主要物质，啤酒中的α-酸异构物可提高啤酒的泡沫稳定性。提高啤酒质量。影响α-酸异构化的因素有：煮沸时间、煮沸方法、煮沸温度、煮沸压力、酒花添加量及酒花品种、煮沸时含氧量、煮沸pH值、麦汁浊度和添加的辅料物质。(孙悟)     

Vb-Na在啤酒酿造中的应用--取代甲醛、偶合双乙酰、抗氧化

生物和非生物沉淀均严重影响啤酒的质量。提高啤酒非生物稳定性可通过控制大麦质量、制麦工艺、糖化工艺、煮沸工艺得以改善；实现生产场地、工具等的有效灭菌，可提高非生物稳定性。Vb-Na新型天然抗氧化保鲜稳定剂可有效除去啤酒中的溶解氧和啤酒中的金属离子，防止啤酒中多酚类物质的氧化聚合，消除金属离子催化作用。阻止双乙酰回升，提高啤酒非生物稳定性、啤酒风味质量，延长啤酒保质期。     

论啤酒中二甲基硫

控制啤酒中二甲基硫的措施：①控制大麦浸度，缩短发芽时间，延长凋萎时间。②大麦发芽时添加溴酸钾。③高温长时间焙焦。④采用煮出糖化法较浸出糖化法DMS含量低。但对色泽、口味不利。⑤提高煮沸强度，延长煮沸时间。⑥缩短热麦汁在沉淀槽中停留时间。⑦提高发酵温度。⑧运输、贮存、销售过程避光照射。⑨搞好工艺卫生，防止腐败微生物污染。⑩选用蛋白质含量适中，收获时间短的大麦。     

影响麦汁煮沸强度的主要因素

<正>煮沸强度是麦汁煮沸过程的重要技术参数,其含义为麦汁煮沸时,每小时蒸发出的水分相当于混合麦汁的百分数。麦汁煮沸强度直接影响麦汁组分、浓度、色度及可凝固氮的含量。合理控制煮沸强度对啤酒的非生物稳定性及口感具有重要意义。本文将结合煮沸强度公式煮沸强度=[混合麦汁量(L)-最终麦汁量(L)]/[混合麦汁量(L)×煮沸时间(h)]×100%,以及生产实际对影响煮沸强度的各种因素进行     

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.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.