猕猴桃酒用酵母的选育研究

为选育出猕猴桃酒专用酵母,采用酵母分离和比较发酵的方法,对猕猴桃酒用酵母进行了初步筛选。通过观察菌落特征及镜检细胞形态,筛选出YZ1、YZ2、YZ33株酵母菌。经发酵试验表明,YZ1菌株发酵彻底,产酒精度达9.4%;产酸能力强,达4g/L以上;对SO2的耐受力为30～40mg/L;耐酸性强,发酵醪酸度高,起酵速度快,且发酵酒的香气和风味均优于YZ2和YZ3的发酵酒。因此将YZ1菌株培育驯化后可得到猕猴桃酒专用酵母。     

一种猕猴桃果酒专用酵母的高效筛选方法

为探索猕猴桃果酒专用酵母的筛选方法,提高果酒品质,以雅安红阳猕猴桃为原料,从自然糖度（150 g/L）和添加白砂糖达到高糖度（350 g/L）的两组猕猴桃汁发酵液中筛选酵母,对其发酵性能进行测定,并通过微生物质谱检测对其进行菌种鉴定。结果表明,经一级筛选,各分离出3株菌株,编号分别为ZR-1、ZR-2、ZR-3及GT-1、GT-2、GT-3,其中菌株ZR-1及ZR-3被鉴定为柠檬形克勒克酵母（Kloechera apiculate）,其他菌株均被鉴定为酿酒酵母（Saccharomyces cerevisiae）。菌株GT-2发酵力最持久,产酒精力最强,发酵液中酒精度达9.5%vol,且对150 mg/L的SO2和pH=3.0的酸性环境的耐受性最强;菌株GT-1对12%vol酒精耐受性最强,原酒感官评分最高。说明以高糖启动自然发酵,从中筛选酵母简便且准确度高,可作为猕猴桃果酒专用酵母的高效筛选方法。     

酵母菌株对猕猴桃果酒香气成分的影响

猕猴桃果酒香气与发酵用酵母菌株关系十分密切,本研究从猕猴桃果实的果皮上分离酵母菌株,经过纯化、筛选、鉴定得到适于猕猴桃果酒酿制的酵母菌株,并采用GC-MS分析其对猕猴桃果酒香气组成和含量的影响。结果表明:筛选得到的2株酵母菌1-21和1-31经26S r DNA鉴定分别为酿酒酵母和东方伊萨酵母,与商业酿酒酵母相比,1-21具有发酵力强、耐酸性强和果酒中抗坏血酸含量高等特性,1-31具有耐高浓度SO2特性和果酒香气独特的特性。通过比较,不同酵母菌株所酿制猕猴桃果酒的香气成分在组成和含量上存在特异性差异,49种检出组份中有13种是相同的香气成分,8种为1-21菌株所酿猕猴桃果酒所独有,7种为1-31菌株所酿猕猴桃果酒所独有。此外,筛选菌株酿制的猕猴桃果酒香气组份含量明显高于商业菌株,因此认为筛选菌株能更好的表达猕猴桃果酒的特征香气。     

一株高产酒精酵母菌的筛选及特性研究

为了获得高产酒能力的功能特性酵母菌株,对白酒车间样品中分离出的数百株酵母菌株进行定性筛选,经发酵糖产气法初筛和发酵能力复筛,最终获得3株产酒精能力强的酵母菌.通过形态结构观察和生理特征分类鉴定,初步判断Q1XX-64Y和Q1XX-80Y属于酿酒酵母属,CW-65Y属于酒香酵母属.对筛选出的3株酵对菌进行产酒率及发酵产香成分的测定,结果表明,CW-65Y菌株利用糖固化碳源,发酵力和淀粉出酒率最高,分别为18.04g/100g和29.61%,是适合用于白酒强化发酵的优良酵母菌株.     

昌黎赤霞珠葡萄相关酿酒酵母的分离与筛选

以昌黎地区赤霞珠葡萄为样本,从中分离出5种酵母。通过菌落特征、菌体形态及赖氨酸培养基鉴定,初步确定其中4株为葡萄酒酿酒酵母。通过高浓度酒精(10%~18%)、高浓度SO2(100~400mg/L),高糖浓度(10%~60%)和高温(37、42℃)的耐受性实验,初步筛选出两株可耐受14%浓度酒精、300mg/L SO2、50%的葡萄糖浓度及42℃高温的菌株。与市售的两种酿酒酵母进行葡萄酒发酵实验,将所得酒样进行理化分析及感官品评,结果表明菌株a发酵力强,较市售酵母菌发酵后挥发酸含量低,残还原糖含量为0.40g/L,且葡萄酒感官评价最高。最终选出菌株a为赤霞珠葡萄酿酒酵母最佳菌株。     

酿酒酵母发酵性能的比较

以从民间自制黄酒酒药、酒厂的酒曲和窖泥中分离筛选得到的4株酵母(1#、2#、3#、4#为出发菌株,对其进行耐受酒精能力、耐受酸能力、发酵速率及发酵液中尿素含量、残糖、酒精度、总酸及氨基酸态氮等生理性能综合比较,其结果显示为4#酵母较其他3株发酵力强,耐受酒精浓度为14％vol,耐酸浓度为2.5％,产尿素含量为37.23mg/L,且其产尿素含量比2#酵母少56.7％,残糖浓度为12.57g/L,产酒精度达到16.1％vol,总酸含量为2.99g/L,氨基酸态氮含量为0.48g/L,具有进一步开发利用的价值.     

传统面食发酵剂中酵母菌的筛选及性能研究

对山西地区传统面食发酵剂中酵母菌进行筛选分离及初步鉴定,考察酵母的发酵力、耐酒精能力、耐酸性及抗冻性等指标。结果表明:两株酵母菌分别为萨地假丝酵母(编号Q3505)和卡斯特酒香酵母(编号Q5503)。其中菌株Q5503发酵3 h面团体积可达410 m L,产气490 m L。菌株Q3505发酵3 h面团体积可达395m L,产气270 m L。在耐酸性和耐酒精能力上,菌株Q5503优于Q3505;在抗冻性方面,冷冻60 d后的菌株Q5503和Q3505发酵力保持率分别为83.33%和64.39%,表现出较好的抗冷冻性,具有一定的工业应用前景。     

本土低产硫化氢酵母的分离、鉴定和酿造性能评价

文章以四川本土采集的3种葡萄自然发酵液为分离源，经分离、纯化和筛选后得到5株具有优质发酵潜质的低产H2S葡萄酒酵母菌。利用WL培养基对筛选的酵母菌进行分类鉴定，结合26S r DNA测序鉴定并构建系统发育树，确定其中3株为Saccharomy cescerevisiae(H4、Q28、Z31),2株为Hanseniaspora opuntiae(Q8、Z17)。以1株法国LAFFORT(F15)商业葡萄酒酵母为参照，研究分离酿酒酵母的酿造特性。结果显示，Q28发酵组葡萄酒酒体香气协调、饱满，模拟发酵性能与商业酵母F15无显著差异(P>0.05);Z31、Z17菌株发酵的葡萄酒中GSH含量为37.24、38.86 mg/L，与商业酵母F15(37.99 mg/L)无显著差异。综合比较理化指标和感官分析结果，Q28具有更高的发酵力，所发酵葡萄酒感官品质优良，具有成为商业酵母的潜在能力。     

野生猕猴桃酿酒酵母的筛选及其发酵特性

以大别山野生猕猴桃为原料,经由猕猴桃汁初筛,YEPD培养基复筛获得酵母菌株。通过WL培养基观测形态,采用杜氏管发酵法、猕猴桃果汁发酵法等进行发酵能力评估,并进行了耐受性研究,然后对其酿酒特性进行测定,通过监测猕猴桃酒的发酵情况变化、测定酒液的酒精度、总酸以及澄清度、香味、口感等感官指标,筛选出最佳酿酒酵母。结果表明:M5菌株发酵活力强,可耐受14%vol的酒精度、300 g/L的糖和300 mg/L SO₂,发酵周期短、酒液清澈、酸度为0.8 g/100 mL,酒精度可达9.8%Vol,V_C含量可达40.8 mg/100 mL,感官品质在五株菌中最佳,有望驯化为酿造猕猴桃酒的优良酵母。     

果胶甲酯酶抑制剂的异源表达及其在果酒降甲醇中的应用

该文从猕猴桃中克隆出果胶甲酯酶抑制剂（Pectin Methylesterase Inhibitor,PMEI）基因,经EcoRⅠ/XbaI双酶切后连接到表达载体pPICzαA上,电转化到毕赤酵母GS115筛选出阳性菌株GS115/pPICzαA-PMEI,并将重组酵母表达的PMEI浓缩纯化后应用于果酒发酵。研究结果表明：重组毕赤酵母表达菌株GS115/pPICzαA-PMEI成功构建,PMEI的发酵表达量为35.38 mg/L。将PMEI应用到果酒发酵中,桔子酒甲醇降低47.54%,含量由189.75 mg/L降低到99.55 mg/L;苹果酒甲醇降低21.52%,含量由118.15 mg/L降低到91.20 mg/L;葡萄酒甲醇变化不显著,含量均低于20.00 mg/L,表明PMEI对果胶丰富且内源性果胶酶强的桔子具有明显的降甲醇效果。桔子酒发酵工艺优化的PMEI最低抑制质量浓度8.84 mg/L,最适温度18 ℃,此时桔子酒中的甲醇降低66.40%到89.10 mg/L。这为低甲醇果酒的发酵提供了新的技术路线。     

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