苹果酒中高级醇生成的研究

通过单因子试验及正交试验,研究苹果酒酿造过程中苹果汁初始pH值、发酵温度、酵母接种量、加(NH4)2H PO4量等不同因素对高级醇生成的影响。研究发现,外加氮源、较低的pH及发酵温度对高级醇的生成都有很好的抑制作用,确定在实验条件下,高级醇生成量最低的酿造工艺:发酵温度20℃、酵母接种量为0.10%、加(NH4)2H PO4量为200m g/kg、苹果汁初始pH值为3.3。     

苹果酒酿造工艺及高级醇的气相色谱分析

以富士苹果为原料,利用安琪葡萄酒活性干酵母、丹宝利高活性干酵母和Y1酵母(本实验室自选)分别在18、23、28℃3种条件下进行苹果酒发酵试验,主发酵结束后用气相色谱测定高级醇含量并对苹果酒的质量进行感官评定。试验结果表明:利用安琪葡萄酒高活性干酵母,在23℃条件下发酵酿造的苹果酒感官评定分数最高;以安琪葡萄酒高活性干酵母和丹宝利酵母为菌种发酵时,高级醇的含量随着发酵温度的增加逐渐增加,而Y1酵母在低温条件下发酵时高级醇含量较高;苹果酒中异丁醇等高级醇含量(X)和感官评定分数(Y)呈线性相关,其回归方程为y=-6×10-5x+92.4,相关系数r=0.7846(p<0.01);苹果酒中异丁醇等高级醇以在发酵过程中形成为主。     

青梅果酒酵母的筛选与发酵工艺优化

选取11株耐受性较好的果酒酵母对青梅果酒进行发酵试验,以酒精度、总酸和感官指标为考察参数,筛选出1株发酵能力强,所酿造果酒品质好的为最优菌株。通过研究果实成熟度、酵母添加量、主发酵温度对青梅果酒品质的影响,确定青梅果酒的最佳酿造工艺参数。优化后的青梅果酒发酵工艺条件为:青梅果实成熟度为8~9成;酵母接种量为0.3 g/L;主发酵温度为20℃。在此条件下进行3.5 t发酵罐的生产试验,发酵过程稳定,所得的青梅果酒酒精度为13.9%vol±0.3%vol,残糖量为0.97 g/L±0.21 g/L,总酸含量为37.42 g/L±1.48 g/L,干浸出物含量为51.36 g/L±1.24 g/L。     

酵母对苹果酒酿造品质影响的研究

苹果经榨汁澄清后,分别接种七种果酒酵母,20℃恒温发酵。发酵结束后,对苹果酒进行理化分析和感官评价,评定七种酵母的酿造特征,并观察外加氮源和不同量SO2对酵母及苹果酒理化指标的影响。实验结果表明:在相同试验条件下,7号酵母起酵最慢,4号发酵最快,6号发酵最旺盛。加硫组,整体起酵慢。各种酵母酿造苹果酒的理化指标有所不同,酒的香气、口味和风格也不同。氮源和SO2对七种酵母发酵苹果酒的理化指标影响不显著。     

苹果酒发酵中酵母菌株的筛选

酵母菌的性能是决定果酒品质的关键因素之一，本实验以苹果酒为研究对象，采用安琪酵母公司研发中心菌种保藏室收藏的10株果酒酵母（3#～11#，522#）为备选菌株，在干型苹果酒生产发酵工艺的指导下，通过系统的对比实验和结果评价，确定出9#酵母菌最适合苹果酒的酿造。     

低高级醇石榴酒的酵母筛选及发酵工艺优化

为了探究酵母种类和发酵条件对石榴酒高级醇含量的影响,本实验以石榴汁为原料,通过全汁发酵的方法,采用两种不同的工艺对酿酒酵母进行筛选以及对酿造条件进行优化,生产高级醇含量低的石榴酒.通过对石榴酒理化性质的测定以高级醇含量作为主要指标筛选出最佳酵母和最优条件,结果显示:筛选的酵母中,WY-T21酵母生成的高级醇含量最低,总...     

低醇苹果酒的研制

以国光苹果为原料,采用带渣发酵,通过控制糖的添加量来保证苹果酒的酒精含量为5%vol。利用正交试验确定低醇苹果酒的最佳工艺条件为：酵母接种量为0.3%,初始pH为3.5,发酵温度为18℃。通过单因素试验对半甜型苹果酒中酸度和糖度进行确定,最终得到营养丰富、具有多种保健功能的低醇苹果酒。     

胡柚果酒酿造工艺优化

以新鲜胡柚为原料酿造胡柚果酒,从酒精度、脱苦率等方面对酿造工艺进行分析。通过单因素和响应面试验优化酿造工艺条件。结果表明,胡柚果酒的最佳酿造工艺条件为柚苷酶添加量80 mg/L、发酵温度25 ℃、酵母接种量7%、SO2添加量40 mg/L。该最佳工艺条件下酿造的胡柚果酒果香浓郁、醇和爽口、苦味适中,脱苦率达46.63%,酒精度为13.7%vol。     

家用果酒酿酒器的设计及果酒发酵工艺

针对目前市场上家用酿酒器及果酒酿造工艺的不完善。通过选育高效果酒发酵酵母菌、控制等技术,设计一款低功率、操作简单的家用型果酒酿酒器,并选育出一株高效性酵母菌。家用果酒酿酒器主要由温度控制、搅拌等系统组成。通过优化酵母选育工艺并对比市面上销售的发酵酵母的发酵性能,说明了自主筛选酵母在高糖条件下的发酵优越性。通过试验验证设备及酿酒工艺的稳定性,并将果酒酿酒周期缩短至7 d。该装置及工艺弥补了国内外家用果酒酿酒的不足,具有显著效益。     

响应面法优化沙枣果酒发酵工艺的研究

沙枣含糖量为43%~52%,富含多种营养物质,可以作为原料酿造保健型果酒;为了充分地利用沙枣资源,优化其加工工艺参数,以沙枣汁为原料,在初糖浓度、酵母接种量、发酵温度和初始pH 4个单因素试验基础上,应用Design-Expert V 8.0.6软件中Box-Behnken试验设计建立回归模型,对沙枣果酒的发酵工艺条件进行响应面分析优化,结果表明:沙枣果酒发酵的最佳工艺条件为:初糖浓度为24%、酵母接种量0.28%、发酵温度为27.78℃、初始pH4.37。此优化条件下,沙枣果酒酒精度达到14.37%vol,果香和酒香协调,风味独特,绵延柔和。     

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