酒精醋发酵条件的研究

以醋酸菌为发酵菌株,食品级酒精为原料,考察了装液量、接种量、初始底酸量和初始酒精度四个因素对醋酸发酵最终的产酸量的影响,利用正交试验、极差分析法和方差分析,确定了酒精醋发酵最佳条件为装液量100mL/500mL、接种量10%、初始底酸量1%、初始酒精度5%。同时考察了醋酸发酵过程中酸度的变化情况,发现在醋酸发酵的开始阶段初始酒精度、初始底酸量对其影响较大,而在发酵后期,接种量影响较大。     

苹果醋饮料生产工艺的研究

以新鲜苹果汁为原料,通过正交试验研究了发酵温度、接种量、起始糖度、时间对酒精发酵的影响以及初始酒精度、接种量、装液量对醋酸发酵的影响。结果表明:酒精发酵的最佳条件为:发酵温度27℃、糖度20%、接种量8%。醋酸发酵过程中,以酒精转酸率和酒精转化率为考查指标时的最佳发酵条件为:初始酒精度15%(体积分数)、接种量20%、装液量65 mL/100 mL三角瓶、发酵温度30℃。     

枣醋醋酸发酵工艺优化

文章在前人研究用表面静止法发酵酿制枣醋的基础上,进一步研究探讨了四个单因素对其醋酸发酵产酸含量的影响,得出结论:醋酸发酵温度为35℃,添加含量为6.67%酸度为2.4 g/dL的猕猴桃醪液,膜面积与醪液体积比为0.2 cm2 /mL,调整进入醋酸发酵时酒精度至9%,同时通过正交试验对其进行优化设计,得出最优组合.     

杏果醋液态深层发酵工艺优化

采用酒精发酵和液态深层醋酸发酵两步法,研究了杏果醋的发酵工艺。通过L9(34)正交试验优化得到最佳酒精发酵工艺条件为:初始糖度16°Bx、酵母接种量3%、酒精发酵温度30℃,发酵液的酒精度达8.6%。采用4因素二次通用旋转组合试验设计,通过响应面法对醋酸发酵条件进行了研究。结果表明,起始酒精度、醋酸菌接种量、摇床转速及发酵温度4个因素对杏果醋总酸含量有极显著影响(P<0.01)。在初始酒精度为6.7%、醋酸菌接种量为13%、发酵温度为34℃、摇床转速为153 r/min的最佳工艺条件下,杏果醋酸发酵液的总酸(以醋酸计)为7.11 g/100 mL,挥发酸(以醋酸计)为6.23 g/100 mL。     

红枣醋生产中醋酸发酵阶段最佳工艺条件的研究

对红枣醋生产中醋酸发酵阶段的最佳工艺条件包括醋酸菌的筛选、发酵温度、醋酸菌接种量、初始酒度、初始pH值、装液量等对红枣醋醋酸发酵的影响进行了研究.结果表明:红枣醋醋酸发酵的最佳工艺条件为采用醋酸菌A1为发酵菌种,发酵温度34℃、接种量11%(v/v)、初始酒度为7%(v/v)、初始pH值3.0、装液量40%(v/v),发酵时间5 d,最终总酸含量可达到41.3 g/L.     

新疆骏枣果醋的发酵工艺研究

以新疆骏枣为原料,采用AS 1.41和沪酿1.01醋酸菌进行醋酸发酵,确定其最佳的醋酸发酵条件.考察了初始酒精度、发酵温度、接种量、pH、发酵时间和装液量对发酵效果的影响.试验得出最佳醋酸发酵工艺条件为菌种接种量为7％、初始酒精含量为6％、温度为30℃、装液量为65％.在此条件下进行发酵试验,所得产品醋酸含量达6.75％,得率为86.20％.     

杨梅果醋发酵工艺研究

以杨梅为原料,采用表面静止发酵方式,先后经过酒精发酵和醋酸发酵制得杨梅醋。在醋酸发酵过程中,通过单因素实验和正交实验,确定了果醋发酵的最佳工艺参数。实验结果表明,最佳醋酸发酵条件为：温度为26℃、接种量为6％、装液量为200ml／L,酒精度为5％时醋酸菌的转酸率最高。参考醋酸发酵过程中花色苷浓度的变化趋势,选择最佳发酵周期为10d。     

正交旋转试验优化产Ⅱa类细菌素乳酸菌的扩大发酵条件

利用前期实验数据,通过五因子二次正交旋转试验对扩大发酵条件进行优化,考察了转速、装液量、接种量、温度和不同初始pH值对产Ⅱ a类细菌素屎肠球菌发酵的影响.得到发酵培养基最佳条件:转速150 r/min.接种量2%,装液量450mL,温度30℃,初始pH值6.5.     

红茶菌发酵条件的控制研究

将分离筛选得到的乳酸菌、醋酸菌和酵母菌进行配比得到红茶菌复合菌种,分别讨论培养基pH值、溶氧量、温度和时间对培养结果的影响。结果表明：乳酸菌、醋酸菌、酵母菌按质量配比2:2:1,即总接种量5%、最适初始pH值为5.5、装液量为40%(即装液量100mL/250mL),在30℃、传统培养基培养5d的条件下,发酵效果最好。     

响应面法优化黄金梨果醋发酵条件

本文对黄金梨果醋的发酵条件进行优化.通过单因素试验研究发酵温度、接种量、酒精度和装液量4个因素对黄金梨果醋醋酸含量的影响,再结合中心组合响应面设计优化主要工艺参数,建立各因子与醋酸含量的数学模型.结果表明黄金梨果醋的最佳发酵条件是:发酵温度31.3℃,醋酸菌接入量11.41％,初始酒精度6.89％,250 mL三角瓶装液量105.20 mL.在此条件下,黄金梨果醋醋酸含量可达6.02225 g/100 mL.     

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