高产β-葡萄糖苷酶野生酵母的筛选及产酶能力差异性分析

为了比较分析野生酵母菌产β-葡萄糖苷酶的情况,筛选高产β-葡萄糖苷酶的酵母菌株,该研究采用七叶灵显色法和4-硝基苯基-β-D-吡喃葡萄糖苷（p-NPG）显色法对从宁夏贺兰山东麓分离的941株野生酵母的产β-葡萄糖苷酶能力进行筛选,通过WL培养基上的酵母菌落形态和26S rDNA D1/D2区的序列分析对所有酵母菌株进行分类鉴定,并且对酵母产β-葡萄糖苷酶能力进行差异性分析。 结果表明,941株酵母被鉴定为14个种,且筛选出了4株酵母菌高产β-葡萄糖苷酶：菌株SLY-4（98.51 U/L）、F2-24（76.93 U/L）、 F2-16（62.72 U/L）和HX-13（47.95 U/L）。 产酶能力差异性分析表明β-葡萄糖苷酶广泛分布于14种酵母,但是产酶能力表现出明显的种间和种内差异性。     

如皋长寿村人群肠道抗氧化乳酸菌筛选

为获得能应用于功能性食品的高抗氧化性能乳酸菌,测定了30株分离自江苏如皋长寿村人群肠道中的乳酸菌发酵液清除自由基能力和还原能力,并对初步获得的4株抗氧化性能较好的菌株发酵不同组分清除自由基能力、还原能力及抗氧化酶活性进行了测定。结果表明:4株菌发酵液抗氧化性能不等同于其各组分抗氧化性能总和,且发酵上清液抗氧化性能显著高于其菌体和胞内提取物。获得综合抗氧化性能较好的2株菌L10和L13,两株菌发酵上清液对羟自由基清除率分别为56.4%和64.8%,对DPPH自由基清除率分别为51.8%和53.5%;两株菌发酵上清液还原活性A700nm分别为2.523和2.540;两株菌发酵上清液T-SOD活性分别为32.802U/mL和33.825U/mL,GSH-Px活性分别为37.273U/mL和45.012U/mL。两株菌经鉴定分别为发酵乳杆菌和干酪乳杆菌。     

黑加仑酵素发酵工艺优化及其体外抗氧化性能

为开发黑加仑酵素产品,对酵母菌发酵的黑加仑酵素的发酵工艺条件进行优化。以总抗氧化能力和SOD酶活力为指标,通过单因素试验和正交试验对酵母菌发酵时间、接种量、初始糖度和发酵温度进行了优化。结果表明:酵母菌发酵制备黑加仑酵素的最佳发酵工艺条件为:发酵时间为96 h、酵母菌接种量为0.07%、初始糖度为20%、发酵温度为28℃。在此最佳工艺条件下,制备的黑加仑酵素总抗氧化能力为880.60 U/mL, SOD酶活力为4 873.13 U/mL,该酵素中含有柠檬酸(2 745.27 mg/L)、苹果酸(448.65 mg/L)和奎宁酸(188.89 mg/L),莽草酸(23.48mg/L)、抗坏血酸(19.59 mg/L)和草酸(19.59 mg/L)。同时,抗氧化活性研究表明:黑加仑酵素对超氧阴离子自由基、DPPH自由基和羟自由基具有良好的清除能力。该试验结果为黑加仑酵素的工业化生产提供理论依据。     

清香型白酒大曲中产酶酵母的筛选与发酵特性研究

对清香型白酒大曲筛选得到的两株酵母，采用DNS法和福林酚法进行产淀粉酶能力和蛋白酶能力的检测；采用顶空固相微萃取气相色谱质谱法（HS-SPME-GC-MS）对两株酵母模拟固态发酵产物的挥发性香气成分进行检测。结果表明，两株酵母菌分别为Saccharomycopsis fibuligera(JM1-1)和Wickerhamomyces anomalus(JM1-2),JM1-1既产淀粉酶（68.640 U/mL）又产蛋白酶（67.702 U/mL）,JM1-2只产淀粉酶（30.352 U/mL），并且JM1-1产淀粉酶能力明显高于JM1-2。在其固态发酵产物中，酯类种类最多，相对占比最高，两株酵母的产酯生香能力较强，对白酒的香气有重要贡献。     

水塔老陈醋大曲酵母的分离鉴定及产乙醇和乙酸乙酯特性

采用传统分离培养方法,从水塔老陈醋大曲中分离纯化出21株酵母菌,利用26S r DNA D1/D2序列分析方法结合形态学特征,对分离纯化的酵母菌进行鉴定,并用其发酵糯米糖化液,用静态顶空-气质联用的方法测定发酵后乙醇和乙酸乙酯的含量。结果发现:21株酵母菌鉴定结果为2株弗比恩酵母(Cyberlindnera fabianii),8株扣囊复膜酵母(Saccharomycopsis fibuligera)、6株异常威克汉姆酵母(Wickerhamomyces anomalus)、3株葡萄牙棒孢酵母(Clavispora lusitaniae)、2株东方伊萨酵母(Issatchenkia orientalis)。21株菌株发酵后产物乙醇和乙酸乙酯的含量存在较大差别,其中产生乙酸乙酯和乙醇最多的菌株分别为异常威克汉姆酵母m12(含量为4.4415 g/L)和扣囊复膜酵母q25(含量为48.577 g/L);产生最少的则分别为扣囊复膜酵母q6(含量为0.0037 g/L)和东方伊萨酵母q12(含量为11.4555 g/L)。提示老陈醋大曲中不同种类的酵母菌在发酵中对乙醇和乙酸乙酯具有不同的贡献。     

亚麻籽粕制备小分子抗氧化活性肽

目的:以亚麻籽粕为原料,提取蛋白并制备抗氧化活性肽。方法:利用碱性蛋白酶、中性蛋白酶和胰蛋白酶酶解蛋白,并通过测定总抗氧化能力(Ferric ion reducing antioxidant power,FRAP)、羟自由基清除能力和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)(2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)阳离子自由基清除能力表征酶解产物的活性。使用十二烷基硫酸钠-聚丙烯酰氨凝胶电泳和凝胶色谱法分析蛋白和酶解产物的分子质量(mw)分布。利用高效液相色谱-串联质谱联用技术分析鉴定最具有抗氧化活性组分。结果表明,对于高分子质量(3～10 kDa)和低分子质量(3 kDa)的蛋白多肽,低分子质量多肽(碱性蛋白酶)的抗氧化活性优于其他。10 mg/mL低分子质量多肽(碱性蛋白酶)的FRAP相当于(1.77±0.03)mmol/L的FeSO_4,羟自由基清除率为(57.13±1.47)%,清除ABTS阳离子自由基的能力(以Trolox当量浓度计算)为(1.19±0.03)mmol/L。通过凝胶色谱分离的最具抗氧化活性组分F2的蛋白质量占整体组分的20%,0.1 mg/mL组分F2的FRAP相当于0.29 mmol/L的FeSO_4,占整体组分活性的45.3%。亚麻籽粕蛋白氨基酸组成齐全,含人体所需的8种必需氨基酸,是一种优质的植物蛋白;蛋白酶解的特异性和肽段分子质量共同影响亚麻籽蛋白多肽的抗氧化活性;亚麻籽粕可以制备高抗氧化活性多肽。     

牛栏山二锅头酵母菌多样性研究及其代谢产物分析

从牛栏山清香型白酒发酵酒醅中共获得120株酵母菌,对其26S rDNA D1/D2区测序分析,对分离酵母菌进行鉴定,并分别以 高粱和酒醅作为酵母培养基,分析不同种酵母菌的代谢产物。结果表明,共分离鉴定得到9株酵母菌,在高粱培养基中,库德里阿兹氏 毕赤酵母（Pichia kudriavzevii）和异常威克汉姆酵母（Wickerhamomyces anomalus）乙酸乙酯产量较高,分别为969.0 mg/L和541.4 mg/L, 9种蒸馏液中正丙醇、异丁醇、异戊醇含量均高于对照组,尼泊尔德巴利酵母（Debaryomyces nepalensis）发酵产乙醛能力最高（58 mg/L）; 在酒醅培养基中,9株酵母菌代谢产物中共检测到24种酯、9种醇、5种酸、2种酮、2种醛、2种酚及1种呋喃,其中W. anomalus产乙酸乙 酯能力最强4 494.27 μg/L,P. kudriavzevii具有较强的产乙酸乙酯、苯乙醇、异丁醇及异戊醇能力,分别为546.21 μg/L、724.96 μg/L、 31.56 μg/L及142.52 μg/L,膜醭毕赤酵母（Pichia membranifaciens）产乙酸能力最强（498.56 μg/L）。     

树莓酒自然发酵过程中酵母菌的分离与鉴定

目的:从树莓酒自然发酵过程中分离和鉴定酵母菌,目的是筛选适宜树莓酒发酵特点的专用酵母菌株。方法:采用传统微生物分离纯化技术与和26S r DNA D1/D2区序列分析相结合的方法,从树莓酒自然发酵的不同时期分离纯化酵母菌,结合菌落和细胞显微形态特征进行区分,随机选择代表菌株进行26S r DNA D1/D2区序列分析。结果:从树莓酒自然发酵过程中共分离出323株酵母菌,形态学初步鉴定为12类,分子鉴定为分属于5个属的7种酵母菌,分别为葡萄汁有孢汉逊酵母(Hanseniaspora uvarum)、东方伊萨酵母(Issatchenkia terricola)、酿酒酵母(Saccharomyces cerevisiae)、覆膜孢酵母属亚种(Saccharomycopsis crataegensis)、叉开假丝酵母(Candida diversa)、东方拟无枝酸菌(Candida sorboxylosa)和假丝酵母属亚种(Candida stellimalicola)。结论:传统的微生物培养形态区分与分子鉴定技术结合,对筛选树莓酒自然发酵过程中的酵母菌准确有效。     

笃斯越桔中酿酒酵母菌的筛选、鉴定及特性研究

从口感好、自然发酵的笃斯越桔果汁中分离出140株酵母菌.经过对酵母菌产气、产酒精情况的测定以及发酵酿酒后感官评定,筛选出4株酵母菌,分别编号为C13、C18、D07和D15.对这4株酵母菌进行形态学和生理学特征鉴定以及26SrDNA D1/D2区序列分析,最终鉴定出4株酵母菌为同一种菌,即酵母属(Saccharomyces )中的酿酒酵母(Saccharomyces cerevisiae).结合商业葡萄酒活性干酵母进行比较分析,选择优良菌株D15作为实验菌株,测定其生物特性,结果表明D15具有较好的发酵特性、耐受特性和快速生长特性.D15在20°Bx、pH 3.5笃斯越桔果汁中24℃发酵9d,残糖量为2.8 g/L,酒精度(V/V)为12.5%,可以作为笃斯越桔酒酿造的优选菌株.     

两种分子标识在酵母分子鉴定中的比较

rDNA序列同源性分析是一种通用的酵母分子鉴定方法,26S rDNA D1/D2区域和rDNA内部转录间隔区(Internal Transcribed Spacer,ITS)是rDNA序列同源性分析中最为常用的两种分子标识。同时使用这两种分子标识对20株分离自水果表面的酵母菌株进行分子鉴定,结果显示19株酵母分离物的鉴定结果相一致,两种分子标识序列在认定酵母种内和种间关系时都拥有足够的差异,能将大部分酵母菌株直接鉴定到种一级水平。     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press