黑曲霉木聚糖酶（xynZF-2）基因克隆、表达及酶学性质分析

利用RT-PCR技术从黑曲霉（Aspergillusniger）XZ-3S中成功克隆出木聚糖酶基因（xynZF-2）的cDNA序列（Genbank登录号为：JQ700382）。该基因核苷酸序列阅读框全长678bp,编码225个氨基酸,其中成熟肽为107个氨基酸。以重组质粒pUCm-T—xynZF-2为模板,扩增得到编码xynZF－2成熟肽的cDNA片段（624bp）。将其与表达载体pET－28a连接,构建重组表达载体pET－28a—xynZF－2,并转化大肠杆菌（Escherichiacoh）BL21（DE3）,获得重组工程菌BL21／xynZF-2。经IPTG诱导表达,木聚糖酶的的比酶活最高可达42．33U／mg。重组表达的木聚糖酶最适反应温度为40℃,最适反应pH为5．0,在碱性条件下具有良好的稳定性。Fe^3＋对酶的激活作用最为明显。     

鲜味八肽的表达载体构建及表达效果验证

鲜味肽是近年来新发现的呈味物质,但国内外对其呈味效果存在争议。导致这一争议的可能原因是验证鲜味肽呈味效果的方法主要是采用化学合成法。为了制备生物源鲜味肽,以便对鲜味肽呈味效果进行再评价,本文以争议性鲜味八肽为目标肽,采用基因工程法,构建了制备生物源鲜味肽的表达载体,并对其表达效果进行了验证。根据争议性鲜味八肽的一级结构Lys-Gly-Asp-Glu-Glu-Ser-Leu-Ala和大肠杆菌E.coli BL21(DE3)的密码子偏爱性,设计了该鲜味八肽的DNA序列,并将其克隆在pET-32a(+)上形成表达载体。通过菌落PCR检测阳性克隆、重组质粒鉴定及工程菌的诱导表达,结果发现,鲜味八肽的目的基因成功重组在pET-32a载体上,所得pET-32a鲜味肽重组载体转化大肠杆菌后能够正常表达融合蛋白。这为后续获得生物源鲜味八肽奠定了基础。     

一种新型凋亡素融合蛋白的克隆表达及活性测定

目的克隆表达EC—SOD3-凋亡素融合蛋白,并检测其生物活性。方法PCR扩增出apoptin序列,与表达载体EC—SOD3-pET-28a连接后在大肠杆菌BL21（DE3）中经IPTG诱导,表达产物进行Ni^2＋-NTA纯化和MTT活性检测。结果表达载体pET-28a—EC—SOD3-apoptin经酶切鉴定和序列分析,证明质粒构建正确,转化E．coli BL21（DE3）后,重组蛋白获得表达,Ni^2＋-NTA纯化后的凋亡素融合蛋白纯度达到85％以上,经噻唑蓝（MTT）法测定具有活性。结论成功构建了表达载体pET-28a-EC—SOD3-apoptin,并在大肠杆菌中表达了EC—SOD3．凋亡素融合蛋白,纯化的蛋白质具有诱导HeLa细胞凋亡的能力。     

人工设计短肽PF1和PF2的克隆表达及其对葡萄糖氧化酶活性的影响

人工设计并合成2 条等电点分别为12.01和3.18的短肽PF1、PF2，基因全长均为309 bp。以PF1-F、PF1-R、PF2-F和PF2-R为引物，扩增至pET-30a（＋）载体中进行克隆表达。经Ni-NTA分离纯化得到纯蛋白。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳与Western Blot分析表明：表达出的目的蛋白与预期估算大小一致。纯化后的短肽加入葡萄糖氧化酶（glucose oxidase，GOD）催化作用体系中，表明纯化后的短肽分别使GOD活力提高8.34%和降低6.88%。因此可以说明，人工设计的不同电短肽PF1、PF2可以促进或抑制GOD的催化作用，进一步拓宽GOD在食品发酵和食品保鲜方面的应用范围。     

养殖暗纹东方纯肌肉中呈味肽的分离鉴定

本文旨在从生鲜暗纹东方纯肌肉中提取呈味肽从而对暗纹东方纯肌肉中的呈味肽的结构特性进行相应研究。将生鲜养殖暗纹东方鱼屯肌肉水提物经Sephadex G15凝胶柱分离,得到3个多肽组分（分别为0-F1、0-F2和0-F3）,感官评价结合电子舌选择出具有最强烈的鲜味和kokumi感的组分0-F1。采用反相高效液相色谱（RP-HPLC）对其进行进一步分离得到2个组分0．F1．1和0．F1．2,电子舌鉴定显示O．F1．1组分有较强的鲜味。最后利用基质辅助激光解析电离飞行时间质谱（MALDI-TOF-MS）对RP-HPLC分离得到组分0-F1-1中呈味肽氨基酸序列进行测定,鉴定得到一种新的呈味七肽结构：Pro-A-A1a-B-Met＊-Cys-Arg（810．9046 Da,A和B均为氨基酸代码,Met＊表示氧化型甲硫氨酸）虽然肽段中含有大量的疏水性氨基酸,但该肽不具有苦味,而且有显著的浓厚感,其中含有的Cys残基可能是其具有kokumi感的关键。     

超滤对缫丝蚕蛹蛋白肽感官品质的影响

目的：分析酶解缫丝蚕蛹蛋白所得肽经超滤处理后的性质,为其深度开发利用提供参考。方法：超滤分离酶解缫丝蚕蛹蛋白肽,气相色谱-质谱联用仪（gas chromatography-mass spectrometer,GC-MS）测定挥发性成分。结果：缫丝蚕蛹蛋白肽经超滤后各组分（5.0 mg/mL）的明度（L*值）、偏向绿程度（a*值）、偏向黄程度（b*值）均为大于3 000 D组分＞酶解原液＞200～3 000 D组分,且颜色由中黄色（酶解原液）变为深黄色（大于3 000 D组分）和浅黄色（200～3 000 D组分）;121 ℃灭菌处理对它们的色泽无显著影响（P＞0.05）;各组分吸湿性强度为200～3 000 D组分＞酶解原液＞大于3 000 D组分,其中200～3 000 D组分的最高吸湿率达到42.24%;超滤后缫丝蚕蛹蛋白肽的气味由刺激性难闻气味（脱脂蚕蛹蛋白粉）转变为有肉香（200～3 000 D组分）、果香及甜香味（大于3 000 D组分）。结论：超滤提升了缫丝蚕蛹蛋白肽的感官品质。     

玉米肽的制备、特性与应用

玉米面筋粉（CGM）中蛋白质的功能特性能够用酶解的技术得以改善，改良后的CGM能更好地应用于食品工业。CGM用AS1．398酶处理后有30～50％的蛋白质转化为可溶性肽；经酶解后所得的玉米肽，流动性好、粘度低；热稳定性较好。在蛋白质强化饮料和一些功能性食品中能得到应用。     

麻疹病毒N蛋白原核表达纯化条件的优化

通过构建重组表达质粒,诱导表达纯化麻疹病毒N蛋白．将麻疹病毒N蛋白基因片段与载体pET-32a（＋）相连接,通过PCR方法扩增获得重组质粒pET-32a（＋）／N,然后将重组质粒转入大肠杆菌E．coliBL21（DE3）内,并优化诱导表达时间、温度、诱导剂浓度等条件．SDS—PAGE和Western blot蛋白印迹检测表明,麻疹病毒N蛋白分子质量约为60kD,表达产物用Ni—NTA亲和层析和DEAE纯化后,纯度达90％．     

石金钱龟低聚肽制备工艺优化及其抑制新冠病毒的潜能

为了探究石金钱龟低聚肽作为新冠肺炎病毒（SARS-CoV-2）药物开发原料的可能性,该研究用“风味蛋白酶+木瓜蛋白酶”组合对龟肉进行酶解,通过不同酶配比、加酶量、pH和酶解时间的单因素实验和正交实验确定最优工艺条件,制备出石金钱龟低聚肽。再通过HPLC-MS分离、Peak Studio解析、Peptide Ranker活性预测逐步筛选出活性较高的低聚肽,最后进行各低聚肽序列与SARS-COV-2棘突蛋白（S蛋白）的分子对接。结果显示,最佳工艺参数为风味蛋白酶:木瓜蛋白酶=7:3、加酶量7%、pH 5.5、酶解时间4 h,此时的水解度为42.56%;Peak Studio解析出可信度（ALC）>90%的肽共510条,经Peptide Ranker生物活性评估后筛选出6条低聚肽与S蛋白分子对接,低聚肽序列分别为：LDFFK、LDFFKAL、FRVL、AFRVL、AGGKPFQ、SPFRVT,其Docking Score 在-138.50~-169.68之间,其中LDFFKAL的Docking Score最低,为-169.68,说明该低聚肽抑制新冠肺炎病毒的潜能最强。总的来说,经工艺优化后石金钱龟龟肉的水解度大大增加,且制得的石金钱龟低聚肽有较强的抑制新冠肺炎病毒的潜能。     

安来霉素在肉鸡日粮中的应用研究

应用安来霉素，金霉素，杆菌肽锌三种抗生素药物添加剂，对１２００只ＡＡ肉鸡进行生产性能和经济效益对比，试验分三组，安来霉素组（１０ｍｇ／ｋｇ）金霉素组（１００ｍｇ／ｋｇ）杆菌肽锌组（７５ｍｇ／ｋｇ）。每组设４个重复组。采食安来霉纱饲养的鸡只，日增重比金霉素０．５６％（Ｐ〉０．０５），比杆菌肽锌组高６．１７％（Ｐ〈０．０５）。饲料转化率分别比金霉素组高１．４３％（Ｐ〉０．０５）。比杆菌肽锌组高７．２％     

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.     

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     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.