河南华溪蟹金属硫蛋白分泌型表达载体的构建、表达及纯化

目的：构建河南华溪蟹金属硫蛋白（metallothionein,MT）分泌型表达载体并诱导其可溶表达。方法：采用基因重组技术,将河南华溪蟹MT基因亚克隆至碱性磷酸盐启动子（alkaline phosphatase promoter,phoA）分泌型原核表达载体,转化大肠杆菌BL21（DE3）,通过低磷酸盐诱导重组蛋白表达,经Ni2+螯合柱分离纯化后,利用紫外光谱扫描分析、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gelelectrophoresis,SDS-PAGE）及Western blotting检测鉴定重组MT。结果：phoA-MT分泌型表达载体构建成功,工程菌经低磷酸盐诱导后重组MT以可溶形式获得表达,紫外光谱扫描和Western blotting证实表达产物的正确性,SDS-PAGE分析其纯度较高,主要以单体和二聚体的形式存在,其分子质量分别约为7.5、15 kD。结论：成功实现了河南华溪蟹MT的重组表达。     

厚壳贻贝多糖的提取工艺优化及体外生物活性研究

以抗氧化和抗肿瘤活性为指导优化提取工艺,分别采用热水提取,两步联合酶解法（木瓜蛋白酶和胰蛋白酶）从厚壳贻贝中提取和分离纯化具有生物活性的贻贝多糖,对其进行基本理化性质分析和DEAE-Cellulose 52 柱层析分离纯化并进行体外抗氧化、抗肿瘤生物活性研究。通过对热水提取法,单一酶提法和联合酶提取法得到的贻贝多糖粗品进行理化性质分析和活性筛选,发现联合酶解提取得到的贻贝粗多糖在得率、纯度和生物活性上均优于其他方法提取得到的粗多糖,其提取粗多糖的得率为23.69%。联合酶提粗多糖体外抗氧化研究表明其对DPPH自由基、超氧阴离子自由基和脂质过氧化物清除的半最大效应浓度（concentration for 50% of maximal effect,EC50）分别为3.75、5.01 mg/mL和2.41 mg/mL;对体外前列腺癌DU-145细胞48 h,IC50为2.93 mg/mL。通过分离纯化后对各组分的得率和组成分析表明：联合酶提可提高贻贝多糖类糖胺聚糖（MT3）的含量,并达到13.5%,单糖组成主要为Man、GlcN、GlcUA、Gal和Fuc,分子质量约为18 kD。和其他组分相比,MT3 组分表现出良好的体外抗肿瘤活性,对体外前列腺癌DU-145细胞48 h,IC50 为2.71 mg/mL。通过活性追踪和工艺优化结果表明,热水提取后酶解工艺不仅可以降解蛋白提高多糖的纯度,而且还可以显著提高贻贝多糖中类糖胺聚糖的含量,而贻贝类糖胺聚糖是贻贝多糖的主要活性组分,具有良好的抗肿瘤活性。     

蟹油纳米乳液制备工艺及特性研究

为提高蟹油的稳定性,采用超声破碎法制备蟹油纳米乳液。通过单因素实验,考察乳化剂种类、乳化剂添加量、蟹油添加量、水添加量对蟹油粗乳液粒径的影响;利用Box-Behnken试验设计和响应面分析确定蟹油粗乳液的组成。结果表明:蟹油粗乳液中各成分最佳添加量为乳化剂(大豆磷脂)1.84 g (6.9%)、蟹油1.94 g (7.2%)、水23 mL (85.9%)。对制备的蟹油粗乳液进行进一步超声分散制得平均粒径为68 nm的纳米乳液,与粗乳液相比,超声分散得到的纳米乳液在不同温度(20～100℃)、pH(3～9)及钙离子浓度(100～500 m M Ca Cl2)下均表现出较好的物理稳定性。体外模拟消化实验中,纳米乳液的脂肪酸释放量及β-胡萝卜素生物利用度均高于粗乳液。用超声分散法制备蟹油纳米乳液,可提高蟹油作为添加剂在食品体系中的稳定性,使其具有更广泛的应用前景。     

沉淀聚合法制备葛根素印迹微球及其固相萃取葛根粉

以葛根素为模板分子,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂沉淀聚合法制备葛根素印迹聚合物微球。用扫描电镜观察微球形貌,静态吸附法测试聚合物的吸附行为。探讨分子印迹聚合物（molecularly imprinted polymers,MIPs）对葛根粗提液中葛根素的吸附、解吸附及固相萃取效能。结果表明,优化的葛根素MIP3对纯模板的静态吸附量达37.9 mg/g;对粗提液中目标化合物的吸附率为（96.3±1.81）%,以水、甲醇-醋酸（9∶1,V/V）及50%甲醇溶液为洗脱剂的单次解吸率为27%～34%,用水从MIP3上解吸出的总溶液经脱除溶剂后,所获粗品葛根素含量最高,达（37.4±2.87）%。在优化条件下,通过MIP3固相萃取葛根粗提液,葛根素回收率达71.6%,产品纯度高于75%。     

桑黄提取物的体外抗氧化、降血糖及降尿酸活性

为了解杨树桑黄不同提取物的生物活性,采用超声辅助法制备了杨树桑黄粗多糖和醇提物,分析了二者主要成分及其含量,比较了二者体外抗氧化、降血糖及降尿酸活性。研究发现桑黄粗多糖中总糖含量为74.87%,蛋白质含量为6.61%,糖醛酸含量为4.84%,硫酸基含量为2.59%;桑黄醇提物中总酚含量为35.72%,总黄酮含量为8.98%,总三萜含量为5.82%,总甾醇含量为7.36%。此外,桑黄粗多糖和醇提物具有较强的DPPH自由基、ABTS自由基、羟自由基清除能力和一定的还原力。体外降血糖及降尿酸实验表明桑黄多糖和醇提物对α-淀粉酶、α-葡萄糖苷酶与黄嘌呤氧化酶均有一定抑制作用,但桑黄醇提物降血糖和降尿酸活性明显优于桑黄多糖;另外桑黄醇提物对α-葡萄糖苷酶抑制作用IC50值为0.43 mg/mL,远低于阿卡波糖IC50值（0.87 mg/mL）。与桑黄多糖相比,桑黄醇提物具有较强的体外抗氧化、降血糖及降尿酸活性,这为充分利用桑黄资源、开发桑黄功能性食品或医药保健品提供了理论依据。     

葡萄皮中白藜芦醇提取条件优化

采用响应面优化双水相体系萃取葡萄皮中的白藜芦醇。选取（无水乙醇＋丙酮）质量分数、硫酸铵质量分数、粗提液质量分数三个因素,利用Box-Behnken Design研究各因素交互作用对白藜芦醇萃取率的影响。结果表明,优化萃取工艺条件为（无水乙醇＋丙酮）质量分数22.3%、硫酸铵质量分数24.0%、粗提液质量分数12.6%,在此条件下,白藜芦醇的萃取率可达89.16%。     

壳聚糖和褪黑素复合涂膜处理对鲜切西兰花品质及叶绿素变化的影响

以鲜切西兰花（Brassica oleracea L. var. italica Planch.）为实验材料，分别采用5 g/L壳聚糖（chitosan,CTS）、100μmol/L褪黑素（melatonin,MT）单独及CTS和MT复合涂膜处理，通过感官评价、生理生化指标测定以及质构分析，研究在（15±1）℃、相对湿度85%～90%条件下贮藏期间各处理组鲜切西兰花品质及叶绿素代谢情况。结果表明：CTS和MT单独或复合处理均有效地保持了鲜切西兰花的感官品质，贮藏第7天，CTS、MT单独和复合处理组西兰花感官评分分别为对照组的3.36、2.83倍和5.17倍。与对照组相比，CTS和MT复合处理可显著抑制西兰花叶绿素降解酶活力（P<0.05），从而抑制叶绿素降解，同时显著降低鲜切西兰花质量损失率和呼吸强度（P<0.05）。与对照组相比，CTS和MT复合处理组贮藏第5天时总叶绿素含量提高83.80%，叶绿素酶（chlorophyllase,CLH）、脱镁螯合酶（Mg-dechelatase,MDcase）、脱镁叶绿素酶（pheophyllase,PPH）和脱镁叶绿酸a加氧酶（ph...     

电感耦合等离子体质谱法分析海蟹中的砷元素分布特征

分别采用电感耦合等离子体质谱（inductively coupled plasma mass spectrometry,ICP-MS）法和高效液相色谱-ICP-MS测定4 种海蟹（青蟹、三疣梭子蟹、日本鲟和细点圆趾蟹）及其不同部位（胸肌肉、钳肉、肝胰腺、性腺（雌）和鳃）中总砷及砷形态分布特征。样品加酸、微波消解后采用ICP-MS法测定总砷;样品经稀硝酸溶液提取、正已烷脱脂净化后,采用Dionex IonPac AS19保护柱（50 mm×4 mm）及AS19阴离子交换柱（250 mm×4 mm,10 μm）作为分析柱、pH 9.5的50 mmol/L碳酸铵溶液作为流动相等度洗脱的液相分离条件和优化后的ICP-MS条件,测定砷甜菜碱（arsenobetaine,AsB）、一甲基砷、二甲基砷、三价砷（As（III））、五价砷（As（V））5 种砷形态含量。经方法优化后,5 种砷化合物的标准溶液在0～300 μg/L质量浓度范围内,呈现良好的线性关系（r2＞0.998）,检出限为0.008～0.014 mg/kg,定量限为0.025～0.055 mg/kg;在样品中添加0.4、1.0 mg/kg和2.0 mg/kg的水平下,加标回收率为70.0%～105.0%,相对标准偏差低于5%;158 个海蟹类样品中总砷含量范围为0.37～35.81 mg/kg,整蟹及分部位的砷形态物测定数据表明海蟹体内均以毒性较低的AsB为主,AsB占其总砷含量的60.9%～99.4%,无机砷含量均值在0～0.12 mg/kg之间,无机砷含量均未超过国家标准限量值;总砷和AsB的含量基本都呈现出细点圆趾蟹＜青蟹＜三疣梭子蟹＜日本鲟、同一品种下性腺（雌）＞肝胰腺＞蟹胸肌肉＞蟹钳肉＞蟹鳃的变化趋势,说明海蟹富集砷能力较强,性腺和肝胰腺是其砷富集的主要器官。     

芽球菊苣根粗多糖提取工艺优化及其体外抗氧化活性和相对分子量分析

目的:以印度芽球菊苣根为原料优化粗多糖的提取工艺,测定其抗氧化性及相对分子量。方法:考察料液比、水浴温度和水浴时间对菊苣根粗多糖得率的影响;采用Box-Behnken结合Matlab分析法优化粗多糖热水浸提法提取工艺;测定所提菊苣根粗多糖体外羟自由基清除能力和还原力;纯化后分析中性糖和酸性糖的平均相对分子量。结果:经过单因素和Box-Behnken设计优化试验,得到最佳提取工艺为:料液比2.74:100 g/mL,水浴温度72 ℃和水浴时间165 min,此时菊苣根粗多糖得率的理论预测值为40.32%,经验证实际值为39.99%±0.43%,与预测值差异不显著（P>0.05）;经Matlab分析,当提取时间取较高值（C=165 min）,料液比2.4:100～3.1:100 mL/g,水浴温度70～74 ℃,粗多糖得率可以取得较大值。按照上述最优工艺所提菊苣根粗多糖具备羟自由基清除能力（IC₅₀值为1.36 mg/mL）和Fe3+还原力（3 mg/mL对应吸光值0.21）,且与浓度呈现正相关。此外,采用高效液相色谱（High Performance Liquid Chromatography,HPLC）测得菊苣中性糖和酸性糖峰型良好,酸性糖峰高且窄表现出较高的纯度,中性糖和酸性糖平均相对分子量分别为10072.07和2388.13 Da。结论:Box-Behnken优化法结合Matlab分析法优化菊苣根粗多糖提取工艺切实可行,所提粗多糖不仅高得率,也兼具良好的体外抗氧化能力,其中,酸性糖纯度较高,中性糖分子量较大。     

解淀粉芽孢杆菌抑菌物质粗提取的优化及分析

为探究解淀粉芽孢杆菌（Bacillus amyloliquefaciens）A13抑菌物质适宜提取方法,分别采用硫酸铵盐析法、酸沉淀法、甲醇抽提法、乙酸乙酯萃取法进行抑菌粗提液的制备,并通过SuperdexTM75凝胶层析柱分离纯化。结果表明,以80%饱和硫酸铵法制备粗提液抑菌效果最佳,抑菌圈直径为23.67 mm,蛋白质量浓度最高,为582.50 μg/mL,其回收率为17.8%;以甲醇抽提法制备粗提液的抑菌圈直径为25.17 mm,其回收率最高,为32.1%,蛋白质量浓度为505.00 μg/mL;以酸沉淀法制备粗提液的抑菌圈直径为22.67 mm,其回收率与蛋白质量浓度分别为13.7%与273.75 μg/mL;以乙酸乙酯法制备粗提液时,乙酸乙酯与发酵液为3∶1（V/V）的抑菌效果最佳,抑菌圈直径为25.5 mm,并且其回收率和蛋白质量浓度分别为23.6%和255.20 μg/mL。因此,硫酸铵盐析法为粗提解淀粉芽孢杆菌A13抑菌物质的适宜方法。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status