纳米ZnO/HDPE膜对奶酪的抗菌保鲜性

通过熔融共混法制备得到ZnO含量为0.5%纳米ZnO/高密度聚乙烯(HDPE)复合膜,对其进行表征和性能测试,并考察其对奶酪的保鲜性。结果表明,复合膜中的纳米ZnO粒子分散较均匀,相比于HDPE膜,纳米复合膜的力学性能和阻隔性能都得到一定程度的提高。该膜对奶酪包装后进行感官分值、pH值和微生物生长状况的测试发现,与纯HDPE膜所包装的奶酪相比,纳米ZnO/HDPE复合膜所包装奶酪的感官分值由66.0提高到73.0;pH值约为6.167,更接近标准样;奶酪溶液铺平板并培养48h后的菌落数(32×103CFU/mL)少于HDPE膜(82×103CFU/mL),这表明纳米ZnO/HDPE复合膜对奶酪上的微生物生长有很强的抑制作用,具有一定的抗菌保鲜性。     

纳米ZnO/HDPE复合膜的制备和性能研究

本文通过熔融共混和模压技术制备得到纳米氧化锌/高密度聚乙烯(纳米-ZnO/HDPE)复合膜,并考察了该膜的微观形态、机械性能、结晶性能以及阻隔性.结果发现,复合膜中改性纳米ZnO的含量较低(0.5wt%)时,纳米ZnO在HDPE中具有较好的分散性.随着改性纳米ZnO含量的增加,复合膜的拉伸强度和撕裂强度先增大后减小,ZnO含量为0.5wt%时,综合力学性能最佳.此外,改性纳米ZnO的添加能提高HDPE的结晶度,并能增强复合膜的阻隔性能.     

壳聚糖/磺丁基-β-环糊精纳米粒子的制备及其对海藻酸钠膜物理性能的影响

以壳聚糖（chitosan,CS）和磺丁基-β-环糊精（sulfobutylether-β-cyclodextrin,SBE-β-CD）为原料制备CS/SBE-β-CD纳米粒子,通过单因素试验探究不同条件对CS/SBE-β-CD纳米粒子粒径、多分散系数（polydispersity index,PDI）和Zeta电位的影响,得到CS/SBE-β-CD纳米粒子制备的最佳条件,并以透射电子显微镜（transmission electron microscope,TEM）和傅里叶变换红外光谱（Fourier transform infrared spectroscopy,FTIR）对CS/SBE-β-CD纳米粒子进行结构表征,探究添加CS/SBE-β-CD纳米粒子对海藻酸钠膜机械性能（拉伸强度、断裂延伸率）以及物理性能（膜厚度、水蒸气透过率（water vapor permeability,WVP））的影响。结果表明,CS/SBE-β-CD纳米粒子的最佳条件为CS分子质量100 kDa、CS溶液pH 4.0、CS质量浓度0.75 mg/mL、CS与SBE-β-CD质量比0.8∶1。该条件下制备的CS/SBE-β-CD纳米粒子粒径、PDI以及Zeta电位分别为245.1 nm、0.068和＋30.2 mV。TEM观察发现CS/SBE-β-CD纳米粒子粒径均一且为规则球形。FTIR分析结果显示,CS与SBE-β-CD之间发生了静电结合,同时CS/SBE-β-CD纳米粒子形成后氢键作用增强。与空白海藻酸钠膜溶液相比,当膜溶液中CS/SBE-β-CD纳米粒子的质量浓度为1.00 mg/mL时,复合膜的拉伸强度由18.18 MPa增加到29.15 MPa,断裂延伸率由38.91%下降至26.42%,WVP由0.36 g·mm/（m2·h·kPa）下降至0.21 g·mm/（m2·h·kPa）。本研究制备的CS/SBE-β-CD纳米粒子能够改善和提高海藻酸钠膜的机械性能与物理性能。     

PVA/PEI超细纤维负载纳米钯杂化材料的制备

通过静电纺丝技术制得了聚乙烯醇(PVA)/聚乙烯亚胺(PEI)超细纤维膜,使用戊二醛蒸汽交联使其具有水稳定性,进而将交联后的PEI/PVA超细纤维膜浸入PdCl2溶液中至吸附平衡,以硼氢化钠(NaBH4)为还原剂,于超细纤维膜表面原位合成Pd纳米粒子.用场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外(FTIR)、紫外可见分光光度计(UV)等技术表征了PVA/PEI超细纤维,交联后的PEI/PVA超细纤维膜及负载有Pd纳米粒子的PEI/PVA超细纤维膜.研究表明:交联后的PVA/PEI超细纤维膜具有良好的水相稳定性,Pd纳米粒子在PVA/PEI超细纤维膜表面均匀分布,负载有Pd纳米粒子的PEI/PVA超细纤维膜对Cr(Ⅵ)的还原反应具有良好的催化性能.     

无机纳米粒子增强大豆蛋白膜功能特性的比较

大豆分离蛋白作为完全可降解性的生物聚合物,无抗菌性、机械性能及阻隔性能差限制了其在包装领域中的应用,该研究通过将纳米ZnO和纳米TiO2分别加入大豆分离蛋白（Soy Protein Isolate,SPI）中制备SPI/纳米ZnO复合膜和SPI/纳米TiO2复合膜,并对复合膜的包装特性进行比较,确定一种更有利于提升大豆分离蛋白基薄膜相关性能的纳米材料。分析结果表明：纳米ZnO在SPI膜液中的分散性优于纳米TiO2在SPI膜液中的分散性,纳米ZnO和大豆蛋白的相容性更好,且成膜后能更好的发挥协同作用,SPI/纳米ZnO复合膜较SPI/纳米TiO2复合膜的机械性能、阻隔性能和抗菌性能更为突出（P<0.05）。纳米ZnO和大豆蛋白以3%的质量比制备复合膜时,SPI/纳米ZnO（SZ3）复合膜相比较于SPI膜,拉伸强度从6.64 MPa升至18.33 MPa,水蒸气透过率从 20.63×10-2 g•mm/(m2•h•kPa)降至2.94×10-2 g•mm/(m2•h•kPa),氧气透过率从3.32×10-5 g•m/(m2•d•kPa)降至1.54×10-5 g•m/(m2•d•kPa)。此外,复合膜对大肠杆菌和短小芽孢杆菌表现出优异的抗菌性能,抑菌性随着纳米粒子的添加呈上升趋势,在活性包装应用中具有极大潜力。以上研究结果将为大豆蛋白基薄膜的未来应用提供理论参考。     

纳米TiO2改性壳聚糖膜的制备及性能初探

本文采用溶胶-凝胶法制备了纯壳聚糖膜及纳米TiO2/壳聚糖复合膜,用X-衍射(XRD)、红外光谱(FI-RT)、扫描电镜(SEM)进行表征,并测试了TiO2/壳聚糖膜的热稳定性及机械性能.X-衍射(XRD)表明,添加TiO2改变了壳聚糖原来的排列;红外(FT-IR)分析表明,壳聚糖复合膜中存在Ti-O键;扫描电镜(SEM)表面,纳米TiO2较好地分散在壳聚糖中,形成无机粒子嵌入式有机/无机网络结构,有机相为连续相,分散性较好;通过测试复合膜的起始和终止分解温度表面,加入纳米TiO2能够提高了壳聚糖分子链加热过程中断裂所需要的能量,提高了壳聚糖纳米二氧化钛复合膜的热稳定性;拉伸测试表明,添加适量纳米TiO2后能提高断裂强度.     

棉织物表面ZnO纳米棒的原位生长和掺杂改性

以硝酸锌和六亚甲基四胺为原料,聚乙二醇2000表面活性剂为形貌控制剂,采用低温水浴法,在棉织物表面实现稀土钕掺杂ZnO纳米棒阵列的原位生长;同时采用X射线衍射仪、扫描电子显微镜和紫外分光光度计等对制备的样品进行结构表征和性能分析。结果表明,当掺入物质的量之比为3%的钕时,可明显改善ZnO纳米棒表面状态,有利于产生更多的表面羟基,抑制光生电子和空穴的复合;Nd掺入ZnO晶格,增大了ZnO纳米棒的直径和比表面积,显著提高光催化活性和抗紫外线性能。表面生长有Nd/ZnO纳米棒阵列的棉织物,抗紫外线指数UPF值由掺杂前的360.9提升至471.5;在太阳光下照射8h,对亚甲基蓝溶液(MB)的降解率由掺杂前的56.3%跃升至87.6%。     

魔芋葡甘聚糖/油酸修饰纳米ZnO复合抗菌膜的制备与表征

为提高纳米氧化锌（ZnO）在魔芋葡甘聚糖（konjac glucomannan，KGM）中的分散性，以增强纳米复合膜的抗紫外线性能和抗菌性能，通过油酸（oleic acid，OA）对纳米ZnO进行修饰，制备OAZnO溶液，并采用浇铸法制备KGM/OAZnO纳米复合膜，通过流变学分析、傅里叶变换红外光谱分析、X射线衍射分析、微观结构观察、热重分析以及理化性质测定，研究OAZnO的添加对KGM膜结构和理化性质的影响。结果表明，OA提高了纳米ZnO的分散性，傅里叶变换红外光谱分析证实纳米ZnO与KGM分子间形成了较强的氢键，X射线衍射光谱结果表明纳米ZnO中的Zn2＋与KGM链上的—OH形成配位键；同时，适量OAZnO（0.49 mL）使纳米复合膜包装机械性能和阻水性能得到增强，其水蒸气透过率较KGM膜降低了35.62%，拉伸强度提高了79.26%。此外，紫外光谱分析和抗菌实验结果表明KGM/OAZnO纳米复合膜具有较强的紫外阻隔性能和抗菌性能。综上，OAZnO的添加可以提高纳米复合膜综合性能，且OAZnO溶液添加量为0.49 mL时最强，可以作为功能性食品包装膜。     

壳聚糖/植酸钠/纳米TiO_2-ZnO在木材表面的自组装及抗紫外性能探究

采用层层自组装方法在木材表面负载了壳聚糖/植酸钠/纳米TiO_2-ZnO二元复合膜(CH/SP/纳米TiO_2-ZnO),并设置了以组装方式、聚阴离子和纳米粒子溶液浓度及比例、浸泡时间、负载层数为变量的多组试验,探讨了二元复合膜在木材表面的抗紫外机理。通过配备有能谱仪(EDS)的扫描电子显微镜检测(SEM)和人工加速紫外老化测试,处理后的样品比未处理素材具有更好的抗紫外效果。结果显示,二元复合膜具有协同作用,较一元薄膜能进一步提高功能膜的性能效果,且充分的处理时间可以显著优化膜的性能,此外,负载层数与浓度不一定越大越好,本试验中的改良效果最佳参数为处理时间90 min,组装层数5层,二元TiO_2-ZnO共混,聚阴离子与纳米粒子浓度比例为2:1。     

基于低温水浴法的涤纶表面氧化锌纳米棒生长

通过简单的两步法在涤纶织物表面生成取向规整的一维ZnO纳米棒阵列。首先利用浸轧法将制备的纳米ZnO溶胶整理到涤纶织物上形成纳米ZnO微晶,然后以微晶为成核晶种,在由六水合硝酸锌及六亚甲基四胺组成的培养液中进行低温水热生长,直接在织物表面生成ZnO纳米棒阵列。场发射扫描电镜及透射电镜的观察结果显示ZnO纳米棒直径为40～50nm,长度为300～600nm。XRD分析表明所得ZnO纳米棒属于纤锌矿型的六角形晶体,且沿c轴生长。涤纶织物表面生长ZnO纳米棒后,UPF值从88.92提升至480.52,与未经处理的织物相比具有极佳的抗紫外线性能。     

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.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

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.     

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 Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.