过氧化氢与漆酶的协同催化反应

本文研究了微量过氧化氢(H2O2)存在提高漆酶催化2,2′-连氮-双(3-乙基苯并噻唑-6-磺酸)(ABTS)反应的影响.采用顶空气相色谱技术测定了漆酶/H2O2体系中的O2产生与消耗量.结果表明,H2O2和漆酶之间在较短时间内存在着协同作用;加入一定量的H2O2能提高漆酶催化反应的速率;漆酶能够在较短的时间内催化H2O2的分解,微量H2O2与漆酶蛋白质作用,可使漆酶部分失活,但对漆酶活力的抑制不大.     

磁性固定化漆酶在苹果汁除酚中的应用研究

以磁性聚苯乙烯微球为载体，戊二醛为交联刑，制备出了磁性固定化漆酶。研究表明：固定化酶的Km值较游离酶小，最适温度与游离酶相同，最适pH较游离酶下降0．4个单位，热稳定性、pH稳定性和贮存稳定性均较游离酶有所提高。Fe^2 、Hg^2 、Cr^3 对固定化酶有抑制作用，Cu^2 对固定化酶有激活作用。抑制刑EDTA、DMSO对磁性固定化酶的抑制作用明显较游离酶小。固定化漆酶在40℃条件下处理2h后，苹果汁中多酚含量减少20％，而酶活力没有变化。     

高温碱性条件下漆酶活力测试方法的研究

用带控温装置的紫外可见光谱仪作为高温酶活检测平台,建立了以2,2’-连氮基-双-(3-乙基苯并二氢噻唑啉-6-磺酸)二铵盐(ABTS)为底物的高温、碱性漆酶活力测试方法,着重探讨了ABTS游离基(ABTS·+)消减对测试的影响,结果表明,本测试系统可供进行83℃以下动力学光谱分析,可用于漆酶的耐温、耐碱性研究,宜采用低离子浓度(4 mmol/L)缓冲液做介质,测试时长1 min,按此条件,在pH 4、7和10时,因ABTS·+消减而产生的误差绝对值分别低于1%,1.5%和5%。使用该系统测得诺维信漆酶最适pH为4.5、最适温度为60℃,还从三种担子菌漆酶中筛选出具有较高耐温性的乌芝酶。     

三种侧耳漆酶在烷基咪唑类离子液体中催化特性的研究

漆酶在纸浆漂白、纤维改性、废纸脱墨、废水氯代酚降解等方面有广阔的应用前景,使用离子液体/水混合溶剂可以提高漆酶催化不溶性底物合成或降解的效率,但同时会造成酶的活力下降。作者从红平菇、榆黄菇和糙皮侧耳菌糠中分离得到漆酶并研究了它们在烷基咪唑类离子液体中的催化特性。结果表明,红平菇、榆黄菇和糙皮侧耳漆酶在三种离子液体中均受到抑制作用。几种溶剂的抑制作用排序如下:乙醇丙酮1-乙基-3-甲基咪唑硫酸乙酯盐([EMIM]EtOSO_3)1-丁基-3-甲基咪唑磷酸二丁酯([BMIM]DBP)1-乙基-3-甲基咪唑醋酸盐([EMIM]Ac)。动力学分析表示,离子液体[EMIM]EtOSO_3与底物2,2'-连氮-二(3-乙基苯并噻唑啉-6-磺酸)(ABTS)对酶分子活性位点发生了竞争性结合,因此推测,漆酶在离子液体中的表观活力与初始酶用量无关,增加ABTS浓度有利于提高反应速率和酶的利用效率。     

漆酶对直接湖蓝5B的脱色性能研究

针对漆酶对染料的独特降解机理，将漆酶用于双偶氮结构的直接湖蓝5B溶液的脱色，确定其最适反应条件，结果表明：漆酶对这类染料有明显的脱色作用．染料溶液在酶质量浓度3g／L、pH4．5、30℃、60min日寸有最佳的脱色效果；讨论了不同添加剂（例如酸根离子、金属离子、表面活性剂）对脱色的影响．结果表明：Cu^2＋对脱色有明显的促进作用，而Fe^2＋和各类表面活性剂对脱色有抑制作用．     

韦伯灵芝漆酶的分离纯化及其性质

采用硫酸铵分级盐析、透析、聚乙二醇浓缩和高效液相色谱柱层析从韦伯灵芝TZC-1 发酵液中分离纯化得到电泳纯漆酶,其纯化倍数为37.1 倍,酶活性回收率为21.3%。活性-PAGE(聚丙烯酰胺凝胶电泳)结果表明该漆酶由一种同工酶组成,纯化漆酶经SDS-PAGE 检测显示为单一条带,其分子质量约为40kD。该漆酶催化底物ABTS 的最适反应温度为50～60℃,最适反应pH 值为4.6,在60℃以下和pH3.0～5.0 范围内保持稳定,以ABTS为底物的表观Km 值为13.8μmol/L。Fe2+ 完全抑制酶活,Al3+ 和Mn2+ 对该漆酶也有明显抑制作用,Hg+、Cu2+ 和Mg2+ 对该酶有明显激活作用,而Zn2+、Ba2+ 及K+ 对该酶活性影响不大。     

毛柄金钱菌漆酶的纯化与理化性质研究

本文通过盐析、超滤和DEAE-Sephadex A-25离子交换层析得到毛柄金钱菌漆酶,并对其理化性质进行了研究,考察了毛柄金钱菌漆酶最适宜反应温度和pH值、热稳定性和pH值稳定性、反应动力学常数、耐溶剂性质以及金属离子对酶活的影响。实验结果表明:毛柄金钱菌漆酶在60℃时酶活达到最大,最适反应温度为60℃,低于70℃时具有较好的热稳定性;该酶最适pH为4.0,在pH 4.0~4.5表现出较强的稳定性;毛柄金钱菌漆酶氧化ABTS的Km值为1.58×10-4mmol/L;乙醇、丙酮和二氧六环作溶剂时对毛柄金钱菌漆酶活性具有较强的抑制作用;Zn2+和Cu2+对漆酶有激活作用,而Fe2+、Fe3+则有明显的抑制作用。     

硬毛粗盖孔菌产漆酶条件优化及其对日落黄的降解作用

以硬毛粗盖孔菌(Funalia trogii)为研究对象,考察培养基组成及培养条件等对其发酵产漆酶的影响,并进一步研究漆酶对食用合成色素日落黄的降解脱色效果。结果表明,最适培养基组成及培养条件为:玉米淀粉25 g/L,蛋白胨2 g/L,Cu~(2+)1.5 mmol/L,香兰素1 mmol/L,培养温度30℃、初始p H6.0,摇床转速200 r/min,硬毛粗盖孔菌培养8 d后发酵液漆酶活力为(329±12) U/m L,是初始培养条件下的11.96倍。漆酶粗酶液对日落黄呈现出较高的降解脱色作用并可耐受高浓度底物(800 mg/L),50～200 mg/L日落黄脱色率均可达90%以上,漆酶介体ABTS可提升对日落黄脱色效率及速率,并降低高浓度底物对漆酶的抑制作用,曲酸的加入则抑制了漆酶活性,导致漆酶对日落黄的脱色率仅为7.14%。本研究为漆酶资源在食品行业的深入开发与应用提供理论依据。     

铜(Ⅱ)对漆酶活性的影响

以2，2—连氮—双(3—乙基苯并噻唑—6—磺酸)(ABTS)为底物，研究了Cu^2 离子对漆酶活性的影响。实验结果表明，漆酶的活性受pH的影响非常大；Cu^2 离子在不同的pH范围和浓度下，对漆酶的活性有不同的作用。     

以ABTS为底物测定漆酶活力的方法

以2,2’-连氮-双（3-乙基苯并噻唑-6-磺酸）（简称ABTS）为底物，采用分光光度计在420nm下测定漆酶活力，研究了酶活测定条件对酶活值稳定性的影响，确定了测定漆酶活力的方法：选择漆酶适宜的温度和pH，适当稀释漆酶（使漆酶稀释液的活力为27．7～55．3U／mL），测定漆酶催化分解0．5mmol／LABTS使吸光度值从0．15增加到0．20所经历的时间t，改变稀释倍数使t值在10-20s，根据相应的公式计算漆酶活力（漆酶活力误差为3％）．     

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.