微波辐射常压合成丁酸乙酯

采用微波辐射技术,在对甲苯磺酸的催化下,以甲苯为带 水剂,快速合成了丁酸乙酯。最佳反应条件为:乙醇和丁 酸的摩尔比为2.8:10(mol/mol),催化剂1.3g,微波功率 665w,微波辐射时间10min,带水剂为5mL,产率达94％ 以上。     

微波法快速合成香料糠酸正丁酯

在对甲基苯磺酸的催化下,利用微波辐射技术,在常压下快速合成了香料糠酸正丁酯。最佳反应条件为:醇酸物质的量比为3.5∶1,催化剂0.70g,带水剂5mL,辐射时间10min,微波功率700W,转化率达95.3%。     

微波-大孔树脂协同催化肉桂酸甲酯绿色合成新工艺的研究

研究了微波-大孔树脂协同催化合成内桂酸甲酯的新工艺,通过优化合成工艺,得到最佳工艺务件为:微波功率500W,微波温度80℃,微波时间16min,催化刺用量25%,酸醇比为1:25,产率迭84.0%.同时,对树脂的重复使用性能进行了测试,结果表明:树脂重复使用5次后,其催化性能保持不变.     

酶法合成癸酸甘油酯及其产物分布的研究

以固定化假丝酵母脂肪酶为催化剂,研究了无溶剂体系中甘油和癸酸直接酯化合成癸酸甘油酯的反应条件.考察了反应加酶量,底物摩尔比,温度,甘油含水量,反应过程中脱水方式等因素对癸酸转化率及最终产物分布的影响.结果表明:织物直接吸附假丝酵母发酵液制备的固定化脂肪酶能有效地催化合成癸酸甘油酯.反应的最优条件为:甘油与癸酸的摩尔比为1:1.5,反应温度为40℃,甘油含水量为4%,加酶量为0.25g/g癸酸.在最优反应条件下,癸酸转化率可达到98%.经过处理,固定化脂肪酶可重复使用4次以上.     

单癸酸甘油酯的合成及抑菌性研究

以癸酸、甘油为原料,经硼酸保护双羟基后,酯化反应合成单癸酸甘油酯.研究了催化剂及反应时间对合成的影响,确定了最佳合成条件.抑菌圈法测最小抑菌浓度,结果表明在实验浓度下,单癸酸甘油酯具有很好的抑菌活性.单癸酸甘油酯热稳定性很好,经121℃、30min处理,仍具有良好的抗菌效果,对空气、牛奶中混合微生物也具有良好的抑制性能.     

丙位癸内酯及其相应羟基酸对Yarrowia lypolitica菌株生长的影响

在生物转化蓖麻油合成丙位癸内酯的过程中,丙位癸内酯产率极低一直是制约生物法生产癸内酯技术工业化的重要因素。文中着重研究了丙位癸内酯及其相应羟基酸( 4 羟基癸酸)对Yarrowialypolitica菌株生长的影响。结果表明,相对于内酯,羟基酸对微生物细胞的生长的毒性要小得多     

法国白兰地特征风味组分癸酸乙酯的催化合成

以铁钾矾为催化剂,通过癸酸与乙醇反应合成了癸酸乙酯.研究了催化剂用量、反应时间、原料物质的量比等对酯化率的影响.结果表明,新型固体酸铁钾矾是合成癸酸乙酯的良好催化剂,在酸醇物质的量比为1:2,催化剂用量为0.6g(0.05mol癸酸),带水剂苯为15mL,反应时间为2.5 h的条件下,癸酸乙酯的酯化率可达98%.     

微波协同1-丁基-3-甲基咪唑硫酸氢盐离子液体催化酯交换合成肉桂酸正丁酯的研究

研究微波协同1-丁基-3-甲基咪唑硫酸氢盐催化酯交换反应合成肉桂酸正丁酯的新工艺,通过优化合成工艺得到了最佳工艺条件:肉桂酸甲酯的量为0.01 mol,酯醇摩尔比1∶8,催化剂用量为肉桂酸甲酯质量的16％,微波功率300W,微波温度为80℃,微波反应时间为45min,在此条件下,肉桂酸甲酯的最高转化率达36.07％.     

微波辐射-同步冷却辅助合成(乙基)麦芽酚酯香料化合物

描述了一种快速、绿色合成(乙基)麦芽酚酯香料化合物的方法。麦芽酚和乙基麦芽酚与酸酐在羧酸钠催化下反应,辅助以微波辐射-同步冷却合成了4种(乙基)麦芽酚酯。反应速率和转化率均明显高于传统回流方法,密闭条件下微波辐射反应速率和转化率大于常压条件。采用元素分析、红外光谱、氢核磁共振光谱和质谱对合成的4种(乙基)麦芽酚酯进行了结构鉴定,香气评价结果表明,4种(乙基)麦芽酚酯具有焦糖香、果香等香气。     

超高倍甜味剂N-[3-(3-羟基-4-甲氧基苯基)丙基]-阿斯巴甜的合成研究

开发安全,低成本,高甜度,性质稳定的甜味剂是食品工业的发展方向。文中从甜味机理出发,以3-羟基-4-甲氧基苯丙醛与阿斯巴甜为原料,通过钯碳催化,合成了N-[3-(3-羟基-4-甲氧基苯基)丙基]-阿斯巴甜。其中,由于疏水基团引入,甜度显著提高,约是蔗糖的23000倍,且合成工艺简单,产率高,为国内高倍甜味剂大型工业化提供了广阔前景。另外,文中还着重论述了重要中间体3-羟基-4-甲氧基苯丙醛制备,得率为49.8%,为开发新产品奠定了基础。     

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