淀粉接枝共聚物微球的合成与降解研究

在反相悬浮体系中以K2S2O8-NaHSO3引发N,N'-亚甲基双丙烯酰胺与淀粉的接枝共聚,制备了淀粉接枝典聚物微球.用人工肠液对所得淀粉微球进行体外降解,运用FT-IR、SEM、粒度分析仪对微球及其降解产物进行了表征分析,用正交实验分析了合成因素对微球粒径的影响.结果表明:共聚物微球形态圆整,平均粒径50.2μm,微球中存在酰氨基结构.正交实验表明:N,N'-亚甲基双丙烯酰胺和油水比对微球的平均粒径影响较大;体外降解表明:微球在3～4 h内基本维持稳定聚合结构,之后降解迅速.     

交联淀粉微球的制备与载药性能研究

以可溶性淀粉为原料,Span-80和Tween-80为乳化剂,液体石蜡为油相,N,N＇-亚甲基双丙烯酰胺（MBAA）及环氧氯丙烷（ECH）为交联剂,硝酸铈铵（CAN）为引发剂,采用反相乳液法制备淀粉微球。试验应用正交优化设计,选择淀粉浓度、油水比、交联剂MBAA用量、乳化剂用量和引发剂用量5个因素为考察对象,对淀粉微球的制备条件进行了优化。利用红外光谱和粒度分析仪对产物进行了表征。以胭脂红为模型药物,研究淀粉微球的载药性能。     

载药淀粉微球酶促降解的可控制性研究

采用酶催化的方式对淀粉微球进行可控降解,通过控制淀粉微球合成过程及降解催化剂酶的组成等,实现对淀粉微球进行可控降解。利用红外光谱仪、扫描电子显微镜对淀粉微球降解产物进行表征。结果表明,酶催化淀粉微球降解的最佳条件为：在模拟胃液2＋肠液3（同时含有胃蛋白酶、胰酶和α-淀粉酶）中降解．合成过程中交联剂的用量为0．06mol／L。FTIIK和SEM表明,微球粒径逐渐减小,持续降解大约10h。     

淀粉微球对Fe2+离子吸附性能研究

以可溶性淀粉为原料,在反相悬浮体系中合成N,N′–亚甲基双丙烯酰胺交联淀粉微球(CSM)为载体。研究淀粉微球对Fe2+ 的吸附行为,利用红外(FT-IR)、扫描电镜(SEM)、X 射线衍射仪(XRD)对微球及其吸附产物进行表征,研究其吸附机理。结果表明：淀粉微球对Fe2+ 吸附等温线符合Langmuir 等温方程,对其吸附等温线进行拟合,相关性较好。在室温条件下,pH 值为4.5,对Fe2+ 的吸附时间为60min,最大吸附量为0.866mmol/g,得出吸附速率方程,吸附Fe2+ 后微球结晶度降低。     

交联玉米淀粉微球合成及其吸附性能研究

以N,N′–亚甲基双丙烯酰胺为交联剂,用反相悬浮法合成交联玉米淀粉微球(CSMs),运用红外、X射线衍射仪、电镜、粒度分析仪对产物进行表征分析,测定淀粉及淀粉微球吸附阴离子表面活性剂(SDS)后pH值与Zeta电位,研究两者吸附性差异。实验表明,合成淀粉微球大小均一、结构致密、表面粗糙、孔隙发育良好,粒径在30μm以下微球占83%;与淀粉相比,随交联度增加,淀粉微球溶解度、溶胀度下降,吸水量增加,淀粉微球与阴离子表面活性剂间存在比淀粉更强吸附作用,可作为一种良好吸附剂。     

可降解淀粉微球的性能研究

以可溶性淀粉为原料,反相乳液聚合法合成可降解淀粉微球,并测定了它的粒度分布、红外光谱、降解性、载药性等.结果表明：可降解淀粉微球的平均粒径为15.423μm,94%分布在1～50 μm,8 h后被淀粉酶降解11.72%～24.58%,淀粉微球具有很好的可降解性.     

较小粒径淀粉微球最佳合成条件的研究

以可溶性淀粉为原料,环氧氯丙烷为交联剂,Span60为乳化剂,大豆色拉油为油相,采用逆相悬浮交联聚合法合成淀粉微球。通过正交试验探讨了合成较小粒径淀粉微球的条件。结果表明,淀粉乳浓度对淀粉微球粒径影响最大,较小粒径淀粉微球合成的最佳条件为：淀粉乳浓度12％,水相用量5mL,乳化剂用量0,6g,交联剂用量3mL。并在最佳条件下利用超声波配合乳化,以得到粒径更小更均匀的淀粉微球。     

较小粒径淀粉微球最佳合成条件的研究

以可溶性淀粉为原料,环氧氯丙烷为交联剂,Span60为乳化剂,大豆色拉油为油相,采用逆相悬浮交联聚合法合成淀粉微球。通过正交试验探讨了合成较小粒径淀粉微球的条件。结果表明,淀粉乳浓度对淀粉微球粒径影响最大,较小粒径淀粉微球合成的最佳条件为：淀粉乳浓度12％,水相用量5mL,乳化剂用量0,6g,交联剂用量3mL。并在最佳条件下利用超声波配合乳化,以得到粒径更小更均匀的淀粉微球。     

阴离子淀粉微球对Cd~(2+)的吸附及动力学研究

以可溶性淀粉为原料,N,N′-亚甲基双丙烯酰胺(MBAA)为交联剂,采用反相悬浮聚合得到中性淀粉微球,再用Na3P3O9进行阴离子化得到阴离子淀粉微球,用红外光谱和扫描电镜对其进行表征分析。研究阴离子淀粉微球对Cd2+的吸附行为,考察了pH、时间等因素对其吸附率的影响。结果表明:阴离子淀粉微球对Hg2+的吸附行为既符合Langmuir等温吸附方程又符合Freundlich等温吸附方程;同时,分别采用拟一级模型和拟二级模型考察了吸附动力学,并计算了这些动力学模型的速率常数,实验数据和拟二级模型计算结果之间有较好的相关性。     

淀粉微球合成条件的研究

以可溶性淀粉为原料,环氧氯丙烷为交联剂,Span60为乳化剂,环己烷和三氯甲烷为油相,采用逆相悬浮交联聚合法合成淀粉微球.通过单因素及正交实验探讨了各因素对淀粉微球平均粒径的影响.结果表明,水相用量对淀粉微球粒径影响最大,较小淀粉微球合成的最佳条件为:淀粉乳浓度10%,水相用量4mL,乳化剂用量0.5g,交联剂用量3mL.通过电镜照片表征了淀粉微球的微观结构.     

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