一步法制备两性淀粉干法工艺研究

以玉米淀粉为原料,利用干法生产工艺一步法制备出羧基型两性淀粉。通过单因素试验,确定影响两性淀粉取代度及反应效率各因素的最佳值。通过L9(34)四因素三水平两性淀粉正交实验,确定出制备两性淀粉的最佳工艺参数为:阳离子化反应,体系含水量为20%,反应温度75℃,反应时间3 h,NaOH与醚化剂摩尔比为3∶10。羧甲基化反应,反应温度70℃,体系含水量20%,反应时间3 h。     

干法制备氧化淀粉的工艺研究

以H_2O_2为氧化剂，在碱催化剂存在的条件下干法制备出氧化淀粉。并对反应温度、反应时间、反应体系水的质量分数、NaOH与淀粉的摩尔比和H_2O_2与淀粉的摩尔比对氧化淀粉羧基含量的影响进行了研究。在固定反应时间3h，以及H_2O_2与淀粉的摩尔比0.225的条件下，选择反应温度、反应体系水的含量、NaOH与淀粉的摩尔比为三因素，采用正交实验，确定出制备氧化淀粉的最佳工艺参数为：反应温度60℃、反应体系水的质量分数为26.5％、NaOH与淀粉的摩尔比为0.135。     

半干法制备低取代度阳离子淀粉的工艺研究

以玉米淀粉为原料,以3-氯-2羟丙基三甲基氯化铵(CHPTMA)为醚化剂,以NaOH为催化剂的条件下,半干法制备了低取代度阳离子淀粉。确定了半干法制备低取代度阳离子淀粉的工艺路线,研究了各反应因素对阳离子淀粉反应效率的影响,并以反应效率为指标,利用二次通用旋转试验建立了相应的回归方程,确定了最佳工艺参数为:NaOH与醚化剂的摩尔比1.85∶1,体系含水量20.49%,反应温度60.65℃,反应时间4.49h,最佳条件下制备的阳离子淀粉反应效率可达到89.48%,取代度为0.0335。     

干法合成阳离子淀粉的研究

讨论了干法制备阳离子淀粉工艺中阳离子试剂、催化剂用量及反应温度、反应时间等因素对取代度和反应效率的影响。研究表明最佳工艺条件是:淀粉、醚化剂及NaOH加入量的质量比为50∶18∶5,淀粉含水量为34%,反应温度60℃,时间5h,可以制备出取代度为0.289,反应效率为75%的高取代度阳离子淀粉。     

羧甲基淀粉干法制备工艺

采用干法制备了羧甲基淀粉 ,研究了各反应因素对羧甲基淀粉取代度和CH2 ClCOOH反应效率的影响 ,并以取代度为指标 ,利用二次通用旋转试验建立了相应的回归方程 ,确定了其最佳工艺参数为 :NaOH与CH2 ClCOOH摩尔比为 3 2 ,反应体系水的质量分数为 2 0 % ,反应温度为 6 6℃ ,反应时间为 3 7h。当CH2 ClCOOH与淀粉摩尔比为 0 4时 ,取代度可达 0 35。     

干法制备天然阳离子壳聚糖的条件优化

研究中发现,壳聚糖可与缩水甘油氯化铵干法合成阳离子壳聚糖,文中讨论了反应物摩尔比、NaOH用量、反应温度和反应时间等因素对反应的影响,用正交试验确定了最佳反应条件。采用化学分析法和IR图谱对阳离子壳聚糖进行了表征。结果表明,当壳聚糖与阳离子化试剂的摩尔比为1∶3,NaOH与壳聚糖摩尔比为1∶2 5 ,最佳反应条件为时间3h ,反应温度80℃,阳离子壳聚糖得率为92 % ,季铵化度为95 %。     

酸催化剂制备白糊精工艺

以玉米淀粉为原料,干法制备白糊精。通过单因素实验,确定出影响白糊精溶解度的各因素为:浓盐酸量占淀粉质量的比例、反应温度、体系含水量、反应时间。在所进行的L9(34)四因素三水平白糊精正交实验中,确定出制备白糊精的最佳工艺参数为:体系含水量为22%,反应温度130℃,反应时间3h,浓盐酸量占淀粉质量的比例为0.25%。     

半干法制备高取代度阳离子淀粉及表征

以玉米淀粉为原料,利用N-(2,3- 环氧丙基)三甲基氧化铵(GTA)为醚化剂,在NaOH 为催化剂条件下,通过半干法制备阳离子淀粉。实验表明：对阳离子淀粉取代度(DS)影响的因素顺序依次为：反应时间＞反应温度＞体系中含水量＞氢氧化钠用量。当淀粉用量为10g、GTA 用量为1.5g、NaOH 0.2g、反应温度80℃、反应时间4h、体系中含水量24% 时,DS 可达到0.105。对不同取代度的阳离子淀粉进行理化性质分析及表征,结果表明：阳离子淀粉的透明度、溶解度均随着取代度的增高有所增加。通过对阳离子淀粉进行红外光谱、偏光分析和X 射线衍射分析,证实取代反应过程中淀粉结构发生了一定程度的变化。     

半干法制备阳离子淀粉的工艺优化

以玉米淀粉为原料,3-氯-2-羟丙基三甲基氯化铵(CTA)为醚化剂,在碱性条件下,采用半干法制备低取代度阳离子淀粉。采用Box-Behnken中心组合响应面设计,对半干法工艺进行优化,并分析反应温度、反应时间、碱的用量、体系含水量对阳离子淀粉取代度的影响。结果表明:回归方程能较好地预测取代度随工艺条件变化的规律,半干法制备低取代度阳离子淀粉工艺条件为:反应温度64.40℃,反应时间6.58 h,NaOH与醚化剂摩尔比2.12,体系含水量25.28%,在此条件下制得的阳离子淀粉取代度为0.051 9。     

新型干法工艺制备阳离子淀粉的研究

采用经过改装的挤压反应器作为干法反应装置,以玉米淀粉为原料,以3-氯-2-羟丙基氯化铵(CTA)为醚化剂制备阳离子淀粉。通过单因素试验研究了醚化剂添加量、NaOH添加量、含水量、挤压反应器温度、转速等因素对取代度和反应效率的影响;通过正交试验确定出新型干法制备阳离子淀粉的最佳工艺参数为:醚化剂添加量为5%,NaOH与醚化剂物质的量比为2∶1,水分含量为20%,挤压反应器温度为130℃,转速为400 r/min。研究结果表明,采用改进后挤压反应器制备阳离子淀粉是一种高效、连续、节能的新型干法工艺。     

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