离子交换吸附分离茶氨酸的研究

本实验以目前工业上生产茶多酚后的废茶水为原料,通过超滤、脱色等预处理后,通过离子交换树脂对茶氨酸进行吸附分离,探索从其中分离制备茶氨酸的工艺。选用001×7阳离子交换树脂,分析了影响茶氨酸交换容量的因素,并对树脂吸附茶氨酸的动力学进行了研究。通过响应面分析法确定固定床离子交换工艺中合适的吸附工艺条件为:pH值为3.4,上样液浓度为3.0mg/ml,上样流速为1.7柱床体积/h。最后确定洗脱工艺条件,用pH11.3的氨水洗脱后得到茶氨酸含量为58%,离子交换过程中茶氨酸的回收率为82%。     

利用D-900树脂对巴戟天多糖脱色工艺进行优化

研究D-900阴离子交换树脂对巴戟天多糖的最佳脱色工艺。采用D-900阴离子交换树脂对巴戟天多糖进行静态和动态吸附试验,考察不同温度、树脂用量、流速和pH值等因素对吸附过程的影响,以脱色率和多糖保留率综合评价其脱色效果。最佳工艺参数为：采用动态吸附,柱溶液温度45℃、流速1.0BV/h、上样液pH6.0。使用D-900阴离子交换树脂对巴戟天多糖脱色可以获得较好的脱色率以及较高的多糖保留率。     

大孔树脂对甜茶溶液脱色的研究

以脱色率和甜茶甙的保留率作为考察指标,对9种树脂进行了筛选,并通过静态吸附试验和动态的单因素试验对筛选出的树脂的最佳脱色条件和再生条件进行了研究。结果表明:D296阴离子交换树脂的脱色效果最好,其最佳脱色条件为:上柱液p H6.5,流速2.0 BV/h,上样浓度(以多酚浓度计)3.0 mg/m L。最佳再生条件为:用3%的Na OH和HCl溶液先后冲洗树脂至流出液近无色。     

大孔树脂对溪黄草多酚吸附分离的工艺优化

以溪黄草多酚为原料,通过静态吸附和解吸实验对10种大孔树脂进行筛选,确定AL-1为最优吸附树脂。通过静态与动态相结合的方法,确立AL-1树脂对溪黄草多酚的最佳吸附/解吸工艺条件。结果表明,溪黄草多酚提取液的最佳吸附条件为:上样总酚质量浓度为520μg/mL,上样液pH为4,吸附流速为0.8mL/min;最佳洗脱条件为:乙醇体积分数80%,流速0.5mL/min。     

苹果汁中果酸(苹果酸)的分离(Ⅰ)--果酸在LSI-1031阴离子交换树脂上交换吸附行为的研究

研究了苹果汁中果酸在4种阴离子交换树脂上的静态吸附特性,其中LSI-1031阴离子交换树脂对果酸的交换吸附能力最强;系统测定并分析了果酸在LSI-1031阴离子交换树脂上交换吸附静态动力学、吸附等温曲线、动态动力学曲线及影响动态动力学曲线的因素,并确定了果酸交换吸附最佳工艺参数,结果表明:LSI-1031阴离子交换树脂吸附平衡时间为4h;20℃时,LSI-1031阴离子交换树脂吸附等温曲线符合Langmuir型吸附曲线;柱操作流速、果汁中果酸浓度以及温度对LSI-1031阴离子交换树脂动态动力学曲线都有影响,柱处理最佳条件为:流速3BV/h、温度50℃,并且低果酸浓度的果汁有利于提高树脂的处理量。     

离子交换树脂对马尾松松针中草酸的分离纯化

比较4种吸附树脂对马尾松松针提取液中莽草酸的静态吸附和解吸效果,从中筛选出适合该提取液中莽草酸分离纯化的树脂,并对其动态吸附-解吸性能进行研究.结果表明,331阴离子交换树脂最适合马尾松松针提取液中莽草酸的纯化.当上样液的质量浓度为1.5mg/mL,上样流速为2mL/min,上样液体积为4BV时,331阴离子交换树脂达到动态吸附饱和.再用8BV 2％的氢氧化钠溶液,以4mL/min的流速可以完全洗脱.经过331阴离子交换树脂的纯化,莽草酸的纯度由原来的25％提高到90％,纯化提取率为90.9％.     

树脂柱色谱纯化甘油磷脂酰胆碱

研究了树脂柱色谱纯化甘油磷脂酰胆碱(L-α- GPC)的可行性,通过树脂筛选,确定D001大孔阳离子交换树脂为最佳纯化树脂,并对纯化工艺条件进行了优化.通过静态实验得到最优条件:上样质量浓度1.52 mg/mL,样品溶液pH为7,吸附时间300 min,解吸液为去离子水.在静态实验的基础上,进行了树脂柱色谱纯化L-α - GPC的动态实验,对吸附流速、解吸液和解吸流速进行优化.动态实验最优条件:吸附流速2 mL/min,解吸液为去离子水,解吸流速2 mL/min.依据动态实验最优条件,最终L -α- GPC的纯度为96％,回收率为54.1％,这表明树脂柱色谱纯化L-α - GPC的方法是经济、方便、可行的.     

离子交换树脂分离合成茶氨酸

采用离子交换树脂法取代常规的醇沉法分离、纯化合成的茶氨酸粗品。以732型阳离子交换树脂为分离材料,探讨了上样浓度、洗脱液浓度、pH对茶氨酸分离效果的影响,比较离子交换法和乙醇沉淀法对合成茶氨酸粗品的分离效果。结果表明:上样液中茶氨酸的最佳质量浓度为4mg/mL,最佳洗脱液(氨水)浓度为0.4mol/L,茶氨酸在pH=8～11时被解吸。当茶氨酸纯品进样量为200mg,流速为1mL/min,完全洗脱茶氨酸时,约需0.4mol/L氨水50mL,即需0.25mL0.4mol/L氨水/mg茶氨酸。当产品质量分数相近且≥95%时,离子交换法比乙醇沉淀法的产率高25%以上。使用阳离子交换树脂分离合成茶氨酸,大大提高了产品的纯度和得率。     

树脂法分离纯化桑葚花色苷

分别对12种大孔吸附树脂和6种阳离子交换树脂对桑葚花色苷的吸附性能进行了比较,通过静态吸附和解吸实验筛选出最佳大孔吸附树脂为LX-68,最佳阳离子交换树脂为D001。分别对这2种树脂进行静态和动态条件优化,确定了LX-68树脂最佳纯化条件为:以吸光度值0.991,pH值为3的色素液,8BV/h上样,用pH值为2、体积分数为80%的酸性乙醇作洗脱剂,洗脱流速为1BV/h,纯化后色素色价为114,纯度为39.9%,花色苷收率为91.5%。D001树脂最佳纯化条件为:以吸光度1.411Abs,pH值为2的色素液,6BV/h上样,用pH值为1、60%的酸性乙醇以3BV/h的洗脱流速洗脱,得到色价为65的色素粉末产品,纯度为24.1%,花色苷收率为67.6%。LX-68树脂和D001树脂对桑葚花色苷均具有较好的吸附分离性能,且LX-68树脂的分离效果优于D001树脂。     

树脂柱层析法分离纯化籽瓜中L-瓜氨酸

目的:研究适合分离纯化籽瓜L-瓜氨酸的树脂柱层析方法。方法:选择001×7、D001和D061三种阳离子交换树脂进行L-瓜氨酸静态吸附解析和动态平衡实验,优化分离提纯籽瓜L-瓜氨酸工艺。通过考察温度、p H、浓度、吸附穿透曲线及洗脱液浓度、流速因素,进一步研究001×7树脂层析柱分离纯化籽瓜L-瓜氨酸的条件。测定三种不同极性大孔吸附树脂和活性炭对籽瓜提取液的脱色率和吸附率,优化脱色工艺。结果:分离提纯籽瓜L-瓜氨酸工艺用001×7型阳离子交换树脂较适合,最佳工艺条件:上柱温度为40~50℃,上柱液的p H为3,洗脱液选择0.5 mol/L的氨水,洗脱流速为0.5 m L/min,洗脱液的用量为6倍树脂体积。脱色工艺使用HZ-801大孔吸附树脂较合适,脱色精制后可得到纯度为96.6%的L-瓜氨酸产品。结论:001×7型阳离子交换树脂层析柱和HZ-801大孔吸附树脂相结合,可以有效分离纯化籽瓜中的L-瓜氨酸,对充分利用籽瓜资源和改变我国L-瓜氨酸成本较高现状具有十分重要的意义。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.