百合中水溶性非淀粉多糖的分离与纯化

百合中水溶性非淀粉多糖的提取、分离和纯化方法的研究表明 ,糊化淀粉经α 淀粉酶和普鲁兰酶水解除去后 ,剩余多糖经SepharoseCL 6B与SephedexG 10 0凝胶过滤色谱分离 ,得到比浓粘度为 81.2 92cm3/ g的水溶性非淀粉多糖 ,其相对分子质量较小 (2 0 0 18.6 ) .研究中还发现一些多糖与蛋白质以结合形式糖蛋白存在 .     

灰树花胞外多糖的性质与结构

对发酵法生产的灰树花胞外多糖GLP A 2的理化特性与结构进行了初步研究 .经凝胶柱层析和HPLC检测纯度 ,证明水溶性多糖GLP A 2为单一均匀组分 ,不含蛋白质和核酸 ,比旋光度[α]12D =+ 177.5 0°(H2 O ,0 .1) ,HPLC法测得平均相对分子质量为 6 .2× 10 4 .GC、IR和13C NMR分析表明 ,GLP A 2是一类 β 葡聚糖 ,分子的主链以 β (1→ 3) 糖苷键连接 ,并含有 β (1→ 6 )、α (1→2 )、α (1→ 3)及 β (1→ 2 )糖苷键相连的侧链 .GLP A 2可与刚果红结合 ,形成的络合物在 0～ 0 .4mol/L的NaOH溶液中 ,表现出最大吸收波长 (λmax)的特征变化 ,同时在CD谱中出现明显的有序结构信息 .这提示GLP A 2在溶液中存在三股螺旋构象 ,维持其有序构象的力可能以氢键力为主     

甘薯多糖SPPS-I-Fr-II组分的结构与抗肿瘤活性

甘薯多糖组分SPPS -I-Fr-II纯品 ,经甲基化分析 ,高碘酸氧化 ,Smith降解 ,1H、13 CNMR及IR等对其化学结构研究表明SPPS -I-Fr -II是由α -D -Glcp以 1,6糖苷键形成的一种葡聚糖。小鼠移植性实体瘤研究表明SPPS -I-Fr -II对移植性黑色素B16和Lewis肺癌有很强的抑制作用     

山药多糖RDPS-I组分的纯化及理化性质的研究

山药经水浸提分离 ,浸提液脱蛋白 ,透析 ,乙醇沉淀物经DEAE -5 2纤维素及SephadexG -10 0色谱纯化得白色粉末状多糖RDPS -I。SepharoseCL -6B凝胶色谱分析表明RDPS -I为多糖纯品。定性化学反应表明RDPS -I不含核酸、蛋白质、酚类物质和糖醛酸 ,是一种非淀粉类中性纯粹多糖 ,比旋光度 [α] 2 2D(H2 O)为 +188 4(c =0 8) ,特性粘度 [η]为 16 48× 10 -3 (mL/g) ,相对分子质量为 42 2 0 0 ,完全酸水解后纸层析及气相色谱分析确定RDPS -I的糖基组成为葡萄糖、甘露糖和半乳糖 ,摩尔比为 1∶0 37∶0 11。     

甘薯多糖SPPS-Ⅰ-Fr-Ⅱ组分的纯化及理化性质分析

甘薯经水浸提,Sevag法脱蛋白,透析,乙醇沉淀,DEAE-纤维素及Sephadex G-100色谱分离纯化得到一种白色粉末状多糖SPPS-Ⅰ-Fr-Ⅱ.经SepharoseCL-6B凝胶色谱分析证明SPPS-Ⅰ-Fr-Ⅱ为纯品.经定性化学反应鉴定表明SPPS-Ⅰ-Fr-Ⅱ不含蛋白质、核酸、酚类物质和糖醛酸,为非淀粉类中性纯粹多糖.其比旋光度[α]22D(H2O)为+115.0(c=0.8),特性粘度[η]为17.23×10-3(mL@g-1),重均分子量为53200.SPPS-Ⅰ-Fr-Ⅱ完全酸水解后纸层析及气相色谱分析确定糖基组成为葡萄糖.     

甘薯多糖SPPS-I-Fr-Ⅱ组分的结构与抗肿瘤活性

甘薯多糖组分SPPS-Ⅰ-Fr-Ⅱ纯品，经甲基化分析，高碘酸氧化，Smith降解，1H、13CNMR及IR等对其化学结构研究表明SPPS-Ⅰ-Fr-Ⅱ是由α-D-Glcp以1，6糖苷键形成的一种葡聚糖。小鼠移植性实体瘤研究表明SPPS-Ⅰ-Fr-Ⅱ对移植性黑色素B16和Lewis肺癌有很强的抑制作用。     

甘薯多糖SPPS-I-Fr-Ⅱ组分的纯化及理化性质分析

甘薯经水浸提,Sevag法脱蛋白,透析,乙醇沉淀,DEAE-纤维素及Sephadex G-100色谱分离纯化得到一种白色粉末状多糖SPPS-I-Fr-Ⅱ。经Sepharose CL-6B凝胶色谱分析证明SPPS-I-Fr-Ⅱ为纯品。经定性化学反应鉴定表明SPPS-I-Fr-Ⅱ不含蛋白质、核酸、酚类物质和糖醛酸,为非淀粉类中性纯粹多糖。其比旋光度[α]D22(H2O)为+115.0(c=0.8),特性粘度[η]为17.23×10-3(mL·g-1),重均分子量为53200。SPPS-I-Fr-Ⅱ完全酸水解后纸层析及气相色谱分析确定糖基组成为葡萄糖。     

山药多糖RDPS-Ⅰ组分的纯化及理化性质的研究

山药经水浸提分离,浸提液脱蛋白,透析,乙醇沉淀物经DEAE-52纤维素及Sephdex G-100色谱纯化得白色粉末状多糖RDPS-I.Sepharose CL-6B凝胶色谱分析表明RDPS-I为多糖纯品.定性化学反应表明RDPS-I不含核酸、蛋白质、酚类物质和糖醛酸,是一种非淀粉类中性纯粹多糖,比旋光度[α]22 D(H2O)为+188.4(c=0.8),特性粘度[η]为16.48×103(mL/g),相对分子质量为42 200,完全酸水解后纸层析及气相色谱分析确定RDPS-I的糖基组成为葡萄糖、甘露糖和半乳糖,摩尔比为10.370.11.     

关于短区间中D.H.Lehmer问题的一个推广

利用不完全Kloosterman和的均值定理研究短区间中的D.H.Lehmer问题,并且给出了渐近公式.设p是奇素数,H>0,K>0,并设I(j)1,I(j)2是(0,p)的子区间,1≤j≤J,满足|I(j)1|=H,|I(j)2|=K,以及I(j)1∩I(k)1=Ф.当j≠k时,证明J∑(J=1)∑x∈I(j)1∑y∈I(j)2xy≡1(modp)2(x+y)=JHK/2p+O(J1/2p1/2logHlogp).     

九州虫草菌丝体多糖Ck_3-A的分离纯化及其理化性质研究

以九州虫草 (Cordycepskyushuensis Kobayasi)发酵菌丝体为试验材料 ,采用水提法得到九州虫草菌丝体粗多糖。粗多糖经酶法结合Sevag法除蛋白、H2 O2 法脱色、透析、分级沉淀得到Ck3 ,Ck3 经DE 2 3柱层析得到多糖Ck3 A。经紫外扫描、聚丙烯酰胺凝胶电泳、Sepharose 4B柱层析等方法检测确定Ck3 A为均一组分。用苯酚 硫酸法测得Ck3 A的含糖量为 73 1% ,硫酸 咔唑法测得Ck3 A含有微量的葡萄糖醛酸。Sepharose 4B柱层析测得Ck3 A的分子量为 92 5 0 0u。红外光谱结果显示Ck3 A含有α 型糖苷键。     

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