紫甘薯水溶性多糖的提取工艺优化及结构研究

以紫甘薯为原材料,采用单因素和响应面试验对紫甘薯水溶性多糖的提取条件进行工艺优化,确定最佳提取率的工艺参数。采用Sepharose 4B凝胶对紫甘薯多糖进行分离纯化,并对纯化组分进行紫外扫描、红外光谱和单糖组成分析。结果表明,紫甘薯多糖提取的最佳条件：提取时间2.5 h、提取温度80℃和液料比15∶1（mL/g）,提取率可达到9.03%。多糖经分离纯化后,得到分子量为2.63×103kDa的均一多糖（purple sweet potato polysaccharide,PSPP-A）。紫外吸收图谱显示PSPP-A在260 nm和280 nm处均无吸收峰,说明不含核酸和蛋白质。红外光谱检测到PSPP-A具有多糖的特征吸收峰,离子色谱分析显示PSPP-A由5种单糖构成,分别为鼠李糖、阿拉伯糖、半乳糖、葡萄糖和葡萄糖醛酸,且摩尔比为 1.89∶8.45∶1.95∶1.13∶1。     

武夷岩茶“黄片”茶多糖的提取工艺优化及其理化性质分析

为提高武夷岩茶"黄片"茶多糖的提取率及分析其纯化后的理化性质,以茶多糖提取率为响应值,运用响应面法优化"黄片"茶多糖的提取工艺参数,并通过生化分析及红外光谱研究去蛋白纯化后的茶多糖理化性质。结果表明,"黄片"茶多糖最佳提取工艺为提取时间30.29 min、温度为71.15℃、料液比为1:25,在此条件下,茶多糖提取率的理论值为8.45%。经过纯化后的茶多糖还原糖、中性糖、蛋白质和糖醛酸质量分数分别为12.37%、18.99%、9.563%和6.358%;对茶多糖进行红外光谱分析,发现存在糖类及蛋白质的吸收峰,表明武夷岩茶"黄片"茶多糖是一种结构复杂的糖蛋白。     

超声结合酶法辅助提取甘蔗渣中水溶性多糖的工艺优化

该文以甘蔗渣为原材料,采用单因素试验和正交试验对甘蔗渣中水溶性多糖的提取条件进行优化,然后对其进行紫外吸收扫描和红外光谱分析。先用果胶酶、纤维素酶、中性蛋白酶逐个进行试验,比较提取率,结果表明,纤维素酶提取率最高。以纤维素酶作为辅助酶结合超声进行优化试验,结合极差分析和方差分析得到最佳优化工艺条件：料液比1∶30（g/mL）,酶解pH5.0,纤维素酶添加量为底物的4.5%,超声酶解时间60 min,超声酶解温度55℃,超声功率350 W,平均提取率为12.78%,比优化之前提取率高16.78%。紫外吸收图谱显示在波长260 nm～280 nm无特征吸收峰,即多糖中不含核酸和蛋白质,通过红外光谱检测官能团的伸缩振动峰图谱表明提取物质符合多糖的基本特征,进一步说明该提取工艺的可靠性。     

超声辅助酶法提取山药皮水溶性多糖的工艺优化

以铁棍山药皮为原材料,采用单因素试验和正交试验对山药皮中水溶性多糖的提取条件进行优化,后对其进行紫外吸收扫描和红外光谱分析。先用果胶酶、纤维素酶、中性蛋白酶进行辅助提取,结果表明,纤维素酶的提取率最高。以纤维素酶作为辅助酶结合超声进行优化试验,通过极差和方差分析,得到最佳优化工艺条件：纤维素酶加酶量5.0%、超声功率350 W、酶解-超声时间60 min,料液比1∶50（g/mL）,该条件下提取率为10.98%。紫外吸收图谱显示,在波长260 nm～280 nm无特征吸收峰,即山药皮粗多糖中不含核酸和蛋白质,通过红外光谱检测官能团的伸缩振动峰图谱表明,提取物质符合多糖的基本特征。     

微波辅助双水相提取百合多糖的工艺优化及其结构表征

为高效获取百合多糖和表征多糖结构，本文采用微波辅助双水相提取百合多糖，通过单因素实验和正交试验确定最佳的提取工艺；依次通过DEAE-52和Sephadex G-100柱色谱法纯化百合多糖粗提物，获得单一多糖馏分（LP2-SG），同时利用高效凝胶渗透色谱和气相色谱法分别测定LP2-SG的分子量和单糖组成，并对其结构进行初步表征。结果表明微波辅助双水相提取百合多糖的最优工艺为：微波功率400 W、硫酸铵质量分数20%和乙醇体积分数50%和料液比1:30 g/mL，百合多糖得率为10.15%±0.11%。纯化后的多糖馏分（LP2-SG）分子量为530.51 kDa，单糖组成为甘露糖、葡萄糖和半乳糖组成，其摩尔比为11.63:29.85:8.46。LP2-SG在260 nm和280 nm处无特征吸收，并具有典型的多糖红外光谱吸收特性。本研究结果为百合多糖的高效提取和深度开发提供重要参考。     

正交实验法优化牛鼻软骨中硫酸软骨素的醇沉工艺

研究牛鼻软骨碱提液中硫酸软骨素的醇沉工艺。通过单因素和正交实验对醇沉工艺进行优化,确定的最佳条件是:乙醇浓度65%,乙酸钠浓度4.5%,pH6.0。在该条件下,提取率为14.81%,葡萄糖醛酸含量33.36%,硫酸软骨素纯度达85.9%。紫外光谱分析:样品在196nm处有多糖的吸收峰,未见蛋白质(280nm)与核酸(260nm)的特征吸收峰。     

牛鼻软骨粉中硫酸软骨素的碱法提取及光谱分析

以牛鼻软骨为原料酶法制备软骨粉,采用稀碱液浸提和乙醇沉淀的方法提取硫酸软骨素(Chondroitin Sulfate,ChS),通过单因素和正交试验对碱解工艺进行优化,确定的最佳条件是:料水比1:6,NaOH浓度5%,温度40℃,浸提时间6h,在此条件下,提取率达到12.58%,葡萄糖醛酸含量为32.44%,硫酸软骨素纯度达82%。紫外光谱分析:样品在196nm处有多糖的吸收峰,未见蛋白质(280nm)与核酸(260nm)的特征吸收峰;红外光谱分析发现为典型的硫酸软骨素A吸收峰。     

超声波辅助法优化马齿苋多糖的提取工艺

多糖是马齿苋的主要生物活性成分之一,具有重要的医疗保健作用,市场潜力大。为确定马齿苋多糖的最佳提取工艺,通过单因素试验与响应面法对其提取工艺进行优化。结果表明,马齿苋多糖的最佳提取条件为:提取功率120 W,提取时间53 min,提取温度61℃,料液比1∶39(g/m L),马齿苋多糖提取率为13.55%。     

响应面优化木立芦荟皮多糖的研究

采用响应面分析法对木立芦荟皮多糖的提取工艺进行优化,对提取率影响因素进行单因素分析后,以BoxBehnken设计评价微波时间、提取液p H和液料比3个因素显著性和交互作用,最终得出木立芦荟皮多糖的最佳提取条件为:微波时间为168 s,提取液的p H为9,液料比为52∶1(m L/g),微波功率为320 W,在此条件下提取率为14.37%;并对提取的粗多糖进行红外光谱分析,结果表明木立芦荟皮粗多糖具有多糖的特征吸收峰。     

仙人掌多糖的提取及其结构初步研究

优化米邦塔仙人掌多糖提取工艺，并对其结构初步鉴别，以提取温度、提取时间、水料比为自变量，仙人掌多糖得率为响应值。利用Box—Benhnken中心组合试验优化提取工艺，采用DEAE Sepharose CL-6B纯化及红外光谱鉴别其多糖。结果表明：仙人掌多糖水提的最佳提取工艺条件为：提取温度86．1℃、提取时间3．61h、水料比3．72：1。仙人掌多糖的得率达到理论值0．694％，经DEAE Sepharose CL-6B纯化得3种多糖ASP1、ASP2、ASP3，得率分别为11．59％、45．21％和20．48％。红外光谱显示其具有多糖特征吸收峰。     

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.