超临界CO2萃取阴香叶挥发油及GC-MS分析

采用超临界CO_2萃取阴香叶的挥发性成分。通过单因素和正交试验确定超临界CO_2萃取阴香叶片挥发油的最佳工艺条件:萃取压力20 MPa、温度45℃、萃取时间90 min。用气相色谱-质谱联用(GC-MS)结合计算机检索对其化学成分进行了分析和鉴定,并用气相色谱峰面积归一法测定各组分的相对百分含量。结果显示,从阴香叶挥发油中鉴定出了33种化合物,总计占总峰面积的92.69%,其主要成分为龙脑47.23%,α-松油醇2.12%,乙酸龙脑酯5.42%,香豆素13.20%,匙叶桉油烯醇3.17%,石竹烯氧化物2.88%,6,10,14-三甲基-2-十五烷酮2.58%。为进一步开发利用阴香资源提供了科学参考。     

超临界CO2萃取姜挥发油及GC-MS分析

正交试验法时超临界CO2提取生姜挥发油的提取条件进行研究.结果表明,最佳提取条件为:原料粒径为03mm,萃取压力25 MPa,温度40℃,CO2流量30 kg/h,萃取时间100min,所得姜精油呈浅黄色,得率由传统水蒸气蒸馏法的1%左右提高到4.38%.采用气相色谱-质谱联用技术测定最佳提取条件下所得生姜挥发油的化学成分及其相对质量分数,共分离出58种成分并鉴定出其中38种,主体呈香成分为柠檬烯、α-蒎烯、莰烯、金合欢烯、β-水芹烯、β-倍半水芹烯、姜烯等烯类.主体辣味成分为6-姜醇.     

前胡挥发油的超临界CO_2流体萃取及其成分分析

采用正交设计优化前胡中挥发油的萃取工艺条件,确定了超临界CO2萃取前胡挥发油的最佳条件:萃取压力35 MPa,萃取温度50℃,选择无水乙醇为夹带剂,夹带剂用量为20%,萃取时间为90 min,解析压力为7~8 MPa,解析温度为45℃,萃取率为37.58%。GC/MS法分析前胡油的主要成分为à-蒎烯、à-月桂烯、蒈烯、石竹烯等,质量分数约为76.32%。与传统提取方法相比,应用超临界萃取前胡油不仅简便、提取率高,而且得到的膏状萃取物香气纯正。     

响应面试验优化超临界CO2萃取人参挥发油的工艺

以生晒参为原料,响应面分析法优化超临界CO2提取挥发油的工艺。采用自动质谱退卷积定性系统和保留指数方法对挥发油化学成分定性。结果表明：最佳工艺条件为萃取压力38 MPa、萃取温度55 ℃、静态萃取时间2 h、动态萃取时间1 h,此条件下挥发油提取率达1.12%。气相色谱-质谱法结果显示分离出35 个色谱峰,鉴定出29 种化学成分,相对含量占挥发性物质的96.69%。     

二种方法提取紫苏挥发油的气相色谱-质谱比较

采用超临界CO2流萃取紫苏挥发油，对在不同条件下萃取的紫苏挥发油，用色谱-质谱（GC-MS）联用方法进行了化学组分的测定和分析，并与水蒸气蒸馏法所得之挥发油化学组分相比较，发现超临界CO2流萃取的挥发油香气、品质和产率均优于蒸馏法所得。     

超临界CO2萃取北五味子藤茎挥发油的GC-MS分析

采用超临界CO2萃取的方法提取北五味子藤茎中挥发油成分,测得其挥发油得率为0.43%,采用气相色谱-质谱(GC-MS)联用的方法对其化学成分进行分析,经计算机NIST02谱库检索及人工解析质谱,共鉴定出1S-α-蒎烯、莰烯、衣兰烯、五味子素等41种成分,并利用峰面积归一化法定量测定它们的相对含量。     

超临界CO2萃取桂花油的工艺研究

研究了用超临界CO2萃取方法提取桂花油的工艺条件，考察了萃取时间、温度、压力、夹带剂对桂花油收率的影响，并且借助气相色谱考察了采用不同夹带剂时所得桂花油成分的变化。结果表明，桂花萃取最佳工艺条件为：压力15MPa温度50℃，时间20min，采用水-乙醇混合夹带剂（含水40％）下桂花油的提取收率最高，收率可达1.07％，此时萃取了桂花中所含的各种极性的成分。     

超临界CO2萃取九叶青花椒和大红袍花椒挥发油的化学成分分析及香气比较

采用超临界CO2萃取法提取九叶青花椒和大红袍花椒挥发油,以气相色谱-质谱仪对其化学成分进行检测,用色谱峰面积归一化法确定各化学成分的相对含量,评香师对花椒挥发油的香气进行评价.结果表明,超临界萃取的九叶青花椒挥发油得率为7%,鉴定出63个化合物,属青香型花椒油;超临界萃取的大红袍花椒挥发油得率为4%,鉴定出80个化合物,属浓香型花椒油;两种花椒挥发油的化学成分含量和香气有明显差异,但都保留了各自品种的天然香气特征.     

超临界CO2萃取杜仲叶总黄酮的研究

本论文采用超临界CO2萃取技术萃取杜仲叶总黄酮,对萃取温度、时间、压力和夹带剂用量四因素进行研究,并采用紫外分光光度法对萃取物中的总黄酮进行定量分析。确定了超临界CO2萃取杜仲总黄酮的最佳工艺条件为:温度为45℃、时间为2.5h、压力为30MPa、夹带剂用量为3.5ml/g。黄酮提取率为73.26%,产品纯度为19.82%。     

超临界CO2萃取西瓜籽油的研究

采用超临界CO2流体萃取方法从西瓜籽中提取西瓜籽油.利用正交实验探讨萃取压力、萃取温度、萃取时间、夹带剂用量对西瓜籽油萃取率的影响.结果表明,影响西瓜籽油萃取率的因素主次顺序为:萃取压力>萃取时间>萃取温度> 夹带剂用量;最佳提取条件为萃取压力40 MPa,萃取温度45℃,萃取时间150 min,夹带剂乙醇用量7%.在最佳条件下西瓜籽油萃取率为52.18%.     

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