微波辅助法提取野生软枣猕猴桃茎黄酮的工艺优化

研究了微波辅助法提取野生软枣猕猴桃茎黄酮类化合物的工艺条件。通过单因素实验分别考察微波功率、提取时间、乙醇浓度、料液比对黄酮提取率的影响,以软枣猕猴桃茎黄酮的提取率为指标,根据单因素实验结果设计正交实验,得出微波辅助法提取的最佳工艺条件：微波功率为300W,乙醇浓度为70%,料液比为1∶32,提取时间为5min,此条件下软枣猕猴桃茎黄酮提取率为1.80%。     

微波萃取在菊花黄酮提取工艺中的应用研究

在微波单因素提取的基础上采取L9(34)正交优化试验,探讨乙醇浓度、微波提取时间和料液比对菊花黄酮提取率的影响.经过单因素试验及正交试验,结果表明:影响菊花黄酮微波提取的主要因素为乙醇浓度,其次为提取时间、料液比.在微波功率300 W的条件下,最佳提取工艺条件为乙醇浓度60%,提取时间120 s,料液比1∶20.此时总黄酮提取率为4.83%.     

微波辅助双水相提取菠萝皮中黄酮的研究

采用微波辅助乙醇-磷酸氢二钾双水相的方法对菠萝皮中黄酮进行提取,探讨了乙醇浓度、提取时间、微波功率、磷酸氢二钾用量和液料比等因素对黄酮提取的影响,并采用正交实验法进行优化。实验结果表明:最佳提取工艺为乙醇浓度为60％,提取时间为45 s,微波功率为464 W,液料比为40:1 (mL·g-1),在此条件下,黄酮得率可达5.34%。研究结果可为废弃资源的综合开发利用提供科学依据。     

微波法提取西南委陵菜黄酮及其抗氧化活性的细胞模型法评价

利用微波法以乙醇作为提取剂提取了西南委陵菜黄酮,考察了乙醇浓度、料液比、提取温度、微波功率和提取时间对西南委陵菜黄酮提取得率的影响。结果表明,微波法提取西南委陵菜黄酮的最佳条件是乙醇浓度50%、料液比1∶30、提取温度60℃、微波功率400W、提取时间5min。黄酮的最佳得率为5.68%。西南委陵菜黄酮在结肠癌细胞HT-29和小鼠巨噬细胞RAW264.7两种细胞中表现出明显的抗氧化活性,其抗氧化性随浓度增加递增。     

仙人掌黄酮微波法提取工艺响应面优化

仙人掌黄酮类化合物作为一种多酚类物质,具有广泛的生物活性和药理活性。随着食品及化妆品工业的发展与消费观念的改变,黄酮类化合物以纯天然、高活性、见效快、作用广泛等特点日益受到人们的关注。仙人掌黄酮的提取工艺以乙醇为溶剂采用微波法辅助提取。本实验首先分析微波功率、微波时间、乙醇浓度、液料比等单因素对黄酮得率的影响,随后用响应面软件对微波法提取仙人掌中黄酮提取工艺进行优化。结果表明:对于得率的影响程度为液料比提取功率乙醇浓度提取时间。利用响应曲面分析进行回归预测和优化后,仙人掌黄酮得率的最大预测值0.855%,此时的提取条件为:提取时间2.55min,液料比34∶1,乙醇浓度96.5%,超声功率310.6W。经过验证实验得到的提取率为0.832%,与预测值相差2.69%,在可接受范围内。     

响应面法优化微波辅助提取艾草黄酮工艺

以艾草为原料,通过单因素试验和响应面试验设计优化微波辅助提取黄酮工艺,分别考察了乙醇浓度、液料比、微波功率、微波时间对黄酮得率的影响。结果表明,最优工艺条件为:乙醇浓度72%、液料比45∶1(g/m L),微波功率520 W,微波时间151 s,在此工艺条件下,艾草黄酮得率为4.37%。     

微波技术在杜仲黄酮提取工艺中的应用研究

本文在微波单因素浸提的基础上,采取L9(34)正交优化试验,以探讨微波功率、乙醇浓度、料液比和提取时间对杜仲黄酮提取率的影响研究。单因素试验结果表明:最佳萃取工艺参数为,微波功率200W,乙醇浓度为50%,液料比为1:30,提取时间10min。正交试验结果表明:影响杜仲微波浸提的主要因素为乙醇浓度,其次是提取时间、料液比、微波功率。最佳提取工艺条件为为A2B3C2D3,即乙醇浓度50%,提取时间25min,料液比1:30,微波功率400W。此时总黄酮含量为0.7672%。     

响应曲面法优化千年健黄酮的提取工艺

单因素实验研究了微波时间、微波功率、乙醇浓度和液固比对千年健黄酮提取率的影响,利用响应面法对提取工艺进行优化,用Design-Expert 7.0软件对实验数据进行二次响应面分析。结果表明:各因素对黄酮提取率影响的次序为液固比微波功率乙醇浓度微波时间,最佳提取工艺条件为:微波功率273.8 W、微波时间5min、乙醇浓度50%、液固比30∶1(mL/g),在此条件下提取率为0.5881%。     

银杏愈伤组织黄酮提取条件的正交实验优化

以银杏愈伤组织为材料,对银杏黄酮的提取条件进行优化。通过单因素实验研究乙醇浓度、液料比、微波功率、微波时间、水浴温度、水浴时间等对黄酮得率的影响,并进行了正交实验优化。正交实验的结果表明:以40%乙醇为提取溶剂,液料比25∶1,在中火档(528W)微波60s,不进行水浴处理,黄酮得率达到20.92mg/g。     

三叶委陵菜黄酮的微波辅助提取工艺研究

研究三叶委陵菜中黄酮类物质的微波辅助提取工艺,采用微波辅助提取法提取了三叶委陵菜黄酮,考察乙醇浓度、微波功率、提取时间、回流温度、料液比对三叶委陵菜提取液中黄酮含量的影响,确定了微波萃取仪提取三叶委陵菜黄酮的最佳工艺条件为:以75%乙醇作溶剂,在料液比为1∶25(g/mL),温度70℃,功率400 W的条件下微波提取5 min,效果最好,提取液中总黄酮含量为4.24%。     

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.