响应曲面法优化黄秋葵花总黄酮的提取工艺

为提高黄秋葵花总黄酮的提取率,利用响应曲面法优化了黄秋葵花总黄酮的回流提取工艺。在乙醇浓度、提取温度、料液比、提取时间共4个单因素试验的基础上,采用Box-Behnken design方法进行四因素三水平试验,以总黄酮提取率为响应值,通过响应面分析得到二次多项式回归方程的预测模型。结果表明:料夜比对黄秋葵花总黄酮提取率的影响达到极显著水平(P0.01),乙醇浓度与提取温度对提取率的影响达到显著水平(P0.05),四因素对总黄酮提取率的影响作用大小依次为:料液比提取温度乙醇浓度提取时间。黄秋葵花总黄酮提取的最佳工艺条件为乙醇浓度40%,提取温度60℃,料液比1∶160(g∶mL),提取时间30min。黄秋葵花总黄酮提取率预测值为28.72mg/g,验证后提取率为27.98mg/g,与预测值基本吻合,相对误差为2.58%。     

微波辅助提取红松松针总黄酮工艺优化

研究以红松松针为主要原料提取总黄酮的最佳工艺。通过单因素试验、正交试验确定了红松松针总黄酮的最佳提取工艺条件为:红松松针总黄酮最佳的提取工艺条件为乙醇浓度为80%、提取温度80℃、提取时间为2 h、固液比1∶20(g/m L),微波功率600 W,处理时间5 min,通过方差分析确定固液比是影响红松松针粗黄酮提取率的显著因素,在此条件下的红松松针总黄酮提取率可达3.37%。     

黑木耳总黄酮的超声辅助提取

为了优化超声辅助提取黑木耳总黄酮的工艺条件,提高黑木耳总黄酮的提取率,本文通过单因素试验和正交试验,考察固液比、超声功率、超声时间和乙醇浓度四个因素对黑木耳总黄酮提取率的影响。结果显示最佳提取条件为:固液比1∶6、超声功率80W、超声时间15min、乙醇浓度80%,黑木耳总黄酮提取率达到0.79%。超声辅助提取增加了黑木耳总黄酮的提取率,为黑木耳的开发和药理研究提供了依据。     

微波辅助提取桃金娘果实总黄酮的研究

通过单因素试验研究了微波功率、微波时间、乙醇浓度、液固比等因素对桃金娘果实总黄酮提取率的影响,利用正交试验法对提取工艺进行优化。结果表明,各因素对桃金娘总黄酮提取率的影响次序为液固比微波功率微波时间,最佳提取工艺条件为微波功率300W、微波时间5min、液固比25∶1,乙醇浓度40%vol。     

超声波辅助提取无花果叶中总黄酮工艺的研究

通过单因素试验和正交试验确定超声波辅助法提取无花果叶中总黄酮的优化工艺。结果表明:提取时间和料液比对总黄酮提取率有显著影响(P≤0.05),最佳工艺条件为:乙醇浓度为40%、提取时间为9 min、料液比为1∶40(g/mL),在此条件下总黄酮的得率为3.249%。     

超声波辅助提取荷花粉总黄酮工艺优化研究

采用超声波辅助提取荷花粉中的总黄酮,利用单因素试验和响应面方法优化总黄酮的最佳提取工艺,研究液固比、乙醇浓度、超声处理温度和提取时间对总黄酮提取率的影响。结果表明,当超声波功率250 W条件下,超声波辅助提取荷花粉总黄酮最佳工艺参数为液固比18.5(m L/g),乙醇浓度82%,提取温度74℃,提取时间53 min,总黄酮的提取率可达1.658 2%。     

蝴蝶荚蒾花中总黄酮提取工艺研究

以蝴蝶荚蒾花为试验材料,研究蝴蝶荚蒾花中总黄酮类色素的提取工艺。通过单因素试验和正交试验,研究不同固液比、乙醇浓度、提取温度和提取时间对黄酮提取率的影响。试验结果表明:最佳提取工艺参数为固液比1∶25(g/mL)、乙醇浓度40%、提取温度60℃、时间10 min。在此条件下,蝴蝶荚蒾花总黄酮的提取率为9.23%。     

迷迭香总黄酮的提取工艺

研究迷迭香中总黄酮的最佳提取工艺。采用单因素试验和正交试验考察乙醇浓度、料液比、提取时间和提取温度对总黄酮提取率的影响。结果表明,迷迭香总黄酮最佳提取工艺条件为：乙醇浓度50%,料液比1∶20（g/mL）,提取时间4 h,提取温度90℃,在此条件下总黄酮提取率达6.31%。     

紫苏叶中总黄酮的超声波辅助提取工艺优化

以总黄酮提取率为指标,通过单因素试验考察液料比、超声时间、乙醇浓度、提取温度对紫苏叶总黄酮提取率的影响,采用响应面分析法对超声波辅助乙醇提取紫苏叶中总黄酮的工艺进行优化。结果表明,紫苏叶总黄酮最佳提取条件为:液料比29∶1(V∶m)、超声时间40min、乙醇浓度45%、提取温度51℃,该条件下紫苏叶中总黄酮的实际提取率为5.41%。     

响应面法优化超声波-微波协同提取黑果枸杞叶总黄酮工艺

利用响应面法对超声波-微波协同提取黑果枸杞叶总黄酮的工艺进行优化,在单因素试验基础上,以微波功率、液料比、提取时间、乙醇浓度为主要因素,总黄酮提取率为响应值,通过响应面分析法进行四因素三水平BoxBehnken试验对提取条件进行优化。结果显示,各因素对黑果枸杞叶总黄酮提取率相对影响程度为:液料比乙醇浓度提取时间微波功率。且液料比18.9∶1(mL/g),乙醇浓度69%,提取时间9.9 min,微波功率175 W为最佳提取条件,此时黑果枸杞叶总黄酮提取率为(0.997±0.015)%。理论预测值为1.01%,结果与预测值基本符合,证明该模型有效,工艺稳定可行。     

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