超声波提取炒王不留行总三萜的工艺优化及其抑菌活性研究

优化炒王不留行总三萜提取工艺,并分析其抑菌活性。在单因素实验的基础上,选取乙醇浓度、液料比、超声温度和超声时间为自变量,总三萜得率为响应值,采用4因素3水平的响应曲面分析法优化炒王不留行总三萜提取工艺;并采用倍比稀释法研究炒王不留行总三萜提取物对10种常见致病菌的抑菌作用。结果表明,超声波辅助提取炒王不留行总三萜最佳提取工艺条件为:乙醇浓度65%,料液比1:25(g/mL),超声温度63℃,超声时间40 min。在此工艺条件下,炒王不留行总三萜的得率为1.24%±0.003%,与模型预测值1.28%之间具有良好的拟合性。炒王不留行总三萜提取物对所选10种常见致病菌均有一定的抑制作用,尤其是对大肠杆菌、金黄色葡萄球菌、化脓性链球菌和肺炎链球菌抑制作用最强,其最小抑菌浓度(MIC)和最小杀菌浓度(MBC)均在1.25~5 mg/mL之间。该提取方法稳定、高效,可用于炒王不留行中总三萜的提取,同时提取物具有较强的广谱抗菌作用。     

超声波结合酶法提取艾叶总生物碱工艺优化及其抑菌活性

以艾叶总生物碱的提取量为指标,通过单因素实验得到料液比、复合酶添加量、酶解时间、酶解pH、超声时间、超声功率、乙醇浓度和超声温度的最佳范围条件,使用Plackett-Burman法筛选出对艾叶总生物碱的提取量影响较为显著的因素,再利用Box-Behnken法对提取工艺进行优化分析,得出最佳的提取工艺条件。最后,采用纸片法和稀释法测定艾叶总生物碱提取物对大肠杆菌和金黄色葡萄球菌的抑制效果与最小抑制浓度。结果表明,影响艾叶总生物碱提取量的显著因素为超声时间、复合酶添加量和酶解时间。最佳提取工艺条件为:超声时间40 min,复合酶添加量1.60%,酶解时间1.5 h,料液比1:25 g/mL,酶解pH6.0,超声功率160 W,乙醇浓度80%,超声温度60 ℃,总生物碱的提取量最高为0.720±0.05 mg/g。艾叶总生物碱对大肠杆菌和金黄色葡萄球菌有抑菌活性,其最低抑菌浓度分别为3.2、1.6 mg/mL。该提取工艺实际值与预测值拟合度较高,可用于艾叶总生物碱的提取,且得到的艾叶总生物碱具有一定的抑菌活性。     

山银花总三萜超声辅助提取工艺优化及其抗菌抗氧化活性研究

采用响应面法优化山银花总三萜提取工艺,并研究其抑菌和抗氧化活性。以总三萜得率为评价指标,在考察单因素试验的基础上,根据响应曲面分析法优化山银花总三萜提取工艺,并分别采用倍比稀释法和清除自由基法研究山银花总三萜提取物对10种常见致病菌的抑菌作用及抗氧化活性。结果表明:山银花总三萜最佳提取工艺条件为:乙醇浓度60%、料液比1:26（g/mL）、超声温度63℃、超声时间60 min。在此工艺条件下,山银花总三萜的得率为3.37%±0.02%,与模型预测值3.36%基本一致。山银花总三萜提取物对供试菌株均有不同程度的抑制,且对大肠杆菌、金黄色葡萄球菌、铜绿假单胞菌、化脓性链球菌和肺炎链球菌抑制作用最强,最小抑菌浓度（MIC）和最小杀菌浓度（MBC）均在12.5 mg/mL以下;且对DPPH和ABTS自由基具有较好的清除作用,清除效果与总三萜浓度呈剂量-效应关系。优化后的山银花总三萜超声辅助提取工艺稳定可行,且其具有较强的广谱抗菌作用和良好的抗氧化活性。     

响应面试验优化苹果渣总三萜超声提取工艺

利用超声波提取技术结合响应面分析法对富士苹果渣中总三萜的提取工艺进行优化。选择苹果渣粉碎粒度、液固比、乙醇体积分数、超声时间和超声温度进行单因素试验,在此基础上采用Plackett-Burman因素筛选设计对影响超声波提取苹果渣总三萜的因素进行试验,筛选出影响显著的因素;然后根据Box-Behnken试验设计原理,选取三因素三水平,以苹果渣总三萜得率为响应值进行响应面分析,确定最优工艺参数。结果表明：Plackett-Burman设计筛选出粉碎粒度、液固比和乙醇体积分数为对苹果渣总三萜得率有显著影响的因素;通过响应面分析,确定苹果渣总三萜最优提取工艺为粉碎粒度100 目、液固比12∶1（mL/g）、提取溶剂为无水乙醇、超声时间20 min、超声温度40 ℃,在此条件下富士苹果渣总三萜的得率为（7.10±0.01）%。     

超声辅助提取日本荚蒾果实总三萜工艺优化及其抗氧化活性

为高效提取日本荚蒾果实中总三萜，采用超声辅助提取和响应面分析联用方法得到最优提取方案，并分析提取物的抗氧化活性。结果显示，乙醇浓度40%、料液比1∶12.5(g/m L)、超声温度50℃、超声时间74 min的工艺条件下总三萜得率为9.07%，与模型预测值9.16%有良好的拟合性。4个因素影响日本荚蒾中总三萜提取率的顺序为超声时间>料液比>乙醇浓度>超声温度。提取物抗氧化活性检测结果显示，自由基清除率随总三萜质量浓度增加有所升高并趋于稳定，总三萜质量浓度提高到2.5 mg/mL时，DPPH自由基清除率稳定在89%,ABTS+自由基清除率稳定在78%。     

超声提取柿果皮总三萜酸工艺优化

目的采用正交法优化柿果皮中总三萜酸的超声提取工艺。方法以"牛心柿"柿果皮为原料,利用紫外分光光度计法测定柿果皮中总三萜酸的含量,并从提取溶剂选择及其浓度、料液比、超声时间和温度等方面,通过单因素实验和正交试验确定超声提取柿果皮总三萜酸的最佳条件。结果最佳超声提取工艺为:在超声功率240 W的前提下,提取溶剂为75%(V/V)的乙醇、料液比1:15(m/V)、时间45 min、温度50℃。在此条件下,柿果皮总三萜得率最高可达39.33mg/g。结论优化后的方法简单、快速、准确、提取率高,适合提取柿果皮的总三萜酸。     

响应面试验优化牛樟芝总三萜提取工艺

对牛樟芝总三萜提取工艺参数进行优化研究。采用单因素和响应面法优化最佳工艺条件。结果表明,牛樟芝总三萜提取最佳工艺参数为乙醇浓度78%、提取时间81 min、料液比1∶20(g/mL),在此条件下,牛樟芝总三萜得率为5.26%。方差分析表明,影响牛樟芝总三萜得率由大到小的因素为乙醇浓度提取时间料液比。研究结果表明响应面法可用来优化牛樟芝总三萜的提取工艺,通过牛樟芝总三萜的提取可为进一步开发药食同源类产品提供借鉴作用。     

超声波辅助提取杜氏盐藻油脂工艺研究

对杜氏盐藻油脂的超声波提取工艺进行了研究,采用响应面分析法分析了液固比、超声时间和超声温度对盐藻油脂得率的影响,并建立了相应的预测模型。方差分析的结果表明,液固比、超声温度和超声时间对油脂得率都有显著影响(P<0.005),液固比的二次方项(P<0.005)和超声温度的二次方项(P<0.01)对油脂得率有显著影响,并且超声温度和时间存在交互作用(P<0.05),考虑到提取效率、成本和可行性,利用约束复合形法对结果进行优化,得到的最佳工艺参数为:在选用丙酮为提取溶剂的条件下,液固比29∶1 mL/g、超声时间47 min、超声温度48℃。在最佳工艺参数下,盐藻油脂得率为16.03%,与预测结果相符。     

响应面优化桦褐孔菌总三萜超声提取工艺

在单因素试验的基础上,根据中心组合试验设计原理,利用响应面分析法对桦褐孔菌总三萜超声提取过程中3个主要影响因素:超声时间、超声温度、料液比进行了优化。结果表明,超声提取温度、时间对三萜得率影响最为显著(p<0.001),最佳工艺条件为:采用异丙醇做提取溶剂,料液比为23mL/g,在60℃下超声提取22min。在此最佳条件下,总三萜得率为5.40%,试验结果与模型预测值相符。     

响应曲面法优化超声辅助提取虎杖中白藜芦醇的工艺研究

目的优化虎杖中白藜芦醇的提取工艺。方法以虎杖为原料,运用超声辅助提取技术对虎杖中的白藜芦醇进行提取,以乙醇溶液为溶剂,考察溶剂浓度、时间、温度、功率、料液比等因素对提取效果的影响,在单因素实验的基础上,通过响应曲面法优化提取工艺。结果最佳工艺参数为:乙醇浓度62.85%,超声时间37.92 min,温度60℃,料液比1:19.45(g/mL),超声功率240 W,此条件下白藜芦醇的提取得率为4.65%。结论本研究改进白藜芦醇的提取工艺,缩短提取时间,提高提取得率,可为白藜芦醇的提取和开发应用提供参考。     

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.