水蒸气蒸馏法提取大蒜油的工艺研究

文章研究了水蒸气法提取大蒜油的工艺,考察了单因素料液比、酶解温度、酶解时间、蒸馏加热温度、蒸馏时间的影响,通过正交实验,得出最佳工艺条件:蒜泥与水料液比1∶2,50℃条件下酶解3 h,再在温度为80～100℃条件下蒸馏2 h,出油率高达4.54‰。     

虎杖中白藜芦醇提取工艺研究

白藜芦醇是一种重要的活性天然产物,本研究以虎杖为原料,研究了白藜芦醇的溶剂法和酶解法提取工艺,考察了料液比、提取时间、提取温度、pH、酶加入量等对提取得率的影响．通过正交实验优化了溶剂法和酶解法的最佳工艺参数．实验结果表明：溶剂法优化工艺为：pH 5,料液比1:65,提取温度是60 ℃,提取时间2 h;酶解法优化工艺为：pH 6,料液比1:40,酶解温度是60 ℃,酶解时间2 h,二者得率分别是：0.496%和0.942%。酶解法的得率大约是溶剂法的2倍,可以作为虎杖中白藜芦醇提取的优选方法。     

响应面优化纤维素酶法提取茶花多糖工艺及其抗氧化活性研究

目的:优化纤维素酶提取茶花多糖的工艺,并评价其抗氧化活性。方法:以茶花多糖得率为响应值,在单因素实验基础上,以液料比、酶解温度、酶解时间、酶添加量为实验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件;采用自由基清除能力体系评价茶花多糖的抗氧化活性。结果:通过二次回归模型响应面分析,影响茶花多糖得率的因素按主次顺序排列为:酶解时间酶解温度液料比酶添加量;确定纤维素酶酶解茶花多糖最佳工艺条件为纤维素酶添加量5.0 mg/m L、液料比9∶1 m L/g、酶解温度48℃、酶解时间71 min,在此条件下茶花多糖得率为15.28%,模型方程理论预测值为15.91%,两者相对误差小于5%。茶花多糖具有较强的抗氧化活性,对DPPH和O-2·自由基的半数抑制浓度分别为0.974、1.342 mg/m L,但与维生素C比较,抗氧化活性较弱。结论:采用响应面法优化得到了茶花多糖的最佳提取工艺,该工艺方便可行,得到的多糖具有较强的抗氧化活性。     

响应面优化纤维素酶法提取桂花多糖工艺及其抗氧活性研究

目的:优化桂花多糖的提取工艺,并评价桂花多糖的抗氧化活性。方法:以桂花多糖得率为响应值,在单因素实验基础上,以液料比、酶解温度、酶解时间、酶添加量为实验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件;采用自由基清除能力体系评价桂花多糖的抗氧化活性。结果:通过二次回归模型响应面分析,影响桂花多糖得率的因素按主次顺序排列为:纤维素酶添加量酶解时间液料比酶解温度;确定纤维素酶解桂花多糖最佳工艺条件为纤维素酶添加量6.0mg/m L、液料比8∶1m L/g、酶解温度55℃、酶解时间80min,在此条件下桂花多糖得率为18.43%,模型方程理论预测值为19.05%,两者相对误差小于5%。桂花多糖具有较强的抗氧化活性,对DPPH和O2-·自由基的半数抑制浓度分别为0.846mg/m L、1.256mg/m L,但与维生素C比较,抗氧化活性较弱。结论:采用响应面法优化得到了桂花多糖的最佳提取工艺,该工艺方便可行,得到的多糖具有较强的抗氧化活性。     

莪术挥发油酶法提取工艺及抗氧化活性研究

试验旨在研究纤维素酶辅助水蒸气蒸馏法提取莪术挥发油的工艺,并探究其抗氧化活性。在单因素试验结果基础上,以酶添加量、酶解pH及酶解时间为自变量,挥发油得率为响应值,利用Box-Behnken响应面法进行工艺优化。以DPPH和羟自由基清除率为指标考察莪术挥发油的体外抗氧化活性。纤维素酶酶解提取莪术挥发油的最佳工艺为酶添加量1.6%、酶解pH 4.6、酶解时间2.1 h、酶解温度50℃、料液比1∶10 g/mL,此条件下挥发油得率为5.24%,显著高于水蒸气蒸馏法得率2.17%。莪术挥发油对DPPH和羟自由基具有较强的清除作用,半数抑制浓度分别为0.783 mg/mL和0.814 mg/mL。纤维素酶辅助提取法可显著提高莪术挥发油得率,工艺简便可行,获得的莪术挥发油具有抗氧化活性。     

鸡骨草多糖的酶法提取工艺优化及其抗氧化活性

目的:研究纤维素酶提取鸡骨草有效成分多糖的最佳条件,并探讨其体外抗氧化活性。方法:以鸡骨草多糖得率为响应值,在单因素实验基础上,以液料比、酶解时间、酶添加量、酶解温度为自变量,采用响应面法建立数学模型,筛选最佳提取工艺条件,并采用DPPH·和·OH清除能力体系评价鸡骨草多糖体外抗氧化活性。结果:最佳提取条件为:液料比13∶1 m L/g,纤维素酶酶解时间60 min,酶添加量12.8 mg/m L,酶解温度50℃,pH5.0,在此条件下鸡骨草多糖得率为8.15%,与理论值8.34%相对误差小于5%。酶添加量对多糖得率影响最大,液料比、酶解时间次之,酶解温度影响最小。鸡骨草多糖对DPPH·和·OH清除的半数抑制浓度IC_50分别为1.591、1.926 mg/m L,与维生素C比较,抗氧化活性较弱。结论:鸡骨草多糖纤维素酶酶法提取工艺方便可行,酶解得到的多糖具有较强的体外抗氧化活性。     

超临界流体CO2提取法与水蒸汽蒸馏法提取南五味子挥发油的成分比较

目的:比较超临界流体CO2提取法和水蒸汽蒸馏法提取南五味子挥发油的主要化学成分.方法:通过正交试验确定超临界流体CO2提取的最佳工艺条件,采用超临界流体CO2提取和水蒸汽蒸馏法提取五味子挥发油,并采用GC-MS方法分析成分.结果:超临界流体CO2提取的最佳工艺条件为提取温度40℃、提取压力15MPa、提取时间3h,在此条件下南五味子挥发油得率为8.2%,鉴定出16个成分.水蒸汽蒸馏法提取南五味子挥发油得率为1.4%,鉴定出24个成分.结论:超临界流体CO2提取南五味子挥发油的得率比水蒸汽蒸馏法高,挥发油的组分和含量均有一定的差异.     

纤维素酶法提取决明子粗多糖的工艺优化及其抗氧化活性

目的:优化纤维素酶法提取决明子粗多糖的工艺,并研究决明子粗多糖的体外抗氧化活性。方法:在单因素实验的基础上,以酶解时间、酶解温度、酶用量、液料比及酶解pH为自变量,多糖得率为响应值,利用BoxBehnken响应面法进行工艺优化。以对DPPH自由基和羟自由基清除率的大小为指标考察决明子粗多糖的体外抗氧化活性。结果:纤维素酶法提取决明子粗多糖最佳工艺为酶用量1.4%、酶解时间50 min、液料比24:1 mL/g、酶解pH5.4、酶解温度48℃,此条件下决明子多糖得率为11.67%,与回归模型的理论预测值11.91%误差小于5%。决明子粗多糖对DPPH自由基和羟自由基均具有较强的清除作用,半数抑制浓度分别为1.025 mg/mL和0.894 mg/mL。结论:纤维素酶法可显著提高决明子粗多糖得率,工艺简便可行,获得的决明子粗多糖具有体外抗氧化活性。     

响应面法优化大蒜油的提取工艺研究

以新鲜大蒜为原料，采用水蒸气蒸馏法提取大蒜油，研究萃取温度、萃取时间、蒸馏水体积对大蒜油得率的影响，在单因素试验的前提下，以大蒜油得率为响应值，进行Box-Behnken中心组合试验设计，采用响应面法（response surface methodology，RSM）评估萃取温度、萃取时间、蒸馏水体积对大蒜油得率的影响，以确定大蒜油提取的最佳工艺条件。结果表明，水蒸气蒸馏法提取大蒜油最佳工艺条件为萃取温度35℃、萃取时间5 h、蒸馏水体积480 mL，此条件下大蒜油得率高达0.482%。     

蓝莓多糖的优化提取及抗氧化性研究

研究了将纤维素酶法和超声波辅助法用于从提取花色苷后的蓝莓残渣中提取多糖的工艺,以达到优化工艺的目的;同时将粗多糖脱色脱蛋白后经二乙氨基乙基纤维素DE52柱层析纯化得到的精多糖SPⅠ进行抗氧化试验,检测其抗氧化性。通过正交试验设计,确定了最佳酶解提取工艺。结果为:酶法:酶解时间为100 min,酶解温度为40℃,酶添加量为0.6%,料水比为1 g∶60mL,条件最佳,蓝莓多糖的得率为2.319%。超声波辅助法:提取时间为40 min,提取温度为50℃,超声波功率为80 W,料水比为1 g∶60 mL,条件最佳蓝莓多糖的得率为2.335%。工艺比传统水提法简单,得率高;抗氧化试验显示SPⅠ具有较强的抗氧化性质。     

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.