响应面法优化鹿角菜中岩藻多糖的超声波辅助提取工艺

采用超声波辅助提取鹿角菜中岩藻多糖,以岩藻多糖提取率为指标,研究超声时间、液料比、水浴温度和水浴时间4个参数对提取效果的影响,并采用Box-Benhnken设计(BBD)来优化提取工艺,确定提取条件为超声时间60 min,液料比51 m L∶g,水浴温度91℃,水浴时间5 h。在此条件下,岩藻多糖提取率达到5.961%,与理想预测值(5.993%)相比,相对误差小于5%;与传统水提法相比,提取总时间缩短了2.4 h,多糖提取率提高了0.79%。通过自由基体系评定发现,岩藻多糖具有较强的抗氧化活性,且还原力随着质量浓度的增加不断提高,对羟自由基(·OH)、超氧阴离子自由基(O~-_2·)和1,1-二苯基-2-三硝基苯肼(DPPH)自由基的半数抑制浓度IC_(50)分别为0.346、0.893和0.128 mg/m L;但与Vc相比,对羟自由基、超氧阴离子自由基清除作用较弱,但对DPPH的半数抑制浓度IC50小于Vc。     

黑加仑果渣提取物抗氧化活性研究

以黑加仑果汁加工后的果渣为原料,通过微波-超声辅助提取法提取果渣中多糖及水、醇萃取物;采用体外抗氧化体系研究果渣提取物超氧自由基、羟基自由基、DPPH自由基的清除能力,采用红外对多糖进行表征。结果表明:多糖为α-吡喃糖;多糖、醇提取物浓度在0.8 mg/mL时DPPH自由基、羟基自由基清除率达到90%以上,水提取物达到80%以上;其多糖超氧自由基清除率达到60%以上;水、醇提取物超氧自由基在50%以上。所以,提取物具有显著抗氧化活性,具有好的开发前景。     

裸藻多糖碱提工艺优化及其体外抗氧化活性研究

以NaOH浓度、提取时间、提取温度对裸藻多糖(Paramylon)得率影响的单因素实验为基础,进行Box-behnken中心组合实验来优化碱提裸藻多糖的提取工艺,并在体外测定裸藻多糖对1,1-二苯基-2-苦基肼自由基(1,1-Diphenyl-2-picrylhydrazyl Free Radical,DPPH)、羟自由基(·OH)的清除能力以及总还原力的大小。结果表明,碱提裸藻多糖的最佳提取条件为NaOH浓度0.6 mol/L、提取时间3h、提取温度50℃,在此条件下多糖的实际提取率为42.35%,与预测值相近。裸藻多糖清除DPPH自由基、·OH的半抑制质量浓度(IC_(50))分别为0.3、0.1 mg/mL,具有较好的体外抗氧化能力。     

繁枝蜈蚣藻多糖的抗氧化活性研究

目的:研究繁枝蜈蚣藻多糖的体外抗氧化能力.方法:采用从繁枝蜈蚣藻中提取的已纯化的水溶性多糖(WGZ-b),测定了繁枝蜈蚣藻多糖的还原力、抗氧化能力.结果:高浓度繁枝蜈蚣藻多糖的还原力高于BHT和PG.多糖对清除几种自由基都有较好的作用,其清除DPPH·、O2-·的IC50值分别为116、84.0μg/ml.繁枝蜈蚣藻多糖对几种自由基的抑制能力由大到小依次为:O2-·＞DPPH·＞·OH.因此繁枝蜈蚣藻多糖有很强的抗氧化能力,值得深入研究其生理功能和开发功能产品.结论:繁枝蜈蚣藻多糖具有较明显的体外抗氧化能力.     

铁皮石斛多糖提取及抗氧化活性研究

从铁皮石斛中提取多糖。以铁皮石斛多糖提取得率为评价指标,在单因素试验的基础上通过正交试验优化提取条件,得到最佳提取条件:提取时间2h,料液比1∶80,提取温度80℃,提取次数3次。此条件下铁皮石斛多糖提取得率为19.01%±0.49%。通过测定铁皮石斛多糖对1,1-二苯基-2-苦肼基(DPPH)、超氧阴离子自由基(O~(2-))和羟基自由基(-OH)的清除能力及铁皮石斛多糖对三价铁的还原能力,对铁皮石斛多糖进行抗氧化活性研究。结果表明,铁皮石斛多糖对三种自由基均有较高的清除能力,且清除能力随多糖浓度的增加而增大,在多糖浓度为3mg/mL时,自由基清除率分别达到38.83%、56.25%、56.58%。同时铁皮石斛多糖具有较高的还原能力。铁皮石斛多糖具有较强的抗氧化活性。     

3种方法提取的雨声红球藻多糖的理化性质及抗氧化活性比较

以雨声红球藻(Haematococcus pluvialis)为原料,研究超声辅助酸提取、超声辅助碱提取、超声辅助水提取3种不同提取工艺对雨声红球藻多糖提取效率和产品理化特性的影响,在此基础上对3种多糖抗氧化活性进行比较分析。结果表明,3种提取方法所得多糖提取率大小依次为:超声辅助碱提法(9.52%)超声辅助酸提法(1.50%)超声辅助水提法(1.29%)。傅里叶红外变换光谱分析结果表明,3种多糖的组成单糖中均包含吡喃糖,成苷的半缩醛羟基主要为α构型,其中以酸提多糖的吸收峰最强。扫描电子显微镜证实了超声辅助碱提法对雨声红球藻细胞壁的破坏程度最大,胞内多糖溶出最多。通过对还原力、1,1-二苯基-2-苦基肼自由基清除能力和·OH清除能力等抗氧化活性的测定,表明3种多糖均具有一定的抗氧化能力,其中以碱提多糖的综合抗氧化能力最优。由此可见,超声辅助碱提法是一种提取藻多糖较好的方法。     

蛤蒌叶提取物抗氧化活性研究

目的探究不同提取条件下,蛤蒌叶提取物的抗氧化活性。方法在不同提取条件下,采用匀浆-超声波法对蛤蒌叶进行粗提取,并对不同提取物的DPPH(1,1-diphenyl-2-picrylhydrazyl)自由基清除能力进行分析。结果蛤蒌叶乙醇提取物对DPPH有较好的清除作用,当乙醇浓度为100%、提取温度为55℃、提取时间为8 h时,蛤蒌叶提取物对DPPH自由基的清除效果较佳。在较佳的提取条件下蛤蒌叶提取物的黄酮含量为62.29 mg/g、多酚含量为61.83 mg/g、多糖含量为391.43 mg/g、蛋白质含量为62.28 mg/g。结论蛤蒌叶乙醇提取物的抗氧化活性优于水提取物,当乙醇浓度达到100%时抗氧化活性最强,且乙醇提取物的黄酮、多酚和蛋白质含量要明显高于水提物,两者的多糖含量则相当。     

花果山云雾茶中多酚和多糖的超声同步提取工艺

研究花果山云雾茶中茶多酚和茶多糖的超声辅助同步提取工艺并评价提取物的抗氧化活性。在单因素试验的基础上,响应面分析法优化的提取工艺为:超声功率500 W,提取温度80℃,提取时间37 min,液料比62∶1(mL/g)。在优化的条件下,茶多酚和茶多糖的得率分别为(137.08±3.37)mg/g和(57.71±1.94)mg/g。固态提取物的得率为(2.51±0.27)%,其中茶多酚和茶多糖的含量分别为(548.31±13.48)mg/g和(227.28±6.44)mg/g。通过测定提取物的还原力、抗氧化力和对DPPH自由基、羟自由基及超氧阴离子自由基的清除能力评价其抗氧化活性,结果显示提取物具有较强的还原力和总抗氧化力及清除DPPH自由基、羟自由基和超氧阴离子自由基的活性。     

亚麻荠籽多糖提取工艺的响应面优化 及其体外抗氧化活性

以亚麻荠籽饼为原料,以多糖得率为指标,在单因素试验基础上采用响应面试验对恒温搅拌提取亚麻荠籽多糖工艺进行优化,并探讨亚麻荠籽粗多糖提取物的体外抗氧化活性。结果表明,恒温搅拌提取亚麻荠籽多糖的最佳工艺条件为提取温度90 ℃、料液比1∶ 18、提取时间85 min、搅拌速度200 r/min,在此条件下提取2次,亚麻荠籽多糖得率为1.71%。亚麻荠籽粗多糖提取物对DPPH自由基与羟自由基均呈现出一定的清除能力,对羟自由基的清除能力优于DPPH自由基。研究结果为亚麻荠籽多糖的提取以及应用提供了理论依据。     

超高压提取青钱柳多糖条件优化及抗氧化活性

试验以青钱柳叶为原料,研究青钱柳多糖的超高压提取工艺,对提取的青钱柳粗多糖进行抗氧化活性试验。采用单因素及正交试验对青钱柳多糖的超高压提取工艺进行优化,结果显示,青钱柳多糖最佳提取条件为:料液比1︰25(g/mL)、提取温度30℃、提取压力500 MPa。在此条件下,青钱柳多糖得率最高,为3.70%。将青钱柳粗多糖进行清除DPPH自由基、清除羟基自由基试验,以抗坏血酸(VC)为对照,测定青钱柳叶粗多糖的体外抗氧化能力。结果表明,青钱柳叶粗多糖清除DPPH自由基效果较好且较对照组浓度低,最高清除率为93.0%,而清除羟基自由基效果低于对照。     

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.