大头金蝇幼虫抗菌肽提取纯化及抑菌活性研究

目的:从大头金蝇幼虫中分离纯化天然抗菌肽,并检测抗菌肽的抑菌活性。方法:提取大头金蝇幼虫抗菌肽,粗提物经凝胶过滤色谱、阳离子交换树脂、反相色谱纯化,纯化产物检测其抑菌活性并利用GFC-HPLC测定其分子量。结果:最终纯化出一个活性组分,该组分对铜绿假单胞菌的最小抑菌浓度为20.40μg/m L,对金黄色葡萄球菌的最小抑菌浓度为2.04 mg/m L,对大肠杆菌的最小抑菌浓度为0.17 mg/m L;该活性组分分子量大小为2570 u。结论:该抗菌肽组分对铜绿假单胞菌有较强抑菌活性,有较好的开发利用价值。     

不同菌种发酵羊胎盘残留物制备活性肽研究比较

采用枯草芽孢杆菌、米曲霉以及黑曲霉发酵羊胎盘残留物,利用膜过滤、超滤等方法进一步分离纯化并对各组分以抗氧化和免疫细胞增殖能力的研究,探究微生物发酵制备胎盘肽的可行性。结果表明,枯草芽孢杆菌、米曲霉以及黑曲霉发酵三种微生物发酵产物的多肽含量分别是389.6μg/m L,403.8μg/m L和434.7μg/m L;三种微生物的多肽原液在稀释5倍后具有较高的自由基清除率,黑曲霉和枯草芽孢杆菌的DPPH·及·OH清除率达到60%和80%左右,二者的多肽原液在浓度为100μg/m L时对免疫细胞的刺激指数达24.89%和22.81%;对三种菌的多肽原液进一步的分离纯化后得到6个分子量组分的含量分布,其中产物80%的均在3×104 Da分子量以下,分子量大小对产物的生物活性有一定的影响并对各组分进行抗氧化活性与免疫细胞增殖活性的研究。     

硫磺菌凝集素的提取工艺研究

硫磺菌凝集素是一种从硫磺菌子实体中提取的、能凝集红细胞的蛋白质。本文以硫磺菌为原料,采用磷酸缓冲溶液浸提,对氯化钠浓度、液料比、提取温度、提取时间、浸提p H五个因素进行单因素实验,并设计四因素三水平的正交实验,以研究硫磺菌凝集素的最佳提取工艺。研究结果表明:氯化钠浓度为0 mol/L,液料比为30∶1 m L/g,提取温度为15℃,提取时间为10 h,浸提p H为7.5的条件下,硫磺菌凝集素的凝集活性最高,达到0.5870,蛋白得率为0.576%。     

响应面法优化鲟鱼精蛋白的提取工艺

以鲟鱼-甲骨板的精巢组织为原料,从中提取鱼精蛋白粗品,建立硫酸提取分离鱼精蛋白的最优工艺。以蛋白得率为指标,通过单因素实验研究硫酸浓度、液料比、提取温度、提取时间和提取次数的影响大小,初步确定鱼精蛋白的最佳分离条件。进一步利用响应面软件Box-Behnken设计模型确定鲟鱼精蛋白的最佳提取工艺条件,结果表明:硫酸浓度0.83 mol/L,液料比6.2∶1 m L/g,提取时间0.5 h,提取温度35℃,提取次数4次。经验证,最优工艺条件下鱼精蛋白的得率平均达到11.28%,且纯度高达86.13%,分子量约为10 ku,有良好的抑菌活性,金黄色葡萄球菌抑菌圈直径达15.75 mm。     

HILIC-MS/MS法检测动物源运动营养品中9种抗病毒药物残留

目的:加强动物源性运动营养品中抗病毒药物残留的监控.方法:建立一种亲水交互作用色谱—串联质谱测定动物源运动营养品中9种抗病毒药物组分的方法.样品前处理采用1%乙酸—乙腈提取,经PRi ME HLB小柱净化后检测.采用乙腈—10 mmol/L乙酸铵溶液(含0.1%甲酸)流动相体系,在梯度洗脱模式下,经Sielc Obelisc R柱分离,实现9种目标物组分的分离.结果:9种抗病毒药物组分在0.1～20.0ng/m L质量浓度范围内线性良好,检出限为0.1～0.5μg/kg,定量限为0.3～1.5μg/kg,加标回收率达82.3%～95.7%,相对标准偏差为3.2%～5.9%(n=5).结论:试验方法可以满足动物源运动营养品中9种抗病毒药物残留的检测需求.     

燕麦蛋白组分分离提取及其SDS-PAGE电泳分析

通过单因素实验对燕麦蛋白组分的分离提取工艺进行了优化,并通过SDS-PAGE电泳对燕麦蛋白组分进行亚基分析。结果表明:燕麦清蛋白提取的最佳温度为40℃,球蛋白提取最佳盐浓度为7%,醇溶蛋白提取的最佳乙醇浓度为75%,谷蛋白提取的最佳碱浓度为0.05 mol/L,蛋白质提取率为83.1%。SDS-PAGE实验结果显示:燕麦清蛋白在10~100 kD范围内均有分布,燕麦球蛋白由2个亚基组成,分子量分别在97.4~100 kD和43~66.2 kD范围内,燕麦醇溶蛋白亚基大部分集中在18.39~40.72kD之间,燕麦谷蛋白部分亚基分布在20.67~26.66kD与43.29~50.80 kD之间。     

低谷蛋白稻米组分蛋白提取工艺优化

为确定低谷蛋白稻米蛋白质组分的最优提取条件,以低谷蛋白水稻D105为材料,用连续提取法,在优化提取液浓度的基础上,采用响应面法 (RSM) 优化各组分蛋白的提取条件。结果表明,球蛋白提取最适提取氯化钠溶液浓度为0.6 mol/L、醇溶蛋白最适乙醇浓度为80%、谷蛋白的最适提取浓度为0.04 mol/L;基于单因素试验,选择料液比、提取时间、提取温度、提取次数为自变量,以各组分蛋白提取量为响应值,利用Box-Behnken (BB)中心组合设计4因素三水平试验,确定清蛋白最佳提取条件为：料液比1:22、提取温度31.6 ℃、提取时间43 min、提取3次;球蛋白最佳提取条件为：料液比1:20、提取温度33.1 ℃、提取时间22 min、提取3次;醇溶蛋白最佳提取条件为：料液比1:21、提取温度34.6 ℃、提取时间40 min、提取2次;谷蛋白最佳提取条件为：料液比1:16、提取温度34.7 ℃、提取时间22 min、提取3次。在此条件下稻米各组分蛋白的提取量分别为：清蛋白4.26 mg/g、球蛋白9.76 mg/g、醇溶蛋白2.27 mg/g、谷蛋白23.60 mg/g,与预测值的相对误差分别为 0.0187、0.0563、0.0308、0.014,表明响应面法优化所得提取工艺条件较好,具有应用价值。     

枸杞多糖的提取分级及其氧自由基清除能力分析

研究枸杞多糖的超声波辅助提取工艺条件,采用超滤方法对枸杞多糖进行分级,并对其氧自由基清除能力进行分析。试验结果表明,超声波提取枸杞多糖的最佳工艺条件为:料液比1:20 g/mL、提取温度65℃、提取时间20 min,在此条件下,提取1次时枸杞多糖的提取率可达27.19%。枸杞多糖中,相对分子质量小于5 ku的占60.73%,相对分子量在5 ku～30 ku的占23.04%;氧自由基清除能力测定结果表明,相对分子量为30 ku～50 ku的枸杞多糖组分的Trolox当量为119.45μmol/L,高于未经超滤和其他分子量分布的枸杞多糖组分,提示该组分具有较强的抗氧化能力。试验结果为枸杞多糖的深度开发利用提供了一定的科学依据。     

大鲵黏液糖蛋白的提取工艺优化及纯化表征

本文以丽水人工养殖大鲵的黏液为原料,优化大鲵黏液粗糖蛋白提取工艺并进行纯化表征。基于单因素实验,以料液比、温度、提取液浓度以及提取时间为考察因素,粗糖蛋白得率为指标,采用响应面法优化提取工艺,得到最佳提取条件为:料液比1:30.5 g/mL、提取温度51 ℃、提取液浓度0.32 mol/L、提取时间5.2 h,大鲵黏液粗糖蛋白得率最高为5.22%±0.71%。纯化得到大鲵黏液糖蛋白（MGP）,经表征分析,测定其达到电泳纯,分子量约为29 kDa;MGP中必需氨基酸及药用氨基酸含量分别为37.21 g/100 g和33.39 g/100 g;MGP具有典型的糖蛋白结构的紫外全波长吸收图像;含有O型糖肽键,吡喃糖环结构和β-糖苷键,β-折叠结构占蛋白质二级结构的87%,为后续深入探究大鲵黏液糖蛋白生物活性提供一定基础。     

响应面分析法优化非洲山毛豆种子凝集素提取工艺的研究

在单因素试验基础上采用响应面分析法优化非洲山毛豆种子凝集素的提取工艺。研究表明:TBS缓冲液为非洲山毛豆种子凝集素的最佳提取溶液;非洲山毛豆种子凝集素提取的优化工艺条件为料液比1:40(g/mL),pH8.0,Nacl浓度0.125mol/L,提取时间16h。     

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.