柠檬醛对指状青霉菌丝体膜脂过氧化的影响

探讨柠檬醛对指状青霉菌丝体膜脂过氧化的影响。研究发现,经最小抑菌浓度（minimal inhibitoryconcentration,MIC,2.0 μL/mL）和最小杀菌浓度（minimal fungicidal concentration,MFC,4.0 μL/mL）柠檬醛处理后,指状青霉菌丝体发生扭曲变形且表面出现明显褶皱,表明细胞完整性遭到破坏。不同质量浓度柠檬醛处理指状青霉后,其胞外电导率及K＋泄漏量均显著增加,而总脂质含量降低,说明柠檬醛处理能增加指状青霉细胞膜通透性,导致细胞膜结构遭受破坏。进一步研究发现,MIC、MFC柠檬醛处理促使指状青霉总丙二醛含量、过氧化氢含量和脂氧合酶、过氧化物酶活性升高。本研究结果表明：柠檬醛处理可诱导指状青霉菌丝体发生严重的膜脂过氧化损伤,损伤细胞膜结构,从而抑制指状青霉菌丝体生长。     

柠檬醛对指状青霉糖酵解的影响

本研究测定了不同浓度柠檬醛对指状青霉呼吸代谢及糖酵解途径相关指标的影响。结果表明,柠檬醛能明显抑制指状青霉的呼吸代谢,1.0μL/m L浓度下柠檬醛与糖酵解途径、三羧酸循环途径以及磷酸戊糖途径典型抑制剂(碘乙酸,丙二酸,磷酸钠)的叠加率分别为15.00%、12.60%和30.70%,且此结果显示糖酵解途径受到了柠檬醛的影响。经最小抑菌浓度(minimal inhibitory concentration,MIC,2.0μL/m L)和最小杀菌浓度(minimal fungicidal concentration,MFC,4.0μL/m L)柠檬醛处理后,指状青霉糖酵解途径重要的中间产物葡萄糖和丙酮酸的含量显著增加,己糖激酶(Hexokinase,HK)的活性下降,6-磷酸果糖激酶(Phosphofructokinase,PFK)和丙酮酸激酶(Pyruvate kinase,PK)的活性增加。本研究表明柠檬醛能够抑制指状青霉的呼吸代谢,改变指状青霉糖酵解途径关键酶的活性和重要中间产物的含量。     

α-松油醇对意大利青霉的抑制作用

测定α-松油醇对意大利青霉菌丝体形态及菌丝体生长的影响,并对其抑菌机制进行初步探讨。结果表明:α-松油醇能明显抑制意大利青霉菌丝体生长,最小抑菌浓度(minimal inhibitory concentration,MIC)和最小杀菌浓度(minimal fungicidal concentration,MFC)分别为2.00μL/mL和8.00μL/mL;经MIC和MFCα-松油醇处理后,意大利青霉菌丝体胞外pH值、胞外电导率及260 nm条件下吸光度显著增加,总脂质含量有显著下降。提示α-松油醇能改变细胞膜的通透性、破坏细胞膜结构的完整性,导致胞内成分泄露,从而抑制意大利青霉菌丝体生长。     

不同发育期椪柑精油对意大利青霉和指状青霉的抑制作用

对不同发育期(7、8、9和10月)的椪柑(Citrus reticulata Blanco)果皮精油进行GC-MS分析,共鉴定出柠檬烯(47.28％ ～58.40％)、γ-松油烯(8.27％ ～13.23％)、β-芳樟醇(3.48％ ～7.86％)、β-月桂烯(6.24％ ～7.50％)、α-蒎烯(5.07％～6.05％)、β-蒎烯(2.30％～3.45％)和辛醛(2.04％ ～2.48％)等50种萜烯类化合物.椪柑果皮精油及其所含的6种潜在抑菌组分(柠檬醛、辛醛、壬醛、癸醛、β-芳樟醇和α-松油醇)的体外抑菌实验结果表明:不同发育期椪柑果皮精油对意大利青霉(Penicillium italicum)的抑制作用要强于指状青霉(P.digitatum);潜在抑菌组分中柠檬醛和辛醛对意大利青霉的抑菌效果最好,壬醛和辛醛对指状青霉的抑菌效果最好.柠檬醛和辛醛对意大利青霉的最小抑菌浓度(MIC)、壬醛和辛醛对指状青霉的MIC均为0.50μL/mL;β-芳樟醇和α-松油醇对意大利青霉和指状青霉的MIC均为2.00μL/mL.     

柠檬皮中的柠檬苦素对青霉的抑菌活性和机理研究

通过测定最低抑菌浓度(minimum inhibitory concentration,MIC)和最小杀菌浓度(minimum fungicidal concentration,MFC)、孢子萌发抑制率、菌丝生长抑制率确定柠檬皮中柠檬苦素对青霉的抑菌活性;结合总糖含量和蛋白质含量、碱性磷酸酶(alkaline phosphatase, AKP)活力等的变化,以及扫描电镜观察对抑菌机理进行研究。结果表明:柠檬皮中柠檬苦素对青霉有很强的抑菌活性,对青霉的MIC和MFC分别为625和2 500μg/mL,对青霉菌丝生长和孢子萌发抑制的EC_(50)值分别为85.618和246.755μg/mL。柠檬苦素能在短时间内对青霉的细胞壁和细胞膜造成破坏,使胞内物质大量渗出;且柠檬苦素浓度越高,胞内物质渗出越多。扫描电镜观察也发现经柠檬苦素处理的青霉外附着渗出物;产孢数量变少,孢子变形;小梗破损、凹裂;菌丝变细,变形。     

α-松油醇对指状青霉抑霉唑抗性菌株Pdw03的抑制作用

本研究探讨了α-松油醇对指状青霉抑霉唑抗性菌株Pdw03的抑制作用及其抑菌机理。体外实验结果表明α-松油醇抑制Pdw03生长的最小抑菌浓度（minimal inhibitory concentration,MIC）和最小杀菌浓度（minimal fungicidal concentration,MFC）均为4.00 μL/mL;体内实验研究发现MFC和5 MFC α-松油醇可明显降低接种Pdw03椪柑果实的绿霉病发病率和发病直径;碘化丙啶（propidium iodide,PI）染色实验发现,经1/2 MIC α-松油醇处理后,Pdw03的细胞膜完整性降低,麦角固醇含量显著降低（P＜0.05）,麦角固醇合成相关基因ERG9表达量显著下调（P＜0.05）。综上,α-松油醇通过抑制ERG9基因的表达影响菌株Pdw03的生长,可作为采后柑橘病害防治的有效替代品。     

盐酸小檗碱抑制指状青霉的作用机制

本实验主要对盐酸小檗碱（berberine hydrochloride,BH）抑制指状青霉（Penicillium digitatum）生长的活性以及可能的作用机制进行探讨。结果表明,BH抑制指状青霉生长的最低抑菌质量浓度（minimum inhibitory concentration,MIC）和最低杀菌质量浓度（minimum fungicidal concentration,MFC）分别为0.16 g/L和0.32 g/L;用MIC的BH处理15 h孢子萌发率仅为（4.40±1.05）%,显著低于对照组（（92.48±3.35）%,P＜0.05）;此外,10 MFC的BH可显著延缓采后柑橘果实绿霉病的发病进程,接种5 d的果实病斑直径为（1.13±0.02）cm,显著低于对照组（（5.62±0.09）cm,P＜0.05）;扫描电子显微镜观察结果表明,BH处理使指状青霉菌丝体褶皱变形。进一步实验发现,BH处理30 min时,指状青霉菌丝体细胞壁完整性和细胞膜通透性受损,胞外碱性磷酸酶活性和可溶性蛋白质量浓度均有所上升,但胞内ATP含量和能荷水平均降低;处理60 min时,活性氧大量积累导致膜脂过氧化,线粒体功能受损,能量代谢进一步失衡。结论：BH能有效抑制指状青霉的孢子萌发和菌丝生长,并延缓柑橘果实绿霉病的发病进程,其抑菌机理可能与影响菌丝体细胞通透性和能量代谢有关。     

江香薷活性成分香芹酚对指状青霉的抑菌作用

以指状青霉菌(Penicillium digitatum)为供试菌,研究江香薷活性成分香芹酚的抑菌活性及其抑菌机理。本文采用二倍稀释法测定其最小抑菌浓度(MIC)和最小杀菌浓度(MFC),以此评价香芹酚对指状青霉菌的抑菌效果;并通过研究香芹酚对指状青霉的菌丝形态变化、孢子萌发率、细胞膜渗透性和菌体内可溶性糖含量,阐述香芹酚对指状青霉菌的抑菌机理。结果表明:香芹酚对指状青霉菌的MIC、MFC分别为0.125 mg/mL和0.25 mg/mL;经不同浓度香芹酚处理后的指状青霉,菌丝形态发生明显改变,孢子萌发率显著降低,细胞膜渗透性增强,菌体内可溶性糖含量降低。说明香芹酚能有效抑制指状青霉菌的孢子萌发,破坏细胞膜结构完整性,内含物外渗,降低营养物质含量,影响病原菌正常生长发育,从而发挥抑菌效果。     

柑橘绿霉病中草药高效抑菌剂的筛选及抑菌机理研究

利用牛津杯法筛选出对柑橘绿霉病菌(指状青霉)有最佳抑制作用的中草药提取物,并通过测定培养液电导率变化等对其抑菌机理作进一步研究。结果表明:桂枝、桂皮、香薷等乙醇提取物对指状青霉均有较好的抑制效果,抑制圈均在20 mm以上,其中以桂枝的抑菌活性最佳,对指状青霉的抑制圈大小达31.56±0.66 mm,最小抑菌浓度(MIC)和最小杀菌浓度(MFC)分别为6.25mg/mL、12.5 mg/mL,且其抑菌效果显著优于化学杀菌剂百可得。同时桂枝提取物对指状青霉菌的孢子萌发及菌丝生长发育也有较强的抑制作用,在提取液处理浓度为50 mg/mL时,孢子萌发抑制率高达99.007%,菌丝体细胞膜通透性增强,菌丝体可溶性蛋白及总糖含量分别只有1187.18μg/g及0.307%,菌丝形态呈现畸形甚至断裂,因而桂枝提取物对柑橘绿霉病菌有明显的抑菌活性,其抑菌作用主要是通过破坏细胞膜结构,扰乱菌丝物质代谢活动来实现的。     

柠檬皮中柠檬苦素对黑曲霉的抑菌特性和机理

本研究以柠檬皮中柠檬苦素为原料,对其抑制黑曲霉的抑菌活性、抑菌活性的稳定性和抑菌机理进行了研究。结果表明:柠檬皮中柠檬苦素对黑曲霉的最小抑菌浓度(MIC)和最小杀菌浓度(MFC)分别为625μg/mL、5000μg/mL;对孢子萌发和菌丝生长抑制的半最大效应浓度(EC50)分别为311.03μg/mL和291.63μg/mL。柠檬苦素对黑曲霉的抑菌活性在紫外光照下受到抑制;在pH值为6～7时受到抑制;金属离子Fe3+、Fe2+可增强其抑菌活性。在柠檬皮中柠檬苦素作用下,黑曲霉的胞外碱性磷酸酶(AKP)活力、可溶性蛋白和菌丝体总糖含量发生很大变化;扫描电子显微镜观察发现黑曲霉孢子发生了变形、破裂、溶出物附着的现象。因此,柠檬苦素破坏了黑曲霉细胞壁和细胞膜的完整性,造成大量内容物渗出,影响了细胞正常代谢,进而抑制了菌体细胞的生长繁殖。     

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.