双孢菇深层发酵培养基的响应面优化

研究了碳源、氮源、无机盐对双孢菇胞外多糖产量的影响.在单因素实验的基础上,采用响应面实验设计对双孢菇(Agaricus bisporus)深层发酵生产胞外多糖的培养基进行了优化,并建立了葡萄糖、KH2PO4、蛋白胨变化的二次回归方程,探讨了各因子对胞外多糖产量的影响.最终确定适宜的培养基条件为葡萄糖35.7g/L,KH2PO42.1g/L,蛋白胨3.1g/L;在此条件下可得到胞外多糖的最大产量,预测值为1.86g/L,对实验结果进行验证,得到胞外多糖的产量为1.87g/L.     

干酪乳杆菌LC2W合成胞外多糖培养基成分的优化

研究了不同培养基对干酪乳杆菌LC2W胞外多糖产量的影响，并研究了以脱脂乳为基础培养基，添加不同碳源、氮源和其他盐类对LC2W胞外多糖产量的影响。结果表明，不同培养基对LC2W胞外多糖产量影响较大，其中PTYG和脱脂乳培养基胞外多糖产量较高；以脱脂乳培养基为基础培养基，添加质量分数1．0％大豆蛋白胨、1．5％葡萄糖、0．1％的K2HPO4可以提高胞外多糖产量28.75％。     

响应面法优化枯草芽孢杆菌产胞外多糖培养基

从酒药中分离筛选出一株产胞外多糖枯草芽孢杆菌(Bacillussp.)。以胞外多糖的产量为指标,通过响应分析法对细菌胞外多糖产生的发酵培养基进行了初步研究。首先利用单因子实验对培养基中不同成分及添加量进行优化,然后在此基础上利用Box-Behnken中心组合实验设计对影响胞外多糖产量的因素进行优化分析,从而获得最适产胞外多糖的培养基组成。研究结果表明,枯草芽孢杆菌产胞外多糖最佳培养基组成为(g/L):蔗糖25.449、蛋白胨15.229、柠檬酸三钠2.971、牛肉膏3.0、硫酸镁1.0,在此条件下枯草芽孢杆菌胞外多糖的产量为3.554g/L。     

德式乳杆菌QS306产胞外多糖的特性研究

该文将德氏乳杆菌QS306分别在MRS培养基和脱脂乳培养基进行培养,然后进行醇沉,透析并用苯酚硫酸法测定胞外多糖的产量且进行抗氧化活性的研究。结果表明,脱脂乳培养基中胞外多糖的产量是MRS培养基中胞外多糖产量的5倍;脱脂乳培养基中所产胞外多糖对DPPH·和OH·的清除能力比MRS培养基中所产的胞外多糖的清除能力好,并且具有较强的还原力。因此在脱脂乳培养基中培养的德氏乳杆菌QS306所产的胞外多糖产量高且具有较好的抗氧化活性。     

双歧杆菌BB12胞外多糖发酵条件优化及抗氧化活性研究

为提高双歧杆菌BB12胞外多糖(exopolysaccharide,EPS)的产量,并探究其抗氧化活性,该文通过单因素试验分析初始p H值、培养温度和培养时间对胞外多糖产量的影响,在此基础上通过响应面法进一步优化发酵工艺参数,并对胞外多糖的还原能力、·OH和·O_2~-的清除作用进行了研究。结果表明,最优发酵条件修正后为:初始p H值8、培养温度37℃、培养时间101 h。在此条件下进行发酵验证,得到的胞外多糖产量为(131. 6±0. 82) mg/L。体外抗氧化性试验表明双歧杆菌胞外多糖具有还原能力,对·OH和·O_2~-的50%清除浓度(IC_(50))均低于抗坏血酸(Vc)。为双歧杆菌胞外多糖的大规模生产及抗氧化机制的研究提供了可靠的理论依据。     

分阶段控制温度提高胞外多糖产量

利用冬虫夏草头孢菌发酵生产胞外多糖,研究不同温度下对菌体生长和胞外多糖产量的影响。结果表明:26℃是菌体生长的最适温度,28℃是产物积累的最适温度。在此基础上,提出分阶段控制温度工艺。通过响应面法分析,得到优化方案为第一阶段温度26℃,变温时间17 h,第二阶段温度28.5℃,胞外多糖产量10.92 g/L,比28℃恒温培养提高了25.5%。     

影响乳酸菌胞外多糖产量的因素

乳酸菌胞外多糖是乳酸菌在生长代谢过程中分泌到细胞壁外、常渗于培养基中的一类天然生物高分子聚合物。乳酸菌胞外多糖不仅具有多种生物活性,而且还可作为食品增稠剂和稳定剂等,在改善发酵乳品质地和流变学特性等方面发挥重要作用。但是至今,乳酸菌胞外多糖的产量依旧较低,从而限制了其广泛应用,因此深入了解影响乳酸菌胞外多糖产量的因素具有深远的意义。文章综述了菌体自身遗传特性、培养基成分、培养条件及提取条件对胞外多糖产量的影响,并探讨提高其产量行之有效的措施,以期推动乳酸菌胞外多糖的研究和应用。     

不同碳源对阿魏菇菌丝生长量及多糖产量的影响

阿魏菇是一种极具发展前景的食药两用大型真菌,实验用液体摇床培养法与平板培养法培养阿魏菇,对其在不同碳源培养基中的胞外多糖产量及菌丝生长情况进行了研究。结果表明,蔗糖为阿魏菇生长利用的最佳碳源,液体培养基中菌球长势好,胞外多糖产量高,平板培养菌丝生长速度快。葡萄糖作碳源培养前期胞外多糖量增加快,但胞外多糖产量和菌丝量不如蔗糖作碳源时高。以麦芽糖作碳源液体培养菌球生长不完整。阿魏菇对乳糖利用情况最差,胞外多糖产量及菌丝量均为最低。     

真菌发酵胞外多糖的研究进展

真菌胞外多糖具有高黏性、抗氧化、抗病毒和抗肿瘤等多种生物学活性,在食品和医药工业等领域应用广泛。本文结合国内外最新研究成果,综述了近年来有关产胞外多糖的真菌、影响真菌胞外多糖产量的因素、产胞外多糖的菌株的选育策略以及真菌胞外多糖的功能研究,以期为真菌发酵胞外多糖的研究和应用提供参考。     

乳酸菌胞外多糖的生物合成及其遗传调控

作为食品级的乳酸菌分泌的胞外多糖,由于其具有很多优良的功能特性,成为了近年来的研究热点。胞外多糖产量偏低限制了其工业化应用,因此从基因水平上探索增加乳酸菌胞外多糖产量的途径是大有裨益的。文中详细阐述了胞外多糖的分类、结构,同型多糖和异性多糖生物合成过程及其差异,以及在合成过程中的遗传调控,并介绍了一些增加产量的有效调控手段,为深入的研究提供理论参考。     

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.