辐射松预水解对后续蒸煮及氧脱木素过程木素脱除效果的影响

本文研究了辐射松木片预水解对蒸煮和后续氧脱木素过程的影响。结果表明,预水解温度为168℃,预水解时间在60~90 min时,半纤维素脱除率大于50%,而纤维素的损失率小于10%,且纤维素聚合度不降低;同时也能促进蒸煮过程及后续氧脱木素过程木素的脱除,蒸煮后纸浆卡伯值降低至16.3,氧脱木素后纸浆卡伯值降低至2.8。当预水解时间超过120 min,预水解则会对后续的蒸煮起阻碍作用,造成蒸煮困难,表现在纸浆卡伯值急剧上升,甚至出现生煮现象。预水解时间控制在180 min之内,预水解可以提高氧脱木素过程中木素的脱除率,预水解时间超过180 min,预水解对氧脱木素的影响则不明显。预水解对蒸煮过程的影响大于对氧脱木素过程的影响,尤其是过度预水解对蒸煮有阻碍作用,但是对后续氧脱木素的影响则不显著。     

溶解浆粕制备过程中降低聚戊糖含量的方法

在溶解浆粕的制备过程中,能否大量去除纸浆中的半纤维素从而提高其α-纤维素的比例是关键。研究了由木材原料通过蒸煮制备溶解浆粕过程以及由竹浆直接制备溶解浆过程中降低其半纤维素含量的方法。在由木片为原料通过蒸煮制备溶解浆的实验方案中,主要研究了预水解硫酸盐法中预水解工艺对纸浆中半纤维素含量的影响,认为预水解保温2h能较为有效地降低蒸煮所得纸浆的半纤维素含量;在由竹浆原料直接制备溶解浆的实验方案中,重点研究了酸处理工艺以及碱处理工艺对去除竹浆中的半纤维素以及降解纤维素聚合度方面的影响,并得出酸处理与碱处理相结合的方法能够最大限度地去除半纤维素同时保护纤维素聚合度。     

楠竹预水解硫酸盐法制浆工艺

以楠竹为原料生产竹浆粕,对水预水解和硫酸盐法蒸煮的工艺条件进行优化。结果表明:水预水解阶段最优工艺条件为P因子1000;硫酸盐蒸煮阶段最优工艺条件为H因子1000、用碱量17%(Na2O计)、硫化度20%。按此工艺条件所得的浆粕α-纤维素含量94.55%,黏度1096mL·g-1,细浆得率33.59%,卡伯值10.76,聚戊糖含量4.81%。     

芦苇预水解硫酸盐法人纤浆粕的制备及其预水解动力学研究

对芦苇预水解硫酸盐法试制人纤浆粕的预水解硫酸盐蒸煮最佳工艺条件及其动力学进行了研究。结果表明,芦苇的预水解反应为一级反应。水解过程中,只要控制P-因子相同,即可获得同样品质的半料浆。芦苇在175℃下、保温90min即可溶出约75%的戊聚糖和50%的木素。芦苇预水解的最佳条件为:最高温度175℃,保温时间90min,液比1∶6。芦苇预水解后硫酸盐蒸煮的最佳工艺条件为:用碱量10%(对绝干原料,以Na2O计),硫化度15%,最高温度160℃,保温时间30min,液比1∶4。经CEHA四段漂白后,所制得的人纤浆粕各项指标符合标准要求。     

桉木硫酸盐法蒸煮前预提取聚木糖的研究

研究了桉木硫酸盐法制浆前的半纤维素提取工艺。对桉木片进行预水解处理,通过改变温度和时间对半纤维素提取工艺进行优化。水解液中提取的聚木糖为12~38 g/L,相当于木片质量的9%-15%。对预水解后木片进行硫酸盐法蒸煮,结果表明,与未经预水解相比,预水解后木片更容易脱木素,成浆更易漂白,预水解中聚戊糖去除得越多,所得浆料的强度性能越低。     

竹浆纤维--浆粕的制备研究

研究用预水解硫酸盐蒸煮法制备再生竹纤维——浆粕。分析了预水解硫酸盐蒸煮的原理及工艺条件,简要介绍了多段漂白工艺,并测试了成品的质量指标。     

慈竹模拟置换蒸煮工艺研究

研究了慈竹模拟置换蒸煮过程中预浸渍段、温充段、热充段NaOH浓度及硫化度对置换蒸煮的影响。结果表明,在慈竹模拟置换蒸煮过程中,在一定范围内NaOH浓度升高时,有利于药液向慈竹内部的渗透,利于蒸煮;温充段对脱木素的贡献大于预浸渍阶段;热充段NaOH浓度对深度脱木素影响最显著。硫化度从23%提高到44%时,利于深度脱木素,浆料卡伯值下降显著,同时得率也随之下降。当预浸渍段、温充段、热充段的NaOH浓度分别为10、15～20、30 g/L,硫化度为23%～30%时,浆料卡伯值为10.7～17.8,得率为43.1%～45.1%。置换蒸煮与普通蒸煮相比,当成浆得率相当时,置换蒸煮成浆卡伯值较低;当卡伯值相当时,置换蒸煮成浆得率较高。     

再生竹纤维浆粕的制备研究

研究了预水解硫酸盐蒸煮法制备再生竹纤维浆粕的方法。分析了预水解硫酸盐蒸煮的原理，简要介绍了多段漂白工艺并测试了成品的的质量指标。     

醋化级芦苇溶解浆的制备及其性能

为探索使用可再生的芦苇资源制备醋化级溶解浆的可行性,以湖南洞庭湖区的南荻为原料,采用水预水解-硫酸盐法蒸煮-D₀E_pD₁(ClO₂漂白脱木素段-H₂O₂漂白段-ClO₂漂白增加白度段)3段漂白工艺制备了南荻浆粕,并对其甲种纤维素含量、白度、聚合度、多戊糖含量、灰分含量和铁含量,以及表观形貌、化学结构和晶体结构等进行测试与分析。结果表明：蒸煮后南荻的粗浆得率为46.31%,3段漂白工艺使南荻浆粕的主要性能指标得到明显改善,其甲种纤维素含量提高了1.24%达到97.70%,白度提高1倍达到91.42%,特性黏度降低38.01%,使南荻浆粕的平均聚合度达到1 413;制浆过程中高温、NaOH、Na₂S、ClO₂和H₂O₂的共同作用使南荻中的木质素、半纤维素和灰分得到有效去除。本文工艺制备的南荻浆粕的性能达到了醋化级溶解浆的基本要求,为下一步制备醋酯纤维素...     

热水预水解对杨木半纤维素提取及后续硫酸盐法制浆的影响

基于制浆造纸过程中的生物质精炼理念,利用热水预水解预先提取杨木木片中的半纤维素,然后对水解后的木片进行硫酸盐法蒸煮,探讨预水解因子（P因子）对半纤维素提取和后续硫酸盐法制浆的影响。研究结果表明,热水预水解对半纤维素的提取效果显著,且P因子可较好地控制预水解反应过程;预水解处理能提高后续硫酸盐法蒸煮脱木素的效果,降低蒸煮用碱量,但会增大后续浆料打浆难度,同时降低成纸的某些物理性能。综合考虑后续水解液的生物质利用和水解木片的硫酸盐法制浆,当P因子为608~1060时,水解液中的聚戊糖提取率为33.18%~35.31%,相应的预水解KP制浆得率为39.47%~37.12%;与未经热水预水解处理的对照样相比,热水预水解处理后浆料性能和黑液性能均较好。     

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.