在新闻纸废纸浆中添加超微粒子助留助滤剂的研究

在新闻纸废纸浆分别添加超微粒子双元及三元助留助滤剂，测定浆的Zeta电位及PCD胶体电荷量，留着率及滤水时间，优化最佳的助剂添加量。实验证明双元助滤助滤剂N1、N2的添加量均为0．4kg／t，Zeta电位为-5．9mV，PCD为-244．4ueq／L，留着率为75．37％，滤水时间为17．9s，协同效果最好。三元助留助滤剂。N1、N2的添加量均为0．3kg／t，N3的添加量为1．3kg／t时，Zeta电位为-4．4mY，PCD为-244．0ueq／L，留着率为81．34％，滤水时间为11．1s，效果最佳。     

新型微粒子助留助滤体系在竹、木浆混合系统的应用

考察了CPAM／阴离子胶体硅微粒子助留助滤体系在竹、木浆混合系统的使用效果，并就该助留助滤体系对成纸强度性能的影响进行了探索。结果表明，对竹、木浆混合系统，CPAM和阴离子胶体硅的合适用量分别为0．4kg／t-0．6kg／t和0．2kg／t-0．4kg／t，在较大的CPAM用量（=0．6kg／t）和较大的阴离子胶体硅用量（=0．6kg／t）下，CPAM／阴离子胶体硅微粒子助留助滤体系助留效果变化不大。此外，在相同条件下，该体系能在快滤水和填料等细小物质高留着的前提下，保持较高的纸页强度性能。     

高档薄型包装纸造纸系统助留降耗技术研究

以聚胺类助剂为定着剂,阳离子聚丙烯酰胺为助留剂,有机硅胶为助滤剂,组成适合高档薄型包装纸生产系统的三元造纸助留助滤体系,有效留存细小纤维,降低网下白水浓度,浆耗从助留前的1．09t浆／t纸降低为1．03t浆／t纸。     

一元助留助滤剂生产低定量新闻纸方法的实践

采用阳离子聚胺盐与丙烯酰胺的共聚物的一元助留助滤系统生产低定量新闻纸,生产数据表明：一元助留助滤系统化学品用量少,并且仅需1个化学品添加点,生产流程简单;吨纸化学品添加成本为20．68元,比三元助留助滤系统化学品添加成本降低21％;成纸质量达到了国家标准GB1910-2006中45g／m^2低定量新闻纸优等品的要求。     

高填料纸张助留助滤体系的研究

在优化了针、阔叶木浆料与配比的前提下,考察了CPAM和PAE的湿部化学特性和增强作用,比较了CPAM／MMT、PAE／APAM、PAE／CPAM／MMT、PAE／CPAM／APAM对高填料纸的助留助滤效果的影响。结果表明：CPAM和PAE单独使用时,加入量最佳为绝干纸料的0．2％和1．25％;CPAM／MMT双元体系的助留助滤效果最好;PAE／CPAM／MMT的助留效果远好于PAE／CPAM／APAM,但其助滤效果仅略好于PAE／CPAM／APAM。     

微粒助留助滤体系对烟草薄片浆料助留助滤性能的影响

在造纸法烟草薄片的生产中,利用食品安全级的阳离子壳聚糖和瓜尔胶与膨润土和胶体二氧化硅组成二元微粒助留助滤体系,研究其对烟草浆料助留助滤性能的影响。研究结果表明：使用壳聚糖／膨润土或瓜尔胶／膨润土组成的二元微粒助留助滤体系能明显改善烟草浆料的留着率和滤水性能。壳聚糖（用量为0．1％）与膨润土（用量为0．4％）所组成的二元微粒体系与只添加0．1％的壳聚糖相比,烟草浆料单程留着率和填料留着率分别提高14％和12％,20s内滤水量提高200g。     

环保型功能助剂在脱墨浆中的应用研究

以淀粉衍生物为主料,通过引入离子型功能单体和高分子交联剂,合成了环境友好型的阳离子功能助剂。探讨了功能助剂对脱墨浆成纸的增强作用、助留助滤性能。当w（助剂）=0．3％（对绝干浆）时,成纸裂断长与空白样相比增加22．1％,脱墨浆留着率达到90．5％,滤水时间减少18．7％。新闻纸厂中试结果表明：吨纸助剂用量为10kg时,与未加助剂时相比成纸裂断长提高300m,灰分质量分数增加1．5％。     

福建南纸新闻纸清洁生产工艺研发项目通过鉴定

由福建南纸股份有限公司承担的福建省新闻纸清洁生产工艺研究开发项目近日通过专家鉴定。该公司经多年研究，优选了适合高速纸机的三元微粒助留助滤系统，研发了有自主知识产权的三元微粒助留助滤的添加方法。三元微粒助留助滤系统在1600m／min高速纸机上应用，有效地增加了纤维的留着率，提高了纸机的运行效率，降低了白水浓度。     

CMC在抄纸湿部系统的应用

研究了羧甲基纤维素(CMC)在湿部系统的应用,分析了其对打浆、助留助滤、成纸物理指标的影响。结果显示:浆料中添加一定量CMC后较容易打浆;CMC在湿部系统应用有助于提高细小纤维和填料的留着,但对滤水有不利影响,且当用量超过2kg/t浆时影响较严重;CMC能有效提高成纸物理强度,随着C M C用量的增加成纸物理强度逐渐升高,用量超过1.5kg/t浆后,变化趋缓。综合分析,CMC在抄纸湿部系统的用量为1.5kg/t浆时较合适。     

脱水助剂的类别及其特性

造纸时添加脱水助剂的主要作用是改善纸料的滤水性能，提高纸机产量，减少干燥蒸汽消耗。对某特定纸机或纸料，添加脱水助剂还可以改善纸机运行性能，减少压榨负荷，使用滤水较慢的纸料。作为脱水助剂的聚合物，往往起助留作用，能提高细小纤维和填料的留着率。1脱水助剂的类别     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

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.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

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.     

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.