圆果黄麻的制浆性能试验

对圆果黄麻的纤维形态、化学成分及制浆性能进行了研究。结果表明,圆果黄麻韧皮部纤维平均长度为2.17mm,木质芯部平均长度为0.64mm;圆果黄麻全秆的纤维素和木素含量均低于针叶材和阔叶材;热水抽出物、1%NaOH抽出物、苯-醇抽出物含量均高于针叶材和阔叶材;圆果黄麻全秆适于采用机械法、烧碱-蒽醌法、硫酸盐法、碱性亚硫酸钠法制浆。     

芒秆的化学成分特征以及制浆方法的研究

主要研究了芒秆的化学成分对浆得率和漂白的影响。实验用芒秆材料采自于浙江农林大学实验地。实验对芒秆的水分、灰分、苯-醇抽出物、克拉森木素及综纤维素的含量进行了定量分析,明确了各成分对浆得率和ECF、TCF漂白的影响。本实验用硫酸盐法对芒秆进行蒸煮,通过改变其蒸煮温度、时间和活性碱添加率等,测得了浆得率及卡伯值。毛竹、洋麻韧皮和桉木进行了同样的实验进行比较。分析了影响浆得率、TCF漂白和ECF漂白的各种因素,并且验证芒秆原料的制浆可行性。     

竹柳与两种速生阔叶木的材性和制浆性能比较

对竹柳和毛白杨、巨尾桉三种速生阔叶材的原料化学组成、纤维特性和硫酸盐法制浆性能进行了研究。研究结果表明:竹柳的冷水抽出物、热水抽出物和1%NaOH抽出物含量均比毛白杨和巨尾桉高,灰分和苯醇抽出物含量比毛白杨低,但比巨尾桉高;竹柳的综纤维素含量低于毛白杨和巨尾桉,但聚戊糖含量相对较高,可以推断出竹柳的纤维素含量相对较低;竹柳的木素含量也相对较低。竹柳原料和其硫酸盐浆的纤维平均长度均比毛白杨和巨尾桉小,但纤维宽度和粗度介于毛白杨和巨尾桉之间。经硫酸盐法蒸煮后,竹柳纤维粗度下降到72.9μg/m。同时,竹柳的粗浆得率为50.80%,与毛白杨基本持平;竹柳未漂硫酸盐浆的物理性能略好于毛白杨和巨尾桉。     

烟秆的化学成分、纤维形态与生物结构

为促进烟秆在造纸法再造烟叶中的应用,采用制浆造纸原料分析方法和烟草化学分析方法,分析了四川产烟秆的化学成分、纤维形态和生物结构。结果表明:1烟秆的灰分、冷水抽出物、热水抽出物、1%NaOH抽出物、苯醇抽出物和果胶含量均远远低于烟梗和烟叶碎片,高于常规造纸纤维原料;烟秆的综纤维素、硝酸-乙醇纤维素、木素和聚戊糖含量均远远高于烟梗和烟叶碎片,与阔叶材和禾本科原料相当。2除总氮和蛋白质含量与烟梗和烟叶碎片相当外,烟秆的总糖、还原糖、总植物碱含量均较低。3烟秆的重均纤维长度为0.69 mm、宽度为17.74μm,长宽比为38.97,壁腔比为0.68,柔性系数为69.9,纤维细胞含量为71.5%。4烟秆木质部的细胞类型包括导管、木射线和木纤维,具有与阔叶材十分相似的生物结构。     

离子液体[Mmim]DMP对不同木质纤维的溶解性能

研究了咪唑类离子液体1,3-二甲基咪唑磷酸二甲酯盐[Mmim]DMP对于制浆造纸纤维原料桉木、芒秆和蔗渣的全组分溶解过程。结果表明:[Mmim]DMP在一定条件下对三种原料的溶解率分别为6.34%、9.24%和19.36%。对原料、未溶残渣和溶解析出物进行红外光谱和扫描电镜观察发现,三种原料在溶解过程中纤维素、半纤维素和木质素三种成分都被部分溶解,但其中桉木木素更易于溶解在离子液体。溶解后桉木残渣的木质素相对含量下降明显,综纤维素相对含量上升,表明[Mmim]DMP对桉木有较好的木质素溶出效果。     

十二种桉树化学成分分析及其硫酸盐法制浆适宜性评价

桉树是一种重要的速生阔叶木,在全球广泛种植,主要用于制浆造纸企业。对十二种6年生桉树的化学成分、纤维形态,制浆造纸性能进行分析,评价它们的硫酸盐法制浆适宜性。十二种桉树在抽出物(6.1%~18.9%),木质素(21.6%~30.8%)和综纤维素(55.4%~70.1%)含量方面存在显著差异,化学成分的巨大差异导致了桉树不同的制浆得率(38.9%~49.8%)和脱木素程度(卡伯值11.6~24.2)。将这些结果与纤维形态、手抄纸性能综合考虑,蓝桉、卵叶桉、巨尾桉、柳桉、葡萄桉的硫酸盐法制浆适宜性最好。     

改良杂交尾细桉材性特征随树龄变化及APMP制浆性能分析

本文主要研究了人工改良杂交尾细桉LH1和天然杂交尾细桉U6的基本密度、化学组分、纤维形态随树龄的变化趋势及APMP制浆性能分析。结果表明,两种桉木的基本密度、综纤维素含量、纤维长度、纤维宽度及长宽比随树龄呈增加趋势,灰分含量、1%NaOH抽出物含量随树龄呈下降趋势。两种桉木纤维长度在0.6-0.8mm之间,长宽比在34.4~42.4之间,小于45,属于短纤维原料。改良后LH1的基本密度、综纤维素含量、长宽比高于天然杂交尾细桉U6,利于制浆造纸。经相同条件制浆漂白后,250mL游离度的纸浆,LH1的抗张指数提高42.3%,耐破指数提高87.5%,撕裂指数提高49.5%。     

12种桉树化学成分分析及其硫酸盐法制浆适宜性评价

桉树是一种重要的速生阔叶木,在全球广泛种植,主要用于制浆造纸工业。对12种6年生桉树的化学成分、纤维形态,制浆造纸性能进行分析,评价它们的硫酸盐法制浆适宜性。12种桉树在抽出物(6.1%~18.9%)、木素(21.6%~30.8%)和综纤维素(55.4%~70.1%)含量方面存在显著差异,化学成分方面的巨大差异导致了桉树不同的制浆得率(38.9%~49.8%)和脱木素程度(卡伯值11.6~24.2)。将这些结果与纤维形态、手抄纸性能综合考虑,蓝桉、卵叶桉、巨尾桉、柳桉、葡萄桉的硫酸盐法制浆适宜性最好。     

粗皮桉AS-AQ法制浆特性的研究

桉木是造纸工业生产的重要原料,具有优良的制浆造纸性能,本研究首次采用粗皮桉为原料,研究其制浆性能,为造纸工业生产提供理论数据。实验的主要结果如下:家系123粗皮桉AS-AQ法蒸煮最佳工艺条件为总碱量(以Na2O计)25%,亚硫酸化度(以Na2O计)0.5,蒽醌0.08%,NP-10用量0.3%,保温时间160min,最高蒸煮温度170℃,液比1∶4.5,家系200的最佳工艺条件为总碱量(以Na2O计)23%,亚硫酸化度(以Na2O计)0.50,蒽醌0.08%,NP-10用量0.3%,保温时间150min,最高蒸煮温度170℃,液比1∶4.5。     

国内造纸期刊题录 (摘录)

原料与备料D N30杂交白杨———高强度阔叶木浆的纤维资源范景阳编译国际造纸2004,5:60废纸使用常见问题及对策刘军钛等纸和造纸2004,5:22不同品质桉木的制浆造纸性能分析苏燕妮等造纸科学与技术2004,5:14油棕榈空心果球纤维原料的性能分析魏丽芬等西南造纸2004,5:51制浆生产山东首套进口杨木A P M P制浆系统运行经验刘世海等中国造纸2004,10:65P-R C A P M P工艺与生产调试吴平武中华纸业2004,10:27桦木化学机械浆和杨木漂白硫酸盐浆之间的协同作用张正健等编译国际造纸2004,5:25制浆设备白水回收多圆盘过滤机的选型及计算龚香玲等中…     

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.