杨木边角材及整材的特性比较

木材加工业在苏北地区的徐、淮、盐、连、宿等五市被作为支柱或重要产业之一,得到国家林业局和省政府的重点支持,在杨树规划区内的800余家木材加工有90％以上集中在苏北一带。因此,在此地区有十分丰富的杨木边角材资源,而且价格便宜。作为我公司造纸的加工制造原料,杨木边角材的使用不仅产生较为明显的经济效益,而且具有一定的社会效益。     

抑菌性桑枝低聚糖微胶囊的制备及结构表征

为了降低桑枝低聚糖的吸湿性,提高稳定性,拓展在产品开发中的应用,本实验以麦芽糊精、乳清蛋白为壁材,桑枝低聚糖为芯材,利用喷雾干燥制备稳定性良好、具有抑制变异链球菌活性的微胶囊。探究壁材种类及与芯材的质量比对微胶囊抑菌率的影响,并对微胶囊的吸湿性、分子结构、微观形态、热稳定性、贮藏稳定性等进行综合评价。结果表明:当复合壁材为麦芽糊精与乳清蛋白且质量比为2:1,壁材与芯材质量比为2:1时,制备的微胶囊具有较高的抑菌率（61.31%±3.34%）与较低的吸湿性（12.31%±1.47%）,粒径为6.58±1.76 μm。扫描电镜显示微胶囊颗粒形态完整,表面结构较为光滑;FITR表明微胶囊是麦芽糊精与乳清蛋白通过静电相互作用形成的,桑枝低聚糖较好地被包埋在微胶囊内部;X衍射分析证明桑枝低聚糖在微胶囊中结晶结构发生改变;微胶囊的玻璃化转变温度为96.10 ℃,高于一般贮藏温度。桑枝低聚糖制备成微胶囊后,在温度40.0、60.0 ℃,湿度RH 75.0%、RH 92.5%下稳定性提高。本研究可为桑枝低聚糖作为功能性配料提供一定的理论基础。     

速生材杨木P-RC APMP浆和桉木漂白化学浆间的协同效应

两种不同游离度(CSF)(480 mL和250 mL CSF)的速生材杨木P-RC APMP浆分别与桉木漂白硫酸盐浆(BKP)(CSF425 mL)混合,通过研究混合浆在物理性能和光学性能方面的变化,探讨了杨木P-RC APMP浆和桉木BKP浆之间的协同效应。研究结果表明,低游离度的杨木P-RCAPMP浆与桉木BKP浆混合后,能够在抗张强度、抗张能量吸收、湿抗张强度和撕裂度等方面产生协同效应;混合浆的松厚度和不透明度随杨木P-RC APMP浆配比量的增加而增加;但是混合浆的白度会受到较低白度的杨木P-RC APMP浆的影响。     

杨木边角料蒸煮工艺的研究

我公司所处地区是全国板材加工基地．有大量的杨木加工余料，品种以意大利63、69和72杨木为主。为了进一步拓宽造纸原料来源，我公司在年初进行了多次杨木边角料蒸煮实验，取得了不错的效果，现将实验情况叙述如下。     

混合枝桠材生产打字纸

混合枝桠材生产打字纸赵竟刘浩田（甘肃省镇原县造纸厂７４４５００）关键词混合枝桠材阔叶木制浆打字纸为解决麦草原料严重不足问题，我们采用混合阔叶木枝桠材（桦木、松木、杨木等），经剥皮削片生产打字纸。现将生产工艺情况简介如下：１原料备料阔叶木枝桠材经人工剥...     

木聚糖酶对混合杨木APMP浆滤水性能的影响

采用木聚糖酶处理混合杨木APMP浆,研究木聚糖酶对浆料滤水性能的影响,同时考察木聚糖酶对纸浆强度的影响。实验结果表明,木聚糖酶能有效改善混合杨木APMP浆的滤水性能,同时纸浆的强度性能略有提高。木聚糖酶改善混合杨木APMP浆滤水性能的最佳实验条件为:酶用量1.5U/g绝干浆、浆浓0.5%、pH值7.0、温度45℃、时间30min,在此条件下,与未经木聚糖酶处理的浆料相比,打浆度下降了4.5°SR,动态滤水时间明显缩短。     

阔叶木与非木材纤维原料混合制浆的研究

对阔叶木(杂交杨木)与非木材纤维原料(芒草、柳枝稷、玉米秸秆)的混合硫酸盐法制浆和ECF(无元素氯)漂白(漂序为OD(EP)D)进行了探讨。结果表明,在杨木木片中加入一定比例的上述非木材纤维原料(10%～30%)时,纸浆抗张强度有所提高,提高幅度在20%～25%之间。通过对纸浆碳水化合物组分进行分析发现,纸浆强度的提高与其聚木糖含量有关,即将少量聚木糖含量较高的非木材纤维原料与阔叶木一起混合蒸煮,能够获得品质优良的纸浆。     

桑枝-桉木板皮混合制浆漂白特性的研究

探究了不同桑枝替代率下桑枝-桉木板皮混合硫酸盐法制浆和ODEp漂白的特性。结果表明,桑枝的化学组分与桉木板皮存在较大差异,桑枝综纤维素含量低、木素含量高、纤维长度较长;在相同制浆漂白工艺下,桑枝较桉木难漂白,其所占比例越高,纸浆的卡伯值越高、白度越低,但桑枝替代率不超过30%时,纸浆具有较好的可漂性,氧脱木素效率在40%以上,漂白浆的白度在78%以上;另外,桑枝的加入可以提高混合浆的黏度和撕裂度,但对漂白浆的抗张强度和耐破度不利。     

混合枝丫材制造打字纸成功

原料不足问题,采用混合阔叶木枝丫材(包含桦木、杨木等),经剥皮削片,成功制造出定量28g/m~2的打字纸。简况如下: 1.木材备料:阔叶木枝丫材,人工剥去树皮,削成规格15～20毫米长、3～5毫米厚的木片,木片含水分20％左右,大小片均一。 2.蒸煮:采用NaOH-AQ法制浆,用     

两种预处理方法对杨木压缩变形的固定作用及性能影响

为了提高人工林杨木的尺寸稳定性和力学性能,采用乙酸酐酯化和MUF树脂浸渍两种预处理方法与热压缩相结合,制备出杨木酯化-压缩材和MUF浸渍-压缩材,木材处理前后的各项物理力学性能测试结果表明:酯化-热压缩和MUF浸渍-热压缩均可显著降低杨木的吸湿性和吸水性,提高杨木的密度及力学性能;酯化-热压缩后,杨木的压缩回弹固定效果更优,变形恢复率为1.7%;MUF浸渍-热压缩对杨木力学性能的改善效果更好,可使杨木密度由素材的0.39g/cm3提高到0.76g/cm3,表面硬度、弹性模量和抗弯强度分别比素材提高192%、196%和142%。     

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.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.