纤维素酶脂肪酶处理旧新闻纸脱墨效果比较

纤维素酶和脂肪酶对ONP都有一定的脱墨作用,在相同工艺流程及各自的最佳脱墨条件下,脂肪酶处理ONP脱墨效果明显优于纤维素酶;脂肪酶比纤维素酶处理后脱墨浆白度高出1.82％ISO,残余油墨含量降低了3．7mm2／g,撕裂指数高1.1 mN·m2／g,断裂长高0.15 km,脱墨率高18％。     

纤维素酶处理旧彩色画报纸脱墨

采用纤维素酶处理旧彩色画报纸脱墨，就影响脱墨效果的脱墨浆浓、酶用量、酶作用时间、浮选剂用量，脱墨温度及pH进行了试验。初步确定在反应温度50℃，pH5．0时选用浆浓10％，酶用量50μ／g干纸浆，反应30rain，浮选剂用量0．20％，可以使脱墨浆白度达到69．3％IS0，残余油墨含量下降至11．17mm……2／g，脱墨率达到71．3％。     

高活性生物复合酶废纸脱墨的研究

以纤维素酶、木聚糖酶和蛋白酶等组成的复合酶对旧报纸进行脱墨，研究了脱墨中各种因素对脱墨效果的影响，得到脱墨的较佳工艺条件为：酶用量0．201U／g，碎浆浓度15％，脱墨时间35min，脱墨温度50℃，pH值5．0；并对漂白前后脱．圣浆的性能指标进行了比较。用此复合酶脱墨工艺，脱墨达到了较好的效果，有可工业化生产应用的良好前景。     

脂肪酶和纤维素酶/木聚糖酶混合用于ONP脱墨

将脂肪酶和纤维素酶/木聚糖酶以不同比例混合用于旧报纸(ONP)的脱墨实验.结果表明,当脂肪酶与纤维素酶/木聚糖酶混合酶(50/50)以40/60的比例混合时,能获得较佳的脱墨效果,浆料的裂断长、耐破指数和撕裂指数分别比纤维素酶/木聚糖酶(C/X)脱墨浆提高3.2%、7.4%、和7.1%,得率高于纤维素酶、木聚糖酶及二者的混合酶脱墨浆,滤水性能也得到了改善.混合酶中脂肪酶、纤维素酶和木聚糖酶用量分别比单一酶脱墨节省了60%、70%和70%.     

生物酶法脱墨在MOW中的研究进展

混合办公废纸（MOW）已成为重要的造纸纤维来源。利用生物前法脱墨对MOW脱箍是一种新的造纸技术。酶法脱墨在MOW中的使用主要包括纤维素酶、淀粉酶、脂肪酶，多组分复合使用协同作用更佳．本文主要就国内外生物酶法脱箍在MOW中的研究进展和脱墨机理作一报道。并对酶法脱墨的同题和前景作一浅析。     

脂肪酶用于混合办公废纸脱墨的研究

混合办公废纸（MOW）有较高的回收利用价值，但目前传统的碱性脱墨体系对其脱墨能力较弱，脱墨效率低下。故本文利用脂肪酶用于MOW的脱墨，讨论其最优脱墨工艺条件，分析其脱墨效率。研究发现脂肪酶Lipasefrom Candida rugosa的脱墨效率为86．0％，成纸白度为80．22％ISO、脂肪酶Lipase from porcine pancreas的脱墨效率为91．13％，成纸白度为83．08％ISO。     

脂肪酶用于废报纸脱墨的研究

研究了脂肪酶对废报纸的脱墨作用，优化了脂肪酶脱墨的工艺条件，并与两种化学脱墨剂的脱墨效果进行了比较。结果表明脂肪酶的脱墨效果优于化学脱墨剂，对纤维强度没有负面影响。H2O2漂白后，脂肪酶脱墨浆的返黄值低于化学脱墨浆。     

混合办公废纸纤维素酶脱墨的工艺研究

采用四种不同纤维素酶制剂进行混合办公废纸酶法脱墨实验，对脱墨浆性能和脱墨效果进行综合评价。从既能提高脱墨率，又尽可能保持物理强度方面考虑，在本实验条件下，同时存在内切酶、外切酶与木聚糖酶且FPA／CMCase值为0．0292的纤维素酶比较适合办公废纸酶法脱墨，其脱墨率最高，为82．3%；裂断长仅比对照样低0．8％，成纸强度好；最佳脱墨条件：加酶量：1．0IU／g(CMCase)，温度：50—55℃，pH值，5．0—5．5，时间：30—45min；浆浓5．0—5．5%。     

混合办公废纸酶法脱墨的研究

将几种纤维素酶和半纤维素酶应用于混合办公废纸的酶法脱墨中。研究了碎浆时问和碎浆浓度对脱墨效果的影响，并对几种酶对混合办公废纸脱墨浆性能的影响进行了比较。研究表明，与对照浆相比，纤维素酶和半纤维素酶的加入能显著降低脱墨浆的尘埃度。同时，在较低酶用量作用下，酶处理可以改善脱墨浆的抗张强度。几种酶相比，单组分的内切酶DeniMax 401具有最好的脱墨效果，当酶用量为0．2ECU／g时，脱墨浆的尘埃度比对照浆下降了60．6％，并且保持了良好的物理性能。     

混合办公废纸超声波酶法脱墨的研究

采用纤维素酶与超声波协同对混合办公废纸进行脱墨探索,实验结果表明,酶法脱墨的较佳工艺条件为纤维素酶处理温度50℃,纤维素酶用量为1．5IU／g,纤维素酶处理浆浓5％,纤维素酶处理时间60min,表面活性剂用量为0．05％,酶处理PH值为5．5,浮选时间15～20min,浮选浓度1％。超声波脱墨的较佳工艺条件为超声波频率...     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.