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1.
对木聚糖酶预处理麦草碱法化学机械制浆进行了研究。结果表明,在适宜的条件下,木聚糖酶预处理可以降低磨浆能耗,提高麦草碱法化机浆的抗张强度和撕裂强度,增加纸浆的白度。  相似文献   

2.
研究了青霉产木聚糖酶预处理对麦草碱法化学制浆和漂白性能的影响.在酶法化学制浆前采用机械预处理和蒸汽预处理原料可以一定程度地改善酶处理的效果,而且木聚糖酶处理对麦草制浆性能具有改善作用.在麦草生物化学浆漂白前利用青霉产木聚糖酶预处理纸浆,可以提高漂白浆的白度和撕裂强度.  相似文献   

3.
麦草生物化机浆木聚糖酶预处理H2O2漂白研究   总被引:8,自引:2,他引:6  
在麦草生物化机浆H2O2漂白时,采用单纯H2O2漂白难以获得较高白度的纸浆,但通过对浆料进行木聚糖酶预处理和在漂白过程中加入醋酸酐进行活化,可以改善H2O2漂白效率,提高漂白浆白度.麦草生物化机浆木聚糖酶预处理和醋酸酐活化处理的适宜条件分别为:木聚糖酶用量12IU/g绝干浆、120min和在H2O2漂白150min时加入5%醋酸酐处理10 min.采用木聚糖酶预处理、醋酸酐活化和H2O2漂白相结合的XP5aP5a漂白程序,可获得白度为74.6%ISO的漂白麦草生物化机浆.实验对酶预处理和漂白过程中纸浆化学成分的变化也进行了研究.  相似文献   

4.
在麦草化学浆H2O2漂白和CEH漂白时,采用自行选育的菌株ZCF-57生产的中性木聚糖酶进行预处理,研究了酶处理对漂白浆白度和漂白废水污染负荷的影响.结果表明,该木聚糖酶预处理可以有效地提高漂白浆白度,降低废水污染负荷.与对照浆相比,在达到相近白度时,预处理后H2O2用量可从5%减少到3%,P段废水BOD5、CODcr分别减少13.2%和17.0%;酶预处理可使CEH漂白产生的总CODcr和AOX分别降低50%和20%以上.  相似文献   

5.
麦草浆木聚糖酶预处理HD漂白研究   总被引:1,自引:0,他引:1  
研究了木聚糖酶预处理HD漂白麦草浆的效果。结果表明:Au—PE89木聚糖酶预处理麦草浆的最佳条件为:酶用量50g/t,温度50℃,时间90~120min,pH值7.0。在HD漂白工艺中增加木聚糖酶预处理段,可使纸浆白度提高2.6%ISO,漂白废液CODcr含量减少约50%。  相似文献   

6.
麦草碱法化学机械浆纤维特性研究   总被引:8,自引:0,他引:8  
用纸浆纤维筛分仪、FQA-纤维特性分析仪和扫描电子显微镜对不同预处理条件的麦草碱法化学机械浆的纤维特性进行了研究.结果表明,麦草碱法化学机械浆含有较多的P102/R203和P203组分,是其具有较高机械强度的原因,而木聚糖酶预处理可以进一步增加这部分纤维的含量,更有利于纤维的解离和提高纤维的柔软度,改善纸浆的物理性能.  相似文献   

7.
木聚糖酶预处理提高麦草化机浆可漂性及白度的研究   总被引:3,自引:0,他引:3  
探讨了麦草化机浆经木聚糖酶预处理后可漂性和白度的改善效果。  相似文献   

8.
木聚糖酶用于麦草浆ECF漂白的研究   总被引:3,自引:0,他引:3  
采用木聚糖酶对麦草烧碱蒽醌浆进行预处理,以期提高和改进浆料的ECF漂白性能,优化并制定出木聚精酶AU-PE89的预处理条件.实验结果表明,木聚糖酶AU-PE89的最佳处理条件为:pH值6,温度50℃,酶用量6 IU/g绝干浆.此条件下DP漂白浆的白度可达82.5%,提高1.0个百分点;DEP漂白浆的白度可达83.2%,提高2.1个百分点;DED漂白浆的白度可达81.6%,提高1.3个百分点,这表明用木聚檐酶进行生物漂白,能有效降低漂白时化学品用量.  相似文献   

9.
麦草NaOH-AQ浆ECF漂自   总被引:4,自引:0,他引:4  
对NaOHAQ麦草浆的DP高白度漂白进行了研究。结果表明,DP漂白浆白度可达81.6%ISO,强度性能良好。在DP漂白中的P段之前进行不同处理,可以改善漂白浆的性能。不同木聚糖酶处理都能够提高DP漂白麦草浆的白度,其适宜处理流程为DXP和DPX。  相似文献   

10.
姚光裕 《黑龙江造纸》2013,41(1):43-45,49
报导了用两种菌Ceriporiopsis subvermispora(C.S.)和Phlebia suberialis(P.S.)分别预处理麦草对碱-蒽醌(AQ)蒸煮得到麦草浆、纸性质的影响。结果表明:菌预处理麦草能提高脱木素和碳水化合物的降解作用,P.S.比C.S.预处理更能提高纸浆的白度、降低卡伯值和黏度。菌预处理浆在所有磨浆度情况下可提高纸页的松密度、白度和撕裂指数,而降低抗张和破裂指数,C.S.比P.S.预处理浆对提高纸页松密度和降低抗张、破裂指数更加明显。还研究了阳离子聚乙烯醇(CPVA)用作干强添加剂改性纤维能够弥补菌预处理对纸页强度的损失。C.S.比P.S.预处理的碱-AQ麦草浆更易吸附CPVA,从而提高纸页强度。应用CPVA对菌预处理未磨浆工磨浆的纤维,在相同抗张强度情况下,都能达到降低纸页定量的目的。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
16.
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.  相似文献   

17.
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.  相似文献   

18.
19.
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.  相似文献   

20.
Capillary electrophoresis (CE) and polarized light microscopy (PLM) were utilized in the detection of the adulteration of locust bean gum with guar gum. For CE analyses, standards of locust bean and guar gums were extracted with 30% CH3CN, removing the residual proteins from the gum matrix. A 8.75 mM NaH2PO4-20.6 mM Na2B4O7 buffer, pH 9, was used to separate these proteins and to identify marker proteins that were present in the guar gum. These markers did not co-migrate with components in the extracts of mechanically processed locust bean gum, and are used as indicators of adulteration. Using PLM with toluidine blue and iodine staining techniques, unadulterated locust bean gum samples were distinguished from mixed samples through the differential staining of components in locust bean versus guar and tara gums. These experiments in the use of CE and PLM provide orthogonal and complementary methods for the verification of 'true' positives and the elimination of 'false' positives.  相似文献   

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