臭氧对糖蜜酒精废液脱色效果的研究

通过对臭氧流量、废液pH值、反应温度、氧化时间 4个因素的实验摸索 ,得出采用臭氧氧化法处理酒精废液单因素影响的基本规律。以最佳条件组合 :流量 0 10m3 /h ,pH9 0 ,时间 90min做优化实验 ,脱色率为 5 6 92 %。     

臭氧对糖蜜酒精废液脱色机理及工艺优化

利用臭氧氧化法处理糖蜜酒精废液,碱性条件下其反应机理属于自由基型反应。通过正交实验确定影响因素的主次为:氧化时间→臭氧流量→反应温度→废液pH值;最佳工艺条件组合为:时间90min、流量0.10m3/h、温度60℃、pH9.0,脱色率为56.92%。     

内电解-催化氧化法处理糖蜜酒精废液的研究

采用内电解-催化氧化法处理糖蜜酒精废液具有较高的COD去除效果.研究了内电解-催化氧化法处理糖蜜酒精废液的效果受反应时间、废液浓度、pH值、反应温度等单因素的影响并进行了正交试验.实验结果表明,反应10h,废液稀释7.5倍,pH=5.50,反应温度60℃,用Cu-AC催化剂,内电解-催化氧化法处理糖蜜酒精废液,其COD...     

内电解-催化氧化法处理糖蜜酒精废液的研究

采用内电解-催化氧化法处理糖蜜酒精废液具有较高的COD去除效果。研究了内电解-催化氧化法处理糖蜜酒精废液的效果受反应时间、废液浓度、pH值、反应温度等单因素的影响并进行了正交试验。实验结果表明,反应10h,废液稀释7.5倍,pH=5.50,反应温度60℃,用Cu-AC催化剂,内电解-催化氧化法处理糖蜜酒精废液,其COD去除率可达80.0%。     

内电解—催化氧化法处理糖蜜酒精废液的研究

采用内电解—催化氧化法处理糖蜜酒精废液具有较高的COD去除效果。研究了内电解—催化氧化法处理糖蜜酒精废液的效果受反应时间、废液浓度、pH值、反应温度等单因素的影响并进行了正交试验。实验结果表明,反应10h,废液稀释7.5倍,pH=5.50,反应温度60℃,用Cu—AC催化剂,内电解—催化氧化法处理糖蜜酒精废液,其COD去除率可达80.0%。     

腐植酸在糖蜜酒精废液处理中的应用研究

针对糖蜜酒精废液的综合治理问题 ,利用腐植酸作吸附剂 ,提出了腐植酸处理糖蜜酒精废液的新思路 ,考察了pH、温度、腐植酸用量、磁力搅拌时间、腐植酸粒度、静置沉降时间、助凝剂用量等因素对腐植酸吸附效果的影响。结果表明 ,腐植酸粒度 80目、用量 2 0 %、废液pH7、室温、磁力搅拌 5分钟、静置沉降 4小时、外加助凝剂P30 0 0 0 7% ,腐植酸的吸附效果最佳 ,CODcr去除率达 80 0 %     

汉麻麻皮脱胶工艺与果胶提取

为解决常规汉麻脱胶后废液排放污染环境的问题,提出汉麻麻皮的超声波预处理-草酸铵-生物复合酶联合脱胶工艺。探讨超声波预处理时的功率、时间,草酸铵处理的浓度、温度、时间等因素对汉麻脱胶效果的影响。超声波预处理的最佳条件为:超声波工作频率40 kHz、功率120 W、温度50℃、时间35 min。草酸铵处理的最佳条件为:浴比1∶30、质量浓度4 g/L、温度100℃、时间50 min。汉麻麻皮脱胶后,将果胶从脱胶液中回收,分析得到果胶提取的最佳条件为:调节脱胶液pH至4.5,浓缩至脱胶液体积的15%。使用与浓缩液相同体积、体积分数为95%的无水乙醇作为沉淀剂,沉淀2 h。红外测试表明,获得的提取物为果胶。     

臭氧法处理造纸荧光增白剂生产废水的研究

采用臭氧氧化法对造纸荧光增白剂生产废水进行实验研究,对氧气流量、氧化时间和pH值等影响因素进行了优化。研究结果表明,当氧气浓度为60L/h,氧化反应时间为50min,pH为6,CODCr去除率达到63.5%,浓度由850mg/L降到310mg/L,水的色度由800倍降到100倍。臭氧处理方法可以很好的去除水中残留的荧光增白剂。     

PAC和PAM对魔芋精粉湿法生产溶剂的回收效果研究

利用正交试验设计，研究用混凝剂PAC和助凝剂PAM对魔芋湿法生产废液进行混凝处理，以回收溶剂——酒精溶液。考察了混凝剂的投入量、助凝剂的投入量、溶液的pH值、混凝时间、混凝温度对回收效果的影响。研究结果表明，混凝剂PAC的投入量为300mg／L，助凝剂PAM的投入量为12mg／L，溶液pH值为4．0．温度为30℃，搅拌时间为10min时，对魔芋精粉湿法生产溶剂的回收达到最为满意的效果，酒精的回收率达到94．6％，蛋白（Pr）的去除率达到99．0％以上，化学需氧量（COD）的去除率达到92.0％，透光率达到99．0％以上。     

光叶楮白皮生物脱胶制浆及其机理研究

对影响光叶楮白皮生物脱胶制浆的主要因素及脱胶酶特性进行了研究。结果表明，生物脱胶制浆的最优工艺条件为：初始pH值7，温度30℃，液比1：15～1：25，接种量3％；加入氨源助剂能够显著提高成浆效果，且以用量为1．5％。2．5％的尿素为佳。最优条件下的制浆结果为：得率70．O％，高锰酸钾值14，6，白度43，2％ISO，成浆时间94h，废液pH值4．0，CODc。值为O．337L／t浆。脱胶酶活力分析结果表明：发酵初期，酶活力都随时间延长而升高，发酵至36h，果胶酶活力达到峰值，木聚糖酶活力在发酵至60h达到峰值，峰值过后，2种酶的活力随时间延长逐渐降低，纤维素酶活力在整个周期内缓慢增加，没有峰值出现。     

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.