动态滤水实验方法的探讨

对动态滤水实验方法进行了初步的研究,结果表明,①动态滤水实验所用试样浓度以０２％～０３％为宜;②比色法是一种快速、可取的动态滤水实验的滤液浓度的测定方法;③在未使用助留剂的情况下,苇浆试样的“单点法”动态滤水实验的搅拌速度以３００ｒ／ｍｉｎ为佳;木浆试样以５００ｒ／ｍｉｎ为佳;④当考察造纸化学助剂的助留效果时,苇浆试样的“单点法”动态滤水实验的搅拌速度以３００～６００ｒ／ｍｉｎ为佳;木浆试样的搅拌速度可在５００～１０００ｒ／ｍｉｎ的范围内选择。     

耐碱性芽孢杆菌碱性淀粉酶的研究──发酵试验与酶的性质

本文报道碱性α－淀粉酶１４Ｌ罐发酵工艺及其酶的性质。发酵过程中，当搅拌转速为４００ｒ／ｍｉｎ，通风比为１：１．２５Ｌ／（Ｌ·ｍｉｎ），发酵周期４４ｈ，酶活力可达７４０ｕ／ｍｌ。采用有机溶剂沉淀法提取酶，回收率可达９０％。Ｃａ￣（２＋）对酶活性无影响，ＥＤＴＡ对酶有激活作用。酶样保存半年，活力损失小于１５％。     

耐碱性芽孢杆菌碱性淀粉酶的研究

本文报道碱性α－淀粉酶１４Ｌ罐发酵工艺及其酶的性质。发酵过程中，当搅拌转速为４００ｒ／ｍｉｎ，通风比为１：１．２５Ｌ／（Ｌ．ｍｉｎ），发酵周期４４ｈ，酶活力可达７４０ｕ／ｍｌ。采用有机溶剂沉淀法提取酶，回收率可达９０％。Ｃａ＾２＋对酶活性无影响，ＥＤＴＡ对酶有激活作用。酶样保存半年，活力损失小于１５％。     

脂肪酶催化动物脂肪水解

研究了脂肪酶ＬｉｐｏｌａｓｅＴＭ催化猪油和牛羊油水解的工艺条件。试验结果表明，适宜的工艺条件是：ｐＨ值８．０，温度５０℃（猪油）或５５℃（牛羊油），底物浓度５１％（Ｗ／Ｖ），搅拌速度４５０ｒ／ｍｉｎ～５００ｒ／ｍｉｎ，酶用量１５０Ｕ／ｇ油脂。在上述条件下水解２４ｈ，水解率＞９５％。     

浅谈汽车废旧齿轮的再利用

我厂是一个生产糖、酒、纸的综合企业。因工艺需要，各种搅拌设备较多，其搅拌减速装置的好坏直接影响生产的正常进行。１问题的提出造纸分厂液氯制漂岗位两台化漂搅拌以前用带传动与圆锥齿轮传动两级减速满足搅拌转速５０ｒ／ｍｉｎ的要求。近年来圆锥齿轮及三角带磨损、腐蚀严重，更换频繁，甚至出现每二至三天更换一次三角带，一年内更换一至二次圆锥齿轮的严重状况，彻底改造搅拌减速装置已刻不容缓。２分析研究与改进措施通过分析，造成这种状况的主要原因是：１）环境相对较差，腐蚀严重。２）设计上，传动比分配不合理，结构不紧凑；…     

江苏星轮高速机电设备制造公司产品简介

江苏星轮高速机电设备制造公司产品简介该公司是生产高速电机、高速机械的专业制造公司。高速电机、高速机械为机电一体化高科技产品。高速电机及变频调速电源已形成转速１～３０万ｒ／ｍｉｎ、功率０．０５～３０ｋＷ的系列产品，其中ＧＷ９５—１数控钻用高速电机获市优...     

苦荞麦营养粉挤压膨化的工艺参数及配方优化

利用ＱＰＳ６５×２型双螺杆菌挤压膨化机对苦荞麦营养成分与其他粉料（籼稻大米粉，糯发，面粉）的配比及挤压螺杆转速，进料量，套筒温度（后三段）等参数进行了研究，结果表明在苦荞麦营养粉与籼稻大米粉比例为８０：２０，螺杆转速为３００ｒ／ｍｉｎ，进料量为４５０ｇ／ｍｉｎ，温度为１４０℃时，制得膨经效果最好的制品。     

化学发泡法挤出PE低发泡材料研究

采用化学交联、化学发泡法挤出了低发泡ＰＥ棒材．研究发现,当口模温度为１７０℃左右、螺杆转速为５５ｒ／ｍｉｎ～６４ｒ／ｍｉｎ时,熔体的黏度、弹性适合发泡;而当每１００ｇＰＥ中,ＡＣ用量为２ｇ,ＤＣＰ用量为０．２ｇ～０．４ｇ,ＺｎＯ＋Ｚｎ（Ｓｔ）２用量为２ｇ时,可以得到外观光滑、手感好、泡孔细密的ＰＥ低发泡材料．     

花生油黄曲霉毒素的简易去除法

花生油黄曲霉毒素的简易去除法泰国于１９９３年２月实验成功一种去除花生油中黄曲霉毒素的简易方法，即用０．３％的漂白土与花生油混合，以每１５０ｒ／ｍｉｎ的速度搅拌１５ｍｉｎ，即可将黄曲霉素的含量由７６×１０－９降至７．８５×１０－９，低于泰国公共卫生部部...     

E7/5系列精梳机变频技术改造

１ 问题的提出 Ｅ７／５型及Ｅ７／５ Ａ型精梳机的主传动电机设计为双速子母电机。而双速子母电机的机械结构较为复杂，由两个单独的电机通过齿轮箱连接在一起，其高速电机的锥形转子经常发生轴向窜动，容易造成机械及电气故障。我公司现有Ｅ７／５型精梳机５台，Ｅ７／５Ａ型精梳机６台，部分原装进口子母电机由于机械部分磨损严重而报废，公司从国内某电机厂定做的７台双速子母电机，目前也开始频繁出现故障，直接影响了生产的正常进行。 我公司的Ｅ７／５（Ｅ７／５Ａ）型精梳机，根据其工艺要求，主传动电机的点动速度很低，只有 １８６ ｒ／ｍｉｎ，以便于生头；而高速运转时速度为 １４００ ｒ／ｍｉｎ，井且要求在停车时进行紧急制动停车。为达到这样的工艺要求，Ｅ７／５（Ｅ７／５ Ａ）型精梳机的主传动电机选用的是双速子母电机，子母电机的结构见图１。 该子母电机由两个单独的电机刚 和ＭＺ）通过齿轮箱连接在一起，从高速电机Ｍ互的轴头输出功率，其中高速电机ＭＩ的转速为１４００ ｒ／ｍｉｎ，低速电机ＭＺ转速为 １３１０ ｒ／ｍｉｎ，在低速运行时，低速电机ＭＺ转动，通过齿轮箱与高速电机ＭＩ连接，从ＭＩ的轴头输出转速为 １８６ ｒ／ｍｉｎ的功率；在高速运行时，...     

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.     

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.     

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.     

Detection of adulteration of locust bean gum with guar gum by capillary electrophoresis and polarized light microscopy

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.