挤压法钝化米糠脂肪水解酶效果研究

为了延长米糠保质期及增加米糠稳定性,采用挤压法研究米糠脂肪水解酶活性。运用单因素和旋转正交试验方法,以挤压温度、物料水分、螺杆转速和模头型号为参考因素,用频数选优法选出5组较佳参数组合,对比预测值和实测值,确定降低脂肪水解酶活性的最佳工艺参数,即:机筒温度137℃,物料含水率23%,螺杆转速130 r/min,模孔直径8 mm。此时脂肪水解酶酶活降至5.26%。     

相关参数对单螺杆挤压机耗电量影响的研究

研究了豆粕挤压膨化系统的相关参数(物料含水率、螺杆转速、机筒温度、模头长径比L/D)对耗电量的影响规律和挤压膨化系统最佳参数。试验结果表明,影响试验指标的主要因素是螺杆转速,试验影响因素主次排列为螺杆转速、模头长径比、物料含水率和机筒温度。其最优组合为转速337r/min、模头长径比7、物料含水率35%、机筒温度140℃。     

相关参数对单螺杆挤压机耗电量影响的研究

研究了豆粕挤压膨化系统的相关参数（物料含水率、螺杆转速、机筒温度、模头长径比L／D）对耗电量的影响规律和挤压膨化系统最佳参数。试验结果表明，影响试验指标的主要因素是螺杆转速，试验影响因素主次排列为螺杆转速、模头长径比、物料含水率和机筒温度。其最优组合为转速337r／min、模头长径比7、物料含水率35％、机筒温度140℃。     

挤压膨化机结构参数对豆粕吸水指数影响的研究

研究了豆粕挤压膨化系统诸参数(物料含水率、螺杆转速、机筒温度)对其吸水性指数的影响规律和挤压膨化系统最佳参数。试验结果表明,影响试验指标的主要因素是螺杆转速,试验因素主次排列为物料含水率、机筒温度、螺杆转速。其较优组合为物料含水率为17%、机筒温度为130℃、转速为305r/min。     

结构参数对单螺杆挤压机生产率影响的研究

研究了豆粕挤压膨化系统诸参数 (物料含水率、螺杆转速、机筒温度 )对生产率的影响规律和挤压膨化系统最佳参数。试验结果表明 ,影响试验指标的主要因素是螺杆转速 ,试验因素主次排列为 :螺杆转速、机筒温度、物料含水率。其较优组合为 :转速 335r/min、机筒温度 12 3℃、物料含水率 2 6 %。     

结构参数对单螺杆挤压机生产率影响的研究

研究了豆粕挤压膨化系统诸参数(物料含水率、螺杆转速、机筒温度)对生产率的影响规律和挤压膨化系统最佳参数。试验结果表明，主次排列为：螺杆转速、机筒温度、物料含水率。物料含水率26％。影响试验指标的主要因素是螺杆转速，试验因素其较优组合为：转速335r/min、机筒温度123℃。     

玉米蛋白粉挤压膨化工艺参数优化研究

以单螺杆挤压膨化机为试验设备对玉米蛋白粉进行膨化试验,运用二次通用旋转组合设计试验方法研究了玉米蛋白粉含水率、膨化机螺杆转速和机筒温度对加工后的玉米蛋白粉持水性的影响。结果表明:影响玉米蛋白粉持水性的主要因素是机筒温度,试验因素主次顺序依次为机筒温度、螺杆转速、物料含水率;较优组合为:物料含水率43%、螺杆转速334r/min、机筒温度157℃。     

正交法优化豆粕挤压膨化系统参数

研究了豆粕挤压膨化系统诸参数（物料含水率、螺杆转速、机筒温度）对各考察指标（产品的膨化指数,挤压机的生产率和功耗）的影响规律,并对其参数进行了优选。试验结果表明：影响试验指标的主要因素是螺杆转速,试验因素主次排列为螺杆转速、机筒温度、物料含水率。其较优组合为转速295 r/min、机筒温度130℃、物料含水率27%。     

单螺杆挤压机加工工艺参数的优化

对豆粕挤压膨化系统诸参数(物料含水率、螺杆转速、机筒温度)对成本的影响规律和挤压膨化系统最佳参数进行了研究.结果表明,影响实验指标的主要因素是螺杆转速,实验因素主次排列为螺杆转速、机筒温度、物料含水率.其较优组合为:转速295r/min、机筒温度130℃、物料含水率27%.     

挤压膨化机结构参数对豆粕吸水指数影响的研究

研究了豆粕挤压膨化系统诸参数（物料舍水率、螺杆转速、机筒温度）对其吸水性指数的影响规律和挤压膨化系统最佳参数。试验结果表明，影响试验指标的主要因素是螺杆转速，试验因素主次排列为物料含水率、机筒温度、螺杆转速。其较优组合为物料含水率为17％、机筒温度为130℃、转速为305r／min。     

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.