挤压非膨化制作鱼肉面条工艺研究

为开发鱼肉面条产品,应用双螺杆挤压机对挤压非膨化制面技术进行了研究。鱼肉面条的最佳添加配比为：白鲢鱼糜25%、水6%、海藻酸钠0.3%﹑马铃薯醋酸酯化淀粉2.5%﹑食盐2%。双螺杆挤压机最佳工艺参数为主电机转速80r/min﹑一区温度60℃﹑二区温度85℃﹑三区温度110℃。生产出的鱼肉面条营养丰富,口感爽滑,具有独特的鱼肉风味。     

大豆蛋白和鱼肉复合挤压工艺参数的优化研究

以大豆蛋白和鱼肉糜为原料,通过双螺杆挤压机制备复合蛋白产品。通过单因素实验,对复合蛋白物料含水率、螺杆挤压机的机筒五区温度、喂料速度以及螺杆转速进行考察,最后通过响应面设计优化得到最佳工艺参数。得到的最佳工艺参数为:物料含水率30%,喂料速度35 r/min,螺杆转速175 r/min,挤压机机筒五区温度为90℃→100℃→110℃→145℃→110℃。在最佳工艺参数条件下生产出的挤压产品指标为:组织化程度2.12,拉伸强度3 224.6 g,蛋白质含量67.9%,粗脂肪含量1.56%,蛋白质体外消化率87.4%。     

挤压法制备米糠膳食纤维的研究

研究了利用挤压法提高米糠中可溶性膳食纤维的含量,结果表明,双螺杆挤压最佳工艺条件为挤压温度150℃、物料水分17.5%、螺杆转速150r/min,可溶性膳食纤维的含量为15.58%;并且双螺杆挤压机的挤压效果大大优于单螺杆挤压机,同时探讨了可溶性膳食纤维增加的来源。     

大豆蛋白和鱼肉复合挤压工艺参数的优化

以新鲜淡水鱼鱼糜为原料,与大豆蛋白(大豆分离蛋白、大豆凝胶蛋白、低变性豆粕粉)混合进行复合挤压,利用双螺杆挤压机生产鱼肉与大豆蛋白复合食品,该方法能极好的利用淡水鱼资源与大豆蛋白资源,降低鱼肉食品的生产成本,增加食品营养,拓展了鱼糜食品的加工途径。选取物料含水率、原料配比、挤压温度、螺杆转速、喂料速度等进行综合评价测定,得出挤压产品的最佳工艺条件。研究表明,复合鱼肉蛋白食品挤压工艺的最佳条件为:物料含水率30%~40%,四区温度125~135℃,喂料速度35~40r/min,螺杆转速165~170r/min。     

荞麦和玉米面条挤压生产工艺探讨

试验采用德国Brabender食品仪器公司实验室双螺杆挤压膨化机，研究样品水分含量和挤压温度对荞麦面条及玉米面条挤压工艺参数的影响。结果表明：在试验设计范围内，挤压温度和样品水分含量对荞麦面条和玉米面条的挤压工艺参数(扭矩和压力)及蒸煮品质均有影响。样品水分含量30％，挤压温度为80-85-90-95℃的玉米面条，样品水分含量28％，挤压温度为45-50-55-60℃的荞麦面条蒸煮品质最好。挤压机夹套温度对挤压工艺参数有显著影响：随着挤压机夹套温度升高，达到淀粉最大糊化温度时，物料粘度大增，扭矩和压力也随之增大。     

膨化大豆组织蛋白挤压工艺对其吸水性的影响

组织蛋白成品质量的好坏,尤其是吸水性直接与双螺杆挤压机的工艺操作条件相关。以大豆分离蛋白、谷朊粉、脱脂脱腥大豆蛋白等混合物料为原料,以双螺杆挤压机(FMHE 36-24)为设备,研究了模头温度、液体喂料量、固体喂料量、螺杆转速对产品吸水性的影响。结果表明:挤压工艺参数对低水分大豆组织蛋白吸水性影响程度大小依次为:模头温度液体喂料量固体喂料量螺杆转速。生产低水分大豆组织蛋白的最佳工艺参数为:模头温度160℃,液体喂料量30%,固体喂料量35 kg/h,螺杆转速350 r/min,此条件下吸水率为432.68%。     

限制性糊化糙米粉的挤压工艺参数研究

以双螺杆挤压机为实验设备,以糙米为主要原料,在重组糙米成型的前提下,研究了物料水分、机筒温度、螺杆转速对重组糙米糊化度的影响。利用单因素试验和正交试验确定限制性糊化糙米重组米的最佳工艺参数为:机筒温度110℃、物料水分35%、螺杆转速140r/min。在该工艺条件下,重组糙米糊化度为89.79%。     

燕麦方便面的非膨化挤压生产技术

采用DSC、布拉班德粉质仪和双螺杆挤压机研究燕麦方便面的非膨化挤压生产工艺,具体分析燕麦粉添加量、混粉水分含量、螺杆转速、机筒温度对方便面糊化度和复水性的影响。结果表明,非膨化挤压生产燕麦方便面的较佳工艺条件为燕麦粉添加量40%(燕麦粉与混粉的质量比)、混粉水分含量40%、螺杆转速210r/min,以及机筒温度Ⅱ区90～95℃、Ⅲ区110～115℃。在此工艺条件下制得燕麦方便面的糊化度为94.6%、复水时间为8min。     

糙米意大利面的制备

以粳/籼糙米混合粉质量比(1∶1)为基本原料,加8%的大豆分离蛋白,采用双螺杆挤压技术优化了糙米意大利面的制备工艺。实验中,采用单因素试验和正交试验相结合的方法,研究了双螺杆挤压机挤压参数和添加剂对糙米意大利面蒸煮品质和质构的影响。结果表明:双螺杆挤压机的最佳工艺参数为,原料初始水分调12%,加水量28%,三区四区挤压温度120℃、螺杆转速120 r/m、喂料速度8 kg/h;优化后添加剂的复配添加量(糙米粉干基计)为,瓜尔胶0.4%、海藻酸钠0.4%、黄原胶0.4%、单硬脂酸甘油酯0.8%;此优化条件下,所制备的糙米意大利面与市售意大利面相比较(煮8 min),蒸煮损失为6.54%,与市售意大利面相当(6.51%);硬度为2 597.34 g,稍大于市售意大利面的硬度(2 365.56 g);表面黏附性为-7.53 g·s,稍小于市售意大利面的表面黏附性(-7.89 g·s)。     

BP人工神经网络在鱼糜挤压制品生产中的应用

采用反向传播(BP)人工神经网络和响应面法(RSM)模拟操作工艺参数(鱼糜含量、螺杆转速、III区加热温度)对双螺杆挤压机生产的鱼糜挤压制品的品质属性(持水性、膨润度、硬度和弹性)的影响,并比较了BP人工神经网络和RSM所建立的操作工艺参数与产品属性间关系模型的预测误差。试验结果表明,经训练的BP人工神经网络的模拟值和实际值的均方差(MSE)及和方差(SSE)均比RSM低,在模拟产品属性上具有更好的拟合度和准确性,采用此法确定的鱼糜挤压制品最佳工艺参数为:鱼糜含量45.70%,螺杆转速170r/min,III区温度106.2℃。     

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.