油脂添加对冻融鱼糜凝胶结构和大变形行为的影响

研究大豆油添加(1%、3%、5%和7%)对冻融过程中鱼糜凝胶结构的影响，并采用一阶Ogden模型拟合添加不同质量分数豆油的鱼糜凝胶在大压缩变形(拉伸比为0.4～1)下的真实应力和真实应变之间的关系。结果表明，新鲜鱼糜中，大豆油的添加会降低鱼糜凝胶的凝胶强度，鱼糜凝胶网状孔隙变大；而6次冻融循环后，添加5%、7%的大豆油对鱼糜凝胶网络结构具有保护作用，凝胶强度(319.30、338.64 g·cm)显著高于空白样品(286.04 g·cm)(P<0.05)，其网络结构的完整性也优于后者。Ogden模型能够很好拟合添加了大豆油的新鲜鱼糜凝胶及冻融后样品的真实应力-应变压缩响应曲线(R²=0.916～0.998)；同时，模型拟合结果显示，新鲜鱼糜凝胶及冻融样品的初始剪切模量的变化与凝胶强度结果一致。本研究表明添加5%和7%的大豆油可以减缓低温冷冻-融化过程对鱼糜凝胶结构的破坏；Ogden模型能很好描述油脂添加对新鲜鱼糜及冻融后的凝胶大变形行为的影响，为实际生产中鱼糜制品的品质提升及运输贮藏条件的控制提供理论依据和技术支持。     

轻质高弹EVA复合发泡材料的制备及其性能研究

以乙烯-醋酸乙烯酯共聚物(EVA)为主基体，1,4-双叔丁基过氧异丙基苯(BIPB)和三烯丙基异三聚氰酸酯(TAIC)为交联体系，三元乙丙橡胶(EPDM)和苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物(SEBS)为弹性体改性剂，采用一次模压法制备了发泡EVA复合材料。研究了不同BIPB含量和弹性体改性剂种类对复合发泡材料交联行为、形貌结构、硬度、密度、回弹性、压缩永久变形的影响。结果表明，在一定范围内随着交联剂用量的增加，复合发泡材料最佳交联时间缩短，硬度和密度增大，回弹性先增大后降低，压缩永久变形变小；其中较优复合材料的密度为0.14 g/cm³,C型硬度为42,回弹性为62.5%,微观泡孔形貌特征为闭孔结构，平均孔径大小约130μm; EPDM和SEBS对回弹性的改善程度相近。     

菠罗果肉酸奶生产工艺的研制

以鲜牛奶和菠萝果肉为主要原料,以保加利亚乳杆菌与嗜热链球菌(11混合)为发酵剂,以白砂糖为调味剂,采取3种工艺流程,通过L.(3)正交试验确定出最佳工艺流程和工艺参数为鲜牛奶(250g)→加入白砂糖(25g)→过滤→杀菌(95℃,5min)→接入4%的发酵剂→43℃恒温发酵3h→加入灭菌菠萝果肉(37.5g)→混匀→后发醉(0～5℃,24h)→成品.以此工艺制备的菠萝果肉酸奶,不仅可以保持传统型酸奶的风味,并且有浓郁的菠萝风味,组织状态均匀,其货架期在0～5℃可达15～20天.     

大豆油脂肪酸溶剂法分提研究

研究溶剂法分提大豆油脂肪酸,该法能取得良好效果。具体条件是:脂肪酸60℃熔化后,加入脂肪酸质量1.5倍乙醇;然后从15℃开始,以5℃/h降温速度逐渐降温至–15℃,养晶4h,真空抽滤,将固体与液体分别脱除溶剂;分提得到液体脂肪酸中饱和酸含量为2%～3%,而固体中饱和酸含量为60.3%。     

沙发座垫用丝瓜络力学性能探究

为探究丝瓜络的承载方向对其压缩力学性能的影响,参考GB/T 10807—2006和GB/T 6669—2008试验标准,研究了丝瓜络柱段的承载方向对压陷硬度、压缩变形特征、形状回复率及压缩永久变形的影响,并将该材料与沙发常用海绵材料的相应性能进行了对比。结果表明:两种密度的丝瓜络材料的承载方向对其压陷硬度、压缩变形特征、24 h后形状回复率及压缩永久变形都有显著影响。研究结果可为设计以丝瓜络为填充材料的环保型座垫提供理论依据。     

固定化脂肪酶催化酯交换合成生物柴油研究

以苯乙烯为单体,二乙烯苯为交联剂,过氧化苯甲酞为引发剂,明胶为分散剂,采用悬浮聚合法制备St-DVB-CBA三元共聚高分子微球,将其作为固定化脂肪酶载体,通过共价结合法进行脂肪酶固定化,探讨固定化脂肪酶催化大豆油酯交换反应活性。实验结果表明:固定化脂肪酶在醇油摩尔比为3∶1,分三次加入;固定化酶加入量15wt.%(油重);反应时间24 h;反应温度40℃;正己烷加入量15wt.%(油重);水分含量4wt.%(油重);转化率最高,可达90.08%;固定化脂肪酶重复使用时显示出较好稳定性和催化活性。     

莜麦芽酸乳生产工艺的研制

研究了莜麦芽酸乳生产工艺.通过对照试验确定了用发芽0.9cm～1.0cm的莜麦芽制作的酸乳感官品质最佳.再通过对照试验和L9(34)正交试验确定了最佳工艺路线和参数为莜麦芽4g→开水20mL冲调→加入新鲜牛奶80mL和白糖8g→UHT灭菌→接入5%的发酵剂→42℃恒温发酵4.5h→后发酵(0℃～5℃)24h.产品质地均匀、口感细腻、具有莜麦的香味和奶香味,在0℃～5℃时的货架期为20d左右.     

血橙果酒生产工艺研究

通过研究,确定血橙果酒的生产工艺,为:血橙去皮榨汁后加入0.2 g/L葡萄酒活性干酵母,在24℃发酵5～7 d.糖度降至4%～6%;用4层纱布过滤发酵醪,继续发酵10～14 d后在5～10℃陈酿30 d;加入0.06%壳聚糖,吸附悬浮物72h,膜过滤、包装、灭菌得血橙果酒.血橙果酒为透明的红色、酸度适中、酒体醇厚、香气怡人,总糖(以葡萄糖计)含量48±6.5 g/L,pH4.0±0.52,总酸(以酒石酸计)6±2 g/L.     

新型红甜菜酸乳生产工艺的研制

以牛奶为主要原料,添加红甜菜汁等辅料,以保加利亚乳杆菌和嗜热链球菌为发酵剂,以白砂糖为调味剂,通过单因素试验及L9(34)正交试验确定出最佳工艺流程及工艺参数为:牛奶(100mL)和白糖(8g)→灭菌(121℃,5 s)→接入5%的发酵剂→42℃恒温发酵(5h)→加入4%的红甜菜汁→后发酵(0℃～5℃,24h).此产品不仅保留了酸奶风味清新、酸甜可口的特点,在0℃～5℃时的货架期为20d左右.     

菠萝果肉酸奶生产工艺的研制

以鲜牛奶和菠萝果肉为主要原料，以保加利亚乳杆菌与嗜热链球菌(1：1混合)为发酵剂，以白砂糖为调味剂，采取3种工艺流程，通过L9(3^4)正交试验确定出最佳工艺流程和工艺参数为：鲜牛奶(250g)→加入白砂糖(25g)→过滤→杀菌(95℃，5min)→接入496的发酵剂→43℃恒温发酵3h→加入灭菌菠萝果肉(37.5g)→混匀→后发醉(0-5℃，24h)→成品。以此工艺制备的菠萝果肉酸奶，不仅可以保持传统型酸奶的风味，并且有浓郁的菠萝风味，组织状态均匀，其货架期在0—5℃可达15～20天。     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.