响应面法优化大豆油脂肪酸乙酯合成工艺

以大豆油为原料,KOH作催化剂,通过大豆油与乙醇的酯交换反应合成了大豆油脂肪酸乙酯。应用响应曲面分析法中的Box-behnken模型对影响大豆油脂肪酸乙酯转化率的四个主要因素（催化剂用量、醇油摩尔比、反应温度、反应时间）进行了优化。研究表明大豆油脂肪酸乙酯的最佳合成工艺条件为：KOH用量1.3%,醇油比8.3∶1,反应温度74.8℃,反应时间130min。在此条件下,酯转化率达98.93%。     

聚能式逆流超声强化制备脂肪酸乙酯工艺研究

以大豆油脱臭馏出物为原料,通过聚能式逆流超声强化与乙醇反应制备脂肪酸乙酯。分析醇油体积比、反应温度、超声功率、催化剂用量和反应时间对脂肪酸乙酯转化率、得率、含量和生物柴油转化率的影响。通过正交实验优化得到:脂肪酸乙酯转化率最优工艺条件为醇油体积比20∶1,反应温度35℃,超声功率300 W,催化剂用量1.6%,反应时间30 min;脂肪酸乙酯得率最优工艺条件为醇油体积比30∶1,反应温度40℃,超声功率600 W,催化剂用量1%,反应时间30 min;脂肪酸乙酯含量最优工艺条件为醇油体积比20∶1,反应温度40℃,超声功率600 W,催化剂用量1%,反应时间60 min;生物柴油转化率最优工艺条件为醇油体积比25∶1,反应温度35℃,超声功率500 W,催化剂用量1%,反应时间30 min。     

对甲苯磺酸催化制备脂肪酸丁酯工艺研究

以对甲苯磺酸(PTS)为催化剂,大豆油和正丁醇为原料进行酯交换反应制备脂肪酸丁酯。考察醇油摩尔比、催化剂用量、反应温度以及反应时间对大豆油酯交换率的影响。结果表明,最佳合成工艺条件为:n(醇)∶n(油)=7.3∶1,w(PTS)=5%(以大豆油和正丁醇的总质量计),反应温度130℃,反应时间4.5h,在此条件下,酯交换率可达到89.4%。     

大豆油脂肪酸乙酯的制备及其在印刷油墨中的应用

以大豆油为原料,在催化剂KOH作用下,探讨大豆油与乙醇进行酯交换反应工艺,并对大豆油脂肪酸乙酯在印刷领域的应用进行论述。研究表明,在乙醇用量超过理论计算值的65％,催化剂用量为油重1．3％,反应时间2h,反应温度76-77℃条件下,酯交换反应转化率可达98．67％,且产物黏度和相对分子质量接近矿物油水平。其优异的溶解性能,安全的生产工艺和环保特性,表明大豆油脂肪酸乙酯在油墨中的应用潜力。     

正交法探讨制备生物柴油的优化条件

报道了大豆油在NaOH为催化剂的作用下通过甲醇酯交换反应生成脂肪酸甲酯即生物柴油的试验研究。考察了反应条件如醇油比、催化剂用量、反应温度、反应时间等的变化对生物柴油得率的影响。应用正交实验的方法找出大豆油酯交换反应的最佳反应条件为:反应温度40℃,醇油物质的量比6∶1,催化剂用量0.8%,反应时间60 m in。在此反应条件下生物柴油得率可达99.2%。实验所得的生物柴油主要质量指标已达到德国D INV51.606生物柴油质量标准。     

奇亚籽油脂肪酸乙酯的制备工艺研究

以奇亚籽油为原料,采用碱催化法制备奇亚籽油脂肪酸乙酯。对比甲醇钠、乙醇钠和氢氧化钠的催化效果,并通过单因素实验和正交实验优化奇亚籽油脂肪酸乙酯制备的工艺参数。结果表明：采用氢氧化钠为催化剂,乙酯含量和得率均最高;当酯交换温度为80 ℃、酯交换时间为1.5 h、醇油摩尔比为9∶ 1、氢氧化钠用量为油质量的0.6%时,奇亚籽油脂肪酸乙酯含量可达到89.01%。     

三七多糖的微生物发酵提取工艺优化及其抗炎功效评价

以精炼紫苏油为原料,在NaOH催化下与乙醇进行酯交换反应制备紫苏油脂肪酸乙酯。在分析碱性催化剂存在下油脂与乙醇酯交换原理基础上,采用逐滴滴加NaOH乙醇溶液,反应结束后加入等摩尔的盐酸两种工艺处理方式,克服因皂化物导致产品分离困难的技术问题。通过单因素试验和正交试验,对酯交换反应进行优化,结果表明,其最佳工艺条件为:反应温度75℃、反应时间2 h、NaOH用量0.8%、醇油摩尔比6∶1,在此条件下,紫苏油转化率达96%。     

高酸值鱼油两步法制备鱼油乙酯的研究

以高酸值鱼油脂肪酸甘油酯为原料,采用两步法制备鱼油脂肪酸乙酯.先以浓硫酸做催化剂,与乙醇进行预酯化反应;再以KOH做催化剂,进行酯交换反应.通过正交实验得到最优反应条件如下:预酯化反应:反应温度70℃,浓硫酸浓度1.5％,反应时间1h;酯交换反应:反应温度70℃,KOH浓度0.5％,反应时间0.5h.最优实验条件下,乙酯得率为92.5％.     

石榴籽油脂肪酸乙酯化工艺研究

以石榴籽油为原料、无水乙醇为反应物,在碱性催化剂氢氧化钠的作用下,对石榴籽油进行脂肪酸乙酯化工艺研究。在单因素实验的基础上,利用正交实验优化乙酯化工艺条件。结果表明:最优乙酯化工艺条件为反应温度75℃、反应时间2 h、醇油摩尔比8∶1、催化剂用量0.5%(以石榴籽油质量计),在该条件下乙酯含量可达95.88%。     

鸦胆子油的乙酯化工艺研究

以鸦胆子油为原料,无水乙醇为反应物与溶剂,对鸦胆子油的乙酯化工艺进行研究。通过单因素实验与正交实验,确定鸦胆子油乙酯化反应的最优条件为:选择甲醇钠为催化剂,催化剂用量0.6%(以鸦胆子油质量计),醇油摩尔比6∶1,反应温度75℃,反应时间2 h。在最优工艺条件下,鸦胆子油脂肪酸乙酯得率为92.38%。     

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.     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.