固体酸催化大豆油脱臭馏出物甲酯化工艺研究

采用溶胶-凝胶和浸渍法制备了SO2-4/TiO2-SiO2固体酸催化剂,利用其对大豆油脱臭馏出物进行甲酯化。研究了TiO2-SiO2载体焙烧温度、浸渍用硫酸浓度、浸渍时间对催化剂活性的影响,以及催化剂用量、醇油比、反应温度和反应时间对酯化率的影响。得到了最佳反应条件为载体焙烧温度550℃,浸渍用硫酸浓度2.5 mol/L,浸渍时间12 h,催化剂用量5%(以大豆油脱臭馏出物质量计),醇油比1.5∶1(甲醇与大豆油脱臭馏出物体积质量比),反应温度65℃,反应时间4 h。在最佳条件下,酯化率达到96.5%。     

大豆油脱臭馏出物预酯化工艺研究

通过单因素试验,对豆油脱臭馏出物的最佳预酯化工艺进行研究,得到最佳工艺:醇油比为12∶1,催化剂含量为1.0%,温度50℃,反应100min。在该条件下,验证试验表明,豆油脱臭馏出物的酸价可以降低至8.5mgKOH/g。     

大豆油脱臭馏出物中同时提取角鲨烯、生育酚和植物甾醇的工艺研究

采用酯化—高真空蒸馏工艺路线,从大豆油脱臭馏出物中同时提取角鲨烯、生育酚及植物甾醇。考察酯化条件(甲醇、催化剂浓硫酸用量及反应时间)对酯化率、角鲨烯和生育酚含量的影响。优化得到的最佳工艺为:催化剂浓硫酸添加量0.5%,醇油摩尔比10∶1,反应温度70℃,反应时间120 min,大豆油脱臭馏出物酯化率达到98.2%,生育酚和角鲨烯保留率分别为97.7%和97.5%。酯化后的物料通过冷析结晶,抽滤得到植物甾醇粗品,滤液高真空蒸馏,初步分离得到脂肪酸甲酯、角鲨烯、生育酚等组分。各组分中角鲨烯富集到12.2%,生育酚富集到28.6%,植物甾醇富集到60%左右,初步实现了大豆油脱臭馏出物中角鲨烯、生育酚、植物甾醇的同时提取,为角鲨烯、生育酚及植物甾醇的进一步富集提供了参考依据。     

大豆油脱臭馏出物酶法甲酯化工艺研究

Eversa Transform 2. 0脂肪酶价格低、催化活性好,具有微量高效的优点。以Eversa Transform2. 0脂肪酶为催化剂,对大豆油脱臭馏出物进行酶法甲酯化工艺研究。通过单因素试验研究了醇酸摩尔比、酶用量、反应温度、反应时间对酯化率的影响,并进行正交试验,对酶法甲酯化工艺进行优化。在最佳工艺条件下,通过放大试验对试验结果进行验证,并采用薄层色谱法对甘油三酯的转化进行分析。结果表明:Eversa Transform 2. 0脂肪酶催化大豆油脱臭馏出物甲酯化反应的最佳工艺条件为醇酸摩尔比(甲醇与游离脂肪酸摩尔比) 2∶1、酶用量0. 3%(相对于大豆油脱臭馏出物的质量)、反应温度35℃、反应时间6 h,在此条件下酯化率达到95%以上,且甘油三酯基本反应完全。     

双低菜籽油脱臭馏出物提取天然VE的酯化工艺研究

探讨了从双低菜籽油脱臭馏出物中提取天然VE的酯化工艺条件,依据正交实验确定了第一次酯化的最佳工艺参数为:馏出物:甲醇(W/V)10:9,酯化温度60℃,酯化时间2 h;第二次酯化的最佳工艺参数为:甘油酯:甲醇(摩尔比)1:6,催化剂用量1.0%,酯化温度45℃,酯化率98.9%.     

棕榈油脱臭馏出物的甲酯化工艺研究

研究了棕榈油脱臭馏出物甲酯化反应的最佳条件,以利于后续提取天然VE。通过单因素试验考察醇油摩尔比、催化剂用量、反应时间及反应温度对甲酯化反应的影响,并采用正交试验对反应条件进行优化。结果表明,棕榈油脱臭馏出物甲酯化反应最佳工艺条件为:醇油摩尔比7.5∶1,催化剂用量1.5%,反应温度70℃,反应时间45 min。在最佳工艺条件下,棕榈油脱臭馏出物甲酯化率达到96.7%。真空蒸馏后,棕榈油脱臭馏出物甲酯化产物中天然VE含量从1.26%提高到8.20%。     

棉籽油脱臭馏出物中脂肪酸甲酯化工艺研究

棉籽油脱臭馏出物中含有40%-80%的游离脂肪酸,对这部分脂肪酸的甲酯化进行了研究。考察了甲醇用量、催化剂用量、酯化温度、酯化时间对脂肪酸甲酯化的影响。结果表明,脂肪酸甲酯化优化条件为甲醇/原料为2∶1(V/W),催化剂/原料为0.005∶1(V/W),酯化温度65℃,酯化时间3 h;在此条件下脂肪酸甲酯化率达到98%以上。     

响应面法优化生物酶法催化脱臭馏出物甲酯化

为实现脱臭馏出物绿色、清洁、高效甲酯化,达到环保生产的目的,通过单因素实验和响应面实验对生物酶法催化脱臭馏出物甲酯化反应的工艺条件进行了优化,测定了反应前后维生素E含量的变化,并将新工艺应用于实际生产线。结果表明：生物酶法催化脱臭馏出物甲酯化的最佳反应条件为加水量1%(以脱臭馏出物质量计)、甲醇用量11.5%(以脱臭馏出物质量计)、固定化脂肪酶用量0.3%(以脱臭馏出物质量计)、反应温度35.6℃,在最佳条件下反应8 h脱臭馏出物中游离脂肪酸酯化率达到92.59%,甘油酯酯化率达到94.95%;生物酶法催化脱臭馏出物甲酯化反应过程中维生素E损失少,收率达到93%;与浓硫酸催化甲酯化工艺相比,产品维生素E(50%维生素E)总收率提高了3.47百分点,植物甾醇总收率提高了3.26百分点。综上,生物酶法催化脱臭馏出物甲酯化,可以得到较高的酯化率,提高了产品维生素E和植物甾醇收率。     

从大豆油脱臭馏出物中制备维生素E的工艺研究

研究采用酯化—蒸馏工艺 ,从大豆油脱臭馏出物中制备维生素E的方法。实验结果表明 ,最佳的工艺条件为 :馏出物∶甲醇 (w/v) 10∶10 ,冷析温度 :0℃ ,酯化时间 :2h。该工艺可使馏出物中维生素E的含量从 3 3%提高到 9 4 8% ;若采用 95 %乙醇进一步萃取可使维生素E含量提高到 12 4 9%。     

新疆棉籽油脱臭馏出物酶法甲酯化工艺研究

以新疆棉籽油脱臭馏出物为研究对象,采用Novozyme435脂肪酶催化其中的游离脂肪酸进行甲酯化反应,通过单因素试验对影响酯化反应的反应温度,反应时间,酶用量及酸醇比4个因素进行优化,选取最佳的工艺参数。在单因素试验的基础上应用响应面设计确定最优的棉籽油脱臭馏出物脂肪酸甲酯化反应的工艺参数。结果表明,棉籽油脱臭馏出物甲酯化最优工艺条件是反应温度60 ℃,酶用量62.86 plu/g,反应时间9 h和酸醇比1.00∶1.65（g∶mL）,模型预测酯化率97.27%,实际试验值为（97.09±0.09）%,基本与预测值一致。     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.