浓硫酸催化脱臭馏出物脂肪酸甲酯化工艺研究

通过改变甲醇用量、温度、时间、催化剂用量等各种条件对脂肪酸甲酯化过程进行控制。研究 表明:脱臭馏出物脂肪酸甲酯化适宜条件为:溶剂:原料(V／w)=1.1:1;甲酯化时间:2小时;甲酯化 温度:60℃;催化剂:原料(V／W)=0.01:1,在该条件下,脂肪酸甲酯化率达到98％。     

皂脚制备生物柴油的研究

介绍了以皂脚为原料制备生物柴油的方法,反应以H2SO4为催化剂,通过将皂脚转化为脂肪酸,然后与甲醇进行酯化反应获得脂肪酸甲酯。分别考察了酯化反应条件如反应温度、反应时间、甲醇与脂肪酸的比例对酯化率的影响。应用正交实验方法得出酯化反应的最佳条件为:反应温度60℃,反应时间60 min,甲醇与脂肪酸的比例为1∶1(V/W)。     

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%.     

响应面法优化超声波辅助猪油酯交换反应制备生物柴油的研究

以猪油和甲醇为原料,KOH为催化剂,采用单因素法确定醇油摩尔比、超声波功率、催化剂用量、反应温度等因素对猪油酯交换反应的脂肪酸甲酯产率的影响。单因素实验结果显示各因素的最佳值分别为醇油摩尔比6∶1,超声波功率为120 W,催化剂用量为0.8%,反应温度为60℃。采用响应面分析法优化超声强化KOH均相碱催化酯交换条件,结果显示最优条件为:醇油摩尔比为5.8∶1,超声功率为135.91W,反应温度为52.78℃,催化剂用量为0.86%,在该条件下甲酯最大的理论转化率为99.53%。     

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%。     

脲包法富集高纯度红花油亚油酸甲酯的研究

以亚油酸含量 81 74 %的红花油为原料 ,采用先碱性醇解 ,后尿素包合的方法 ,从红花油中富集亚油酸。通过正交试验 ,确定了尿素一次包合法富集高纯度亚油酸甲酯的最佳工艺条件 :混合脂肪酸甲酯∶尿素∶甲醇为 1 0 4∶1∶4 (W/W /V) ,包合温度 - 10℃ ,包合时间 2 4h ,亚油酸甲酯得率 72 95 % ,纯度 99 2 7%。     

脱臭馏出物提取VE的酶预处理

研究了以大豆油脱臭馏出物为原料,采用脂肪酶Novozym435为催化剂,催化脂肪酸与甲醇的酯化反应。反应最佳工艺条件为:反应试剂摩尔比(甲醇∶脱臭馏出物中游离脂肪酸)为2.2∶1,催化剂用量为2.5%,反应温度为35℃,反应时间为10 h。在最佳反应条件下酯化率为95.9%。     

微波辅助绿豆碳基固体酸催化剂活性研究

为了考察微波辐射对自制固体酸催化剂催化活性的影响,作者以绿豆为原料,采用碳化-磺化法制备了一种新型碳基固体酸催化剂,于实验室自制微波反应器中催化油酸和甲醇的酯化反应。对油酸甲酯化反应过程中的微波功率、反应温度、反应时间、催化剂用量、醇油摩尔比等条件进行了单因素分析,并对醇油摩尔比、反应时间、催化剂用量对油酸甲酯化的转化率的影响进行了正交优化,得到最佳工艺为:微波功率400 W、反应温度65℃、醇油摩尔比11∶1、反应时间30 min、催化剂用量为5%,在此工艺条件下油酸甲酯化的转化率为93.97%。     

无溶剂法合成食品添加剂菜籽油蔗糖酯的研究

在碱催化条件下,先由甲醇和菜籽油反应制得脂肪酸甲酯.然后以脂肪酸甲酯和蔗糖为原料,在催化剂和乳化剂的作用下进行酯交换反应合成了蔗糖脂肪酸酯.详细考察了反应过程中乳化剂及催化剂用量,反应时间,反应温度,酯糖比,压力等因素对合成蔗糖酯产率的影响.确定了最佳的合成工艺条件,即乳化剂用量为反应物总质量的9%,催化剂用量为7%,反应温度130℃,反应时间5h,n(脂肪酸甲酯)∶n(蔗糖)=3∶1,压力4.45KPa.该条件下,菜籽油蔗糖酯的产率可高达72.4%,其临界胶束浓度(CMC)为1.86g/L,表面张力为29.4mN/m,乳化力为122s,亲水性能为9.86mL,HLB值为11.5.     

H9P2W15V3/C催化绿色合成对羟基苯甲酸丁酯

以活性碳为载体,通过浸渍法制备了H9P2W15V3/C催化剂,对催化剂进行Uv-Vis、FT-IR表征。以对羟基苯甲酸丁酯的合成反应为探针,考察了催化剂的催化性能。研究了磷钨钒杂多酸负载量、催化剂用量、醇酸比、反应时间和反应温度对反应的影响。通过单因素实验和正交实验确定了反应的最佳条件:杂多酸负载量为30%,催化剂用量8.7%(按反应体系总质量计算),醇酸摩尔比2∶1,反应时间3h,反应温度125℃,酯化率可达91.30%。催化重复使用5次,酯化率仍可达76.42%。     

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.     

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.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the