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。     

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%。     

番茄籽油脱臭馏出物中天然维生素E提取工艺的研究

选取番茄籽油脱臭馏出物为原料,采用无水乙醇皂化和正己烷萃取相结合的方法进行了脱臭馏出物中天然维生素E提取工艺的研究。响应面分析结果表明,最优条件为番茄籽油脱臭馏出物10.00 g、无水乙醇15 mL、NaOH 0.20 g、皂化温度75℃、皂化时间1 h,在该条件下,天然维生素E的提取率可达56.14%,该值与模型理论预测值接近。     

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。     

基于人工神经网络的菜籽油脱臭馏出物甲酯化响应曲面模型研究

以菜籽油脱臭馏出物为原料利用分子蒸馏分离维生素E和甾醇,原料的甲酯化是重要步骤之一。本文将人工神经网络与传统的单因素实验、旋转实验相结合,以人工神经网络代替一般响应曲面的多项式函数,利用神经网络特有的自学习能力,建立了菜籽油脱臭馏出物甲酯化过程的神经网络模型。并通过仿真,评估和优化,获得了菜籽油脱臭馏出物甲酯化处理的最佳工艺。当甲醇/原料:100ml/100g,反应时间:1.4hrs,催化剂/原料:4%,温度:60℃,此时甲酯化物酸价较低,对后续甾醇和维生素E分离提供了条件。     

酶法提取番茄籽油脱臭馏出物中维生素E的研究

试验以番茄籽油脱臭馏出物为原料,以脂肪酶为催化剂,通过酶法甲酯化,再将甲酯化产物结晶,分离甾醇后用正己烷提取维生素E的相关工艺及参数进了行研究。试验确定脂肪酶最佳反应体系为水相体系,结合响应面优化试验,确定最佳反应条件:料液比1︰5(mg/m L)、酶用量500 U/g、反应温度40℃、反应时间16 h和水分含量为26%时,番茄籽油脱臭馏出物中维生素E总提取率可以达到42.78%,与模型理论预测值43.45%接近。     

玉米油脱臭馏出物酶法甲酯化的研究

以固定化脂肪酶Novozym 435为催化剂,以叔丁醇为反应体系的溶剂,催化玉米油脱臭馏出物中的脂肪酸进行甲酯化反应,确定最佳反应条件。结果表明,脂肪酶添加量为80 mg/g,反应温度55℃,反应时间为20 h,醇料比为1.5∶1,叔丁醇添加量为6%,此时酯化率可达到96.84%。每次反应后的脂肪酶用丙酮处理,可循环使用7次,活性无明显降低。     

微生物发酵法预处理植物油脱臭馏出物

研究了一种新的植物油脱臭馏出物预处理方法即微生物发酵法。首先筛选出了能代谢利用脂肪酸的热带假丝酵母1253,然后使用该酵母发酵大豆油脱臭馏出物。在发酵过程中,随着菌体的生长,脱臭馏出物中脂肪酸被代谢消耗,提高了其中植物甾醇的含量,成功地实现了脱臭馏出物的浓缩。大豆油脱臭馏出物的适宜发酵培养基为:脱臭馏出物40g/L,尿素1.0g/L,MgSO40.1g/L,K2HPO40.2g/L,KH2PO40.2g/L。将热带假丝酵母1253接种到上述培养基中,30℃、200r/min摇床发酵96h,脱臭馏出物中脂肪酸消耗率达到70.21%,其中的植物甾醇含量由起始的15.2%提高到了28.43%。微生物发酵法预处理脱臭馏出物是一种技术上可行的、替代甲酯化预处理的方法。     

超临界CO_2萃取脱臭馏出物中V_E及V_E回添于大豆油中的研究

以大豆油脱臭馏出物为原料,先对其进行酶法甲酯化,再将甲酯化产物进行超临界CO_2萃取得到维生素E(V_E)。以单因素试验为基础,通过响应面优化确定萃取工艺的最佳条件为CO_2流量2.0 m L/min、萃取温度36℃、萃取压力14 MPa、萃取时间4 h,在此条件下萃取率为96.2%,所得V_E的纯度高达91.3%。通过抗氧化试验确定V_E回添到一级大豆油中的最佳添加量为0.02%,相对于未添加V_E的大豆油,其抗氧化效果明显提高,此时大豆油中V_E含量为112.43 mg/100 g。     

分子蒸馏浓缩天然VE的研究

本文以大豆油脱臭馏出物经皂化-甲酯化后的产物为原料,以高效液相色谱定量分析手段,进行了分子蒸馏浓缩天然VE的研究.确定了系统压力为1Pa时,最佳的工艺条件为预热温度80℃,蒸馏温度170 ℃,进料速率为120mL/h,刮膜转速为200 r/min.在此工艺条件下,分子蒸馏后重相中天然VE的含量达到56.1%,而收率达到91.3%.结果表明,分子蒸馏技术可以起到浓缩天然VE的作用,是从大豆油脱臭馏出物皂化-甲酯化产物中提取精制天然VE的比较好的预处理方法.     

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