脂肪酶Bakezyme LFP水解大豆粉末磷脂研究

以酸值为指标,通过单因素实验和正交实验确定了脂肪酶Bakezyme LFP在水相中水解大豆粉末磷脂的最佳工艺条件为:反应温度为50℃,反应时间为8h,p H为5.0,加酶量为8%,底物质量浓度为25mg/m L。在该工艺条件下,大豆磷脂水解产物酸值为65.2mg KOH/g。利用气相色谱-质谱联用仪分析了水解前后大豆磷脂的脂肪酸组成,结果表明水解后饱和脂肪酸含量明显下降,不饱和脂肪酸含量明显增加,说明脂肪酶Bakezyme LFP主要水解大豆磷脂1位上脂肪酸,具有磷脂酶A1的特性。利用高效液相色谱分析水解前后大豆磷脂的磷脂酰乙醇胺(PE)和磷脂酰胆碱(PC)含量,结果表明大豆磷脂中PE、PC发生水解,生成溶血磷脂。     

溶剂法精制磷脂酰胆碱的研究

为了提高磷脂产品中磷脂酰胆碱(PC)的含量,研究了以浓缩大豆磷脂为原料,采用丙酮和乙醇作溶剂,制备高含量磷脂酰胆碱.用丙酮脱油时,在料溶比为15:200、提取时间15 min、提取温度40℃的最佳脱油工艺条件下,得到丙酮不溶物含量为97.6%的中间产物--粉末磷脂.用乙醇提取富集其中的磷脂酰胆碱,通过单因子试验,研究了粉末磷脂与溶剂的比例、乙醇浓度、提取温度、时间和次数对PC含量和提取率的影响.试验结果表明,在乙醇浓度95%,固液比1:20,提取时间30 min,温度35℃,抽提次数2次的条件下,PC含量和提取率均较优.在最佳试验条件下,PC含量可提高到45.1%,提取率为62.0%.     

HPLC-ELSD法测定大豆磷脂中磷脂酰胆碱和溶血磷脂酰胆碱含量

该研究探讨采用HPLC–ELSD(蒸发光散射检测器)法测定大豆磷脂中磷脂酰胆碱和溶血磷脂酰胆碱含量。结果表明,选用硅胶色谱柱(150 mm×4.6 mm,5μm),磷脂酰胆碱(PC)和溶血磷脂酰胆碱(LPC)分别在0.5 mg/mL~8.0 mg/mL和0.4 mg/mL~6.0 mg/mL范围呈良好线性关系;PC和LPC平均回收率为99.42%和99.83%,相对标准偏差(RSD)分别为1.44%和1.21%。该法对大豆磷脂PC和LPC分析均具有良好精密度和重复性。     

大豆磷脂作乳化剂制备柴油-乙醇乳化燃料

以大豆磷脂为乳化剂制备柴油-乙醇乳化燃料。研究了磷脂中磷脂酰胆碱(PC)含量、磷脂加入量、醇油比、乳化温度、搅拌速度、搅拌时间等因素对乳化液稳定性的影响。确定最佳乳化条件为:柴油-乙醇体积比4∶1,乳化剂采用PC含量10%的大豆磷脂,磷脂加入量1%,乳化温度30℃,搅拌速度3 000 r/m in,搅拌时间15 m in。确定了乳化剂的最佳HLB值为3.8,并以此为依据,将磷脂与化学合成乳化剂的乳化能力进行了比较。发现磷脂的乳化能力高于单一乳化剂,而小于复合乳化剂。     

不同形态大豆磷脂产品中溶血磷脂酰胆碱含量研究

采用HPLC–ELSD法测定不同形态大豆磷脂产品中溶血磷脂酰胆碱(LPC)的含量,并通过对原料、工艺、储存期等因素的研究来确定溶血磷脂酰胆碱含量的变化规律。浓缩磷脂产品中LPC含量约为0.80%,大豆粉末磷脂中LPC含量为1.35%,大豆磷脂一次醇溶产品中LPC含量为2.87%,大豆磷脂二次醇溶产品中LPC含量为12.88%。在–20℃、避光储存条件下,各样品一年储存期内LPC含量的变化不大。     

国际粮油近讯

<正> 大豆磷脂系精炼大豆油脱胶时副产品,若以2％含量计,日本现有油厂约有1.34万吨生产能力,但实际上全日本仅有6～7家公司生产大豆磷脂、每年回收磷脂约1万吨左右。大豆磷脂制品主要以磷脂酰胆碱(PC)含量为分,包括从15％含量粗制糊状品至98％以上高纯度粉末状精制品。日本工业生产大多为粗制磷脂,主要作食品乳化剂之用,日本年需求量予计约7000～8000吨,其余绝大部份直接作饲料添加剂。大豆磷脂系由磷脂酰胆碱(PC),磷脂酰乙醇胺(PE),磷脂酰肌醇(PI)和磷脂酸(PA)为主成份组成磷脂质混合物。其结构含有疏水性脂肪酸基和亲水性磷酸酯基,PI和PA具有阴离子,而PC与PE     

超临界流体分离大豆磷脂酰胆碱

研究了超临界流体CO2 /乙醇分离大豆磷脂酰胆碱的影响因素。结果表明 :在温度 4 0℃- 6 0℃ ,压力在 15MPa - 2 5MPa ,乙醇浓度在 2 % - 2 0 %之间 ,较低的温度 ,较高的压力和较高的乙醇浓度有利磷脂酰胆碱含量的提高。在温度 4 0℃、压力 2 5MPa、乙醇浓度 15 % (v/v)下 ,磷脂酰胆碱含量可达 89% (TLC扫描法 )     

乙醇低温提取纯化磷脂酰胆碱研究

该文研究在低温条件下,用乙醇作为溶剂,从大豆磷脂粉中精制磷脂酰胆碱工艺。通过单因素实验考察了提取温度、提取时间、乙醇浓度和料液比等因素在不同水平下对磷脂酰胆碱含量和得率影响。在综合考虑纯度和得率基础上,选取以乙醇(95%)为溶剂,提取温度–10℃、提取时间20 h、液料比为8∶1条件下进行中试。中试产品磷脂酰胆碱的纯度为71.74%,得率为13.48%。     

乙醇低温提取纯化磷脂酰胆碱研究

该文研究在低温条件下,用乙醇作为溶剂,从大豆磷脂粉中精制磷脂酰胆碱工艺。通过单因素实验考察了提取温度、提取时间、乙醇浓度和料液比等因素在不同水平下对磷脂酰胆碱含量和得率影响。在综合考虑纯度和得率基础上,选取以乙醇(95%)为溶剂,提取温度–10℃、提取时间20 h、液料比为8∶1条件下进行中试。中试产品磷脂酰胆碱的纯度为71.74%,得率为13.48%。     

大豆磷脂软胶囊贮藏过程中品质变化研究

以大豆磷脂软胶囊为研究对象,对其在贮藏过程中的磷脂酰胆碱含量、酸值、水分含量、稀释剂大豆油的甘油酯组成进行研究,探究其品质变化规律及原因。结果表明:随着贮藏时间的延长,大豆磷脂软胶囊中磷脂酰胆碱含量降低,酸值升高,溶血磷脂的含量升高。囊壳内水分在大豆磷脂软胶囊贮藏过程中向内容物迁移,促进磷脂酰胆碱水解,产生溶血磷脂。稀释剂大豆油也发生水解,释放出脂肪酸,这两部分水解造成酸值升高。     

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