超滤法浓缩菜籽蛋白提取液的工艺研究

以双低菜籽粕为原料,采用超声波辅助萃取,得到菜籽蛋白提取液。对提取液进行超滤浓缩,探讨了操作压力、温度、pH、流速等参数对膜通量的影响。以膜通量为评价指标,通过正交实验,对操作压力、温度和pH三个因素进行了优化。结果表明,菜籽蛋白提取液最佳超滤工艺条件为：操作压力0.1MPa,温度40℃,pH9,流速2m/s。采用超滤,可得到毒素含量低,纯度在90%以上的菜籽蛋白产品。     

超滤技术处理酪蛋白酶解液的研究

采用超滤技术对酪蛋白酶解液进行浓缩分离，分析超滤过程中操作压力、料液pH、料液浓度等因素对膜透过速率的影响。结果表明．控制操作压力在0．35MPa，料液pH在7．0料液浓度为3％时，膜污染程度最轻，膜透过速率高。     

低聚木糖的超滤纯化生产工艺优化

以纯化分离秸秆酶解液中低聚木糖为目的,以蛋白、木质素去除率和低聚木糖的透过率为评价指标,采用工业化超滤膜分离装置,考察料液浓度、操作压力、温度、pH值对超滤除杂的影响。单因素实验确定初步的工艺条件后,Box-Behnken模型优化得最佳超滤纯化工艺条件为:料液浓度2.24°Bx,操作压力0.18 MPa,温度25℃,pH 7.0。在此条件下,低聚木糖的透过率为92.1%,蛋白去除率67.9%,木质素去除率67.8%,透过液澄清透亮。响应面法分析各因素对超滤提纯效果的影响,其强弱性依次为:料液浓度、pH值、操作压力、操作温度。     

酵母抽提物提取海藻糖超滤特性研究

采用聚醚砜超滤膜对酵母味素溶液进行超滤试验，并对超滤特性及影响特性的操作因素进行研究，结果表明：在整个超滤过程，通量衰减变化很大，蛋白质主体浓度的对数和渗透通量呈线性关系；随料液浓度增加，膜通量下降，蛋白截留率和海藻糖透过率增加；料液pH和操作压力均影响通量、蛋白截留率和海藻糖透过率。经提取后的海藻糖浓度为25．7％，整个过程海藻糖总提取率达89．8％。     

菜籽饼粕中分离蛋白的制备

在传统的碱提酸沉工艺基础上结合超滤制备菜籽分离蛋白。通过正交试验结果分析得到菜籽分离蛋白碱提酸沉条件为:在pH13,温度40℃,料液比(g/ml)分别为1:10、1:8和1:6下提取3次,每次40min;调pH4.5沉淀。上清液超滤工艺条件:40℃,流速2m/s,压力0.1MPa。喷雾干燥后产品的粗蛋白含量为70.5%,蛋白得率为54.7%。     

酵母抽提物超滤制备海藻糖工艺条件的优化

利用响应面分析法对影响酵母抽提液中总氮截留率和海藻糖透过率的主要因素进行分析,优化超滤工艺,得到最佳超滤条件:料液质量浓度10 g／dL,料液温度42℃,操作压力0.31MPa,在最佳超滤条件下得到酵母抽提物蛋白质截留率96.5%,海藻糖透过率94.8%,所得RSA图可直观地反映各因素与蛋白氮截留率和海藻糖透过率的关系.     

玉米胚芽蛋白酶解物的超滤工艺研究

采用超滤法探索了玉米胚芽蛋白酶解物中初步分离小肽的生产工艺,研究了料液浓度、操作压力、温度、时间对膜通量的影响,并利用高效凝胶过滤色谱(HPSEC)比较了超滤前后酶解物的分子量分布。结果表明:最佳操作条件为料液浓度15mg/mL、操作压力0.5MPa、温度25℃、超滤时间150min,超滤能够有效地将粗酶解液中未被水解的蛋白和高分子量的多肽去除。     

酪蛋白糖巨肽超滤分离的工艺优化研究

目的:研究超滤分离酪蛋白糖巨肽的最优工艺参数,以达到最佳超滤通量性能。方法:采用超滤方法分离乳清浓缩蛋白(WPC80)中的酪蛋白糖巨肽,研究料液pH值、操作压力和温度等对膜渗透通量的影响。利用SDS-PAGE凝胶电泳技术分析超滤截留液的相对分子量分布。结果:实验表明溶液pH7.0、操作压力0.3MPa、温度45℃时膜渗透通量最高,超滤酪蛋白糖巨肽的截留率达到97.54%,产物纯度达到92.45%,经SDS-PAGE凝胶电泳测定,酪蛋白糖巨肽的平均分子量68.86%为30.47ku,31.14%为19.22ku。结论:超滤技术是将酪蛋白糖巨肽与其他乳清蛋白分离的有效方法。     

盐提与膜分离偶联制备双低油菜籽蛋白

以双低油菜籽饼粕为原料,采用盐提与膜分离偶联工艺制备菜籽蛋白,结果表明,盐提温度及浓度是影响盐提工艺重要因素,盐提最佳条件为:4.0%NaCl,50℃,90min,料液比(w/v)1:20,在最佳艺条件下,菜籽蛋白提取率达67.9%;超滤膜分离适宜工艺条件为:超滤膜MWCO100000,物料初始蛋白质浓度为4.0%,料液pH10.0,超滤操作温度为50℃,进出口压差0.12MPa,在此条件下,菜籽蛋白截留率>90%,产品蛋白质纯度为85.11%。采用盐提与超滤偶联处理菜籽饼粕,可得到高纯度菜籽蛋白,同时大幅度降低产品抗营养因子。     

正交试验优化银条多糖超滤浓缩工艺

以膜通量为指标,首先探讨操作压力、超滤温度和料液pH值3个工艺参数对超滤浓缩银条多糖的影响,在此基础上通过正交试验确定超滤浓缩的最佳工艺参数,最后通过测定清洗前后膜的水通量变化确定最佳的超滤膜清洗方法。结果表明超滤浓缩效果优于常规浓缩的效果,超滤浓缩银条多糖的最佳工艺参数为操作压力0.35MPa、操作温度30℃、料液pH6.5;最佳膜清洗方法为用40℃、pH8.5的NaOH溶液清洗0.5h,此时清洗前后纯水的膜通量相差9.00L/(m2.h)。     

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