大豆植物甾醇提取工艺的研究

以甲酯化大豆油脱臭馏出物经离子交换吸附维生素 E 后得到富含甾醇的过柱液为原料.以甲醇为提取溶剂,采用冷却结晶的方法分离粗甾醇,然后以丙酮为溶剂对粗甾醇进行重结晶.通过单因素和正交试验确定最佳结晶工艺条件为:结晶时间18 h,结晶温度0 ℃,原料与甲醇比 1:2(m/V).在此条件下甾醇纯度为83.74%,再用丙酮重结晶得到甾醇产品纯度为92.87%,收率为60.14%.     

茶油脱臭馏出物中甾醇精制的研究

采用乙醇萃取VE,皂化法提取茶油脱臭馏出物中甾醇化合物,以正己烷为结晶溶剂对甾醇化合物进行重结晶。VE最佳萃取参数:液料比3:1,搅拌时间30min,萃取温度55℃,搅拌速度80r/min。甾醇最佳的提取工艺条件:碱料比1(KOH):5,醇料比15(乙醇):1,皂化时间3h,温度85℃;最佳结晶工艺条件:液料比3:1,溶剂正己烷,结晶温度-2℃,结晶时间24h,三次重结晶后精制甾醇的纯度可以达到89.3%。     

超声辅助分步结晶法制备高纯度豆甾醇的工艺研究

通过富集和精制两步法分离纯化豆甾醇,采用非极性溶剂结晶法富集植物甾醇中的豆甾醇,在此基础上利用超声辅助在极性溶剂中对豆甾醇进一步重结晶精制。采用单因素实验对豆甾醇富集和精制工艺条件进行优化。结果表明:优化的富集工艺条件为以环己酮为溶剂、料液比1∶3. 5、养晶温度25℃、养晶时间16 h,在此条件下重复结晶5次,豆甾醇纯度提高到94. 69%;优化的精制工艺条件为以丙酮为溶剂、超声时间3 min、超声功率90 W、料液比1∶70、养晶温度25℃、养晶时间3 h,在此条件下重结晶2次,最终将豆甾醇的纯度提高至99. 36%;经质谱、红外光谱和核磁等结构鉴定确认样品为豆甾醇。     

甾醇单体的分离精制研究

本文测定了甾醇单体在不同溶剂中的溶解度数据,在此基础上,利用菜油甾醇、豆甾醇和β-谷甾醇在环己酮中的溶解度随温度变化的差异,用重结晶法提纯β-谷甾醇,经过3次结晶操作,β-谷甾醇的纯度达到86.58%;利用菜油甾醇、豆甾醇在正戊醇和环己酮中溶解度的差异,经过5次重结晶,结晶产品中豆甾醇的纯度分别达到96.1%和93.9%.     

结晶纯化脱臭馏出物中植物甾醇及其抗氧化作用研究

以菜籽油脱臭馏出物甲酯化所得的植物甾醇粗品为研究对象,考察了冷却结晶植物甾醇的工艺条件。采用紫外光谱、红外光谱、薄层层析、高压液相色谱及熔点法测定并验证了植物甾醇的结构,并对其抗氧化作用进行了初步研究。研究结果表明:以丙酮为结晶溶剂,料液比1∶10,结晶温度-5℃,养晶时间3h,甾醇纯度在95%以上,结晶得率在85%以上。将其添加于色拉油中,显示了较好的抗氧化作用。     

生物柴油生产废渣中植物甾醇的提取研究

以酶法生产生物柴油的废渣为原料,通过预处理、深度皂化、溶剂提取可得到天然植物甾醇。研究结果表明,1 mol/L KOH乙醇溶液体积与原料质量比为10∶1,皂化时间为5 h,皂化温度为80℃,正己烷体积与原料质量比为40∶1的条件下,粗植物甾醇的提取率和纯度分别为95.0%和50.1%。粗甾醇经无水乙醇重结晶2次后,其纯度可达90.13%。     

溶剂结晶过程对豆甾醇分离精制的影响

以95％混合植物甾醇为原料,研究了溶剂结晶过程中初始温度、降温速率、养晶时间、重结晶次数对豆甾醇含量和收率的影响.结果表明:在混合植物甾醇与溶剂比为1∶3,结晶终点温度为20℃,结晶初始温度为60℃,降温速率为3℃/h、养晶8h的条件下,经过6次结晶豆甾醇的含量达到95％以上,收率40％左右.在实际生产中可以在严格控制结晶过程的前提下,根据豆甾醇的不同规格要求调整适当的重结晶次数.     

从雄烯二酮发酵废液中分离甾醇和油脂的工艺研究

以雄烯二酮发酵废液为原料,采用有机溶剂萃取法和重结晶的方法对原料进行处理,分离获得甾醇和雄烯二酮产品。通过单因素实验考察不同溶剂、不同配比、不同温度等因素对分离影响。研究结果显示:以乙酸乙酯为溶剂,按料液比(1:3)萃取温度50℃、萃取两次、结晶温度为0℃、结晶时间为6 h、结晶二次得到甾醇提取率为46%,纯度达到80%以上;按料液比1:3加入甲醇溶解浓缩物,浓缩到体积的一半后,冷却结晶18 h,经离心得到雄烯二酮粗品。上清液再次浓缩,回收溶剂和副产品大豆油。该研究结果实现了雄烯二酮发酵废液的变废为宝及资源化综合利用。     

利用GC-MS检测和鉴定沙棘籽油甾醇

以沙棘籽油为样品,采用皂化法提取样品中的甾醇并对工艺进行优化,利用气相色谱-质谱联用(GC-MS)检测和鉴定样品中的甾醇。结果表明,最佳皂化条件为溶剂配比12.5:1、料液比1:15、温度95℃、时间1.5 h,提取率为3.5%。溶剂重结晶法对粗提甾醇进行精制,料液比1:10、溶解温度50℃、养晶温度4℃、养晶时间2 h、重结晶2次,精制甾醇纯度为84.5%。经GC-MS检测鉴定,样品中甾醇种类有菜油甾醇、δ7-燕麦甾烯醇、β-谷甾醇、δ5-燕麦甾烯醇4种,含量分别为2.2g/100 g、14.4 g/100 g、42.2 g/100 g、2.85 g/100 g,占总甾醇含量的61.65%。     

从葵花籽油脱臭馏出物中提取植物甾醇的研究

植物甾醇通常采用结晶方法从植物油脱臭馏出物(DD油)中提取.采用与乙醇酯化反应的产物(EDD)为原料,正己烷作为溶剂(S),S/EDD比率(W/W)为3～5时,研究了主要过程参数(溶剂、助溶剂、结晶温度和结晶时间)对植物甾醇提取率和纯度的影响.研究表明,溶剂和助溶剂的组成是最重要的过程参数,对甾醇的提取率和纯度影响很大,对它们的过滤性和水洗性也有影响.饱和水的己烷溶液具有好的结晶性,而且加入少量和适宜的乙醇能够加强水作为单一助溶剂的有益影响,通过使用S/EDD混合物(S/EDD=4)一次结晶,甾醇的提取率高达84%(纯度36%).     

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.     

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.     

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.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.