超临界CO2萃取核桃油的研究

研究了影响核桃油超临界CO2流体萃取的因素,在试验条件下,其影响因素次序为:夹带剂、萃取压力、CO2体积,萃取温度影响不大.优化了超临界CO2流体萃取核桃油的工艺条件:夹带剂无水乙醇,用量为投料量的质量分数的10%;萃取压力30 MPa,萃取温度35℃,萃取时间3.5 h,CO2流量15～20kg/h.用气相色谱法分析了超临界CO2流体萃取核桃油的脂肪酸酸组成和含量,其不饱和脂肪酸含量较高.     

超临界CO2萃取竹叶中总黄酮的研究

采用超临界CO2萃取技术,在CO2流量为25L／h的条件下,对影响竹叶中总黄酮提取率的4个因素（温度、时间、压力和夹带剂用量）进行了研究。运用正交试验得出了最佳的萃取工艺条件为温度为40℃,时间为3h,压力为30MPa,夹带剂用量为4．5mL／g。     

超临界CO2萃取芦笋中总黄酮的工艺研究

采用超临界CO2萃取技术对芦笋中的黄酮类化合物进行了萃取研究，运用L9（3^4）正交表系统研究了萃取压力，萃取温度，萃取时间以及夹带剂用量对萃取率的影响。确定了超临界CO2萃取芦笋总黄酮的最佳工艺条件为：温度为70℃、时间为2h、压力为30MPa、夹带剂（75％乙醇）用量为2．0mL／g。此条件下得到总黄酮比率为1．35％，其黄酮得率是常规溶剂乙醇提取法总黄酮得率的2．7倍。     

超临界CO2萃取车前草中熊果酸的工艺研究

目的:研究超临界CO2萃取车前草中熊果酸的工艺条件.方法:探讨萃取压力、萃取温度、萃取时间、夹带剂类型及用量对熊果酸收率的影响,确定了超临界CO2萃取车前草中熊果酸的适宜条件.结果:超临界萃取最优条件为萃取压力35 MPa,萃取温度为40℃,选择无水乙醇为夹带剂,夹带剂质量分数为20%,萃取时间2 h,CO2流量为20 L/h,产品的出膏率为3.58%,萃取物中熊果酸的含量为6.93%.结论:该法与传统方法相比,具有操作简便快速,溶剂用量少,有效成分提取率高等优点.     

超临界CO2提纯大豆磷脂的研究

以粉末大豆磷脂为原料,无水乙醇为夹带剂,用超临界CO2提取磷脂酰胆碱（PC）,通过单因素实验,考察了萃取压力、温度、时间对PC提取效果的影响,并在此基础上,选择3因素3水平进行正交实验,得到超临界CO2／乙醇提取PC的最优条件为：萃取压力20MPa,温度50℃,时间6h。在此条件下,所得产物经HPLC法检测PC纯度为71．75％。     

藜蒿黄酮超临界CO2(SFE-CO2)萃取条件的研究

采用超临界CO2萃取藜蒿中黄酮类物质。考虑萃取温度，压力，夹带剂用量等因素在不同水平下对藜蒿黄酮提取率的影响，并对结果进行方差分析和显著性检验。实验表明：以1.5ml/g无水乙醇为夹带剂在35℃，30MPa条件下萃取为最佳条件。     

超临界CO2萃取大蒜油的工艺研究

本文研究了影响超临界流体萃取（SFE）技术对大蒜油提取的相关因素，包括萃取压力、萃取温度、萃取时间、夹带剂用量等。通过正交试验，确定了超临界CO2萃取大蒜油的适宜工艺参数组合：以15％（V／W）无水乙醇为夹带剂，萃取压力为25MPa，萃取温度为40℃，萃取时间为240rain，在上述提取条件下，SFE提取的大蒜油得率达到0．446％。结果表明：超临界流体萃取的大蒜油呈淡黄褐色，半透明状，略有流动性，呈新鲜大蒜风味。     

超临界CO_2流体萃取法提取姜黄素的研究

姜黄素是国内外食品行业允许使用的重要天然色素之一,具有很大的市场潜力。本实验采用超临界CO2流体萃取法提取姜黄中有效成分姜黄素,通过正交实验探讨了原料粒度、萃取压力、萃取温度、萃取时间、CO2流量及夹带剂(95%乙醇)用量等对姜黄素提取效果的影响。结果表明:夹带剂用量和萃取压力是最重要的影响因素,最佳提取条件为原料粒度1.0mm,萃取压力为35MPa,萃取温度40℃,萃取时间3h,CO2流量30L/h,夹带剂用量1mL/g;在最佳萃取条件下,姜黄素含量为14.317mg/g。     

响应面分析法优化亚麻籽油超临界CO2萃取工艺

以亚麻籽为原料,利用夹带剂、超临界CO_2萃取装置提取亚麻籽油,确定最佳夹带剂以及夹带剂用量,考察萃取压力、萃取温度、萃取时间和CO_2流量4个单因素,根据Box-Behnken试验设计原理,以亚麻籽提油率为响应值,采用四因素三水平的响应面分析法,在分析各个因素的显著性和交互作用后,得到最佳萃取工艺条件:以无水乙醇为夹带剂,料液比(物料与夹带剂质量体积比)1∶0.8,萃取温度46℃,萃取压力35 MPa,萃取时间50 min,CO_2流量5.5 L/h。在最佳萃取工艺条件下进行5次平行验证试验,得到亚麻籽提油率为37.98%。     

超临界CO_2萃取玫瑰精油的工艺优化

为提高超临界CO2萃取干玫瑰花中玫瑰精油的产品得率,依次考察了乙醇夹带剂浓度、萃取压力、温度、夹带剂流量及萃取时间等因素的影响,通过正交实验,进行了产品得率的工艺优化。结果发现:无水乙醇较乙醇水溶液更适于作萃取的夹带剂;此外,随着萃取压力、温度、夹带剂流量及萃取时间的增加,所得精油产品中主香组分2-苯乙醇的得率均呈现先增后减的变化趋势;其中,萃取压力、夹带剂流量和萃取温度三因素,对得率指标的影响依次减弱。所得优化的工艺组合为萃取压力23MPa、温度40℃、夹带剂流量0.06m L/min、萃取时间1.5h,对应2-苯乙醇的得率可达0.795‰。     

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.     

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.     

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.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.