巴旦杏仁油的超临界CO_2萃取工艺及其成分研究

研究巴旦杏仁油的超临界CO_2萃取工艺,通过单因素试验和正交试验设计探讨了萃取压力、温度、CO_2流量和萃取时间对巴旦杏仁油超临界CO_2萃取得率的影响。结果表明萃取压力35 MPa、萃取温度40℃、二氧化碳流量6 L/min、萃取时间4 h为最优条件,在此条件下巴旦杏仁油萃取得率达到43.10%;采用气相色谱-质谱(GC-MS)联用技术对巴旦杏仁油脂肪酸组成进行分析,结果表明巴旦杏仁油不饱和脂肪酸质量分数高达92.20%,以油酸(78.448%)、亚油酸(13.723%)为主,饱和脂肪酸以棕榈酸(6.018%)为主。     

超临界CO2流体萃取大扁杏杏仁油工艺研究

利用超临界CO2 流体萃取技术从大扁杏杏仁中提取杏仁油。确定了超临界CO2 流体萃取杏仁油的最佳工艺参数为：萃取压力30MPa,萃取温度50℃,粒径40 目,萃取时间2.5h。此条件下杏仁油得率为49.85%。各因素对大扁杏杏仁油得率的影响次序为：萃取压力＞萃取时间＞萃取温度＞粒径。     

超临界CO2萃取杭白菊挥发油的工艺研究

采用超临界CO2 技术萃取杭白菊挥发油,以杭白菊挥发油得率为指标,采用正交试验考察萃取温度、萃取压力、CO2 流量、萃取时间4 个因素对杭白菊挥发油的超临界CO2 流体萃取的影响。结果表明萃取压力20MPa、萃取温度55℃、CO2 流量10kg/h 的条件下萃取2h 为最佳工艺,杭白菊挥发油得率达5.92%。     

超临界CO2萃取甜瓜籽油工艺及其脂肪酸组成分析

采用超临界CO2萃取技术提取甜瓜籽油,在单因素实验的基础上,运用正交实验设计优化工艺条件。结果表明超临界CO2萃取甜瓜籽油的最佳工艺条件为:萃取压力30 MPa,萃取温度45℃,萃取时间5 h,CO2流量8 L/min,甜瓜籽粉碎粒度24目。在最佳条件下,甜瓜籽油得率为29.34%。利用GC-MS对甜瓜籽油脂肪酸组成进行分析,结果表明超临界CO2萃取的甜瓜籽油共鉴定出12种脂肪酸,其中饱和脂肪酸以棕榈酸(10.87%)、硬脂酸(5.57%)为主,不饱和脂肪酸以亚油酸(64.29%)、油酸(16.64%)为主。     

超临界CO2萃取灵芝孢子油工艺条件的响应面优化

对超临界CO2萃取灵芝孢子油的工艺条件进行响应曲面法优化探讨。结果表明:以灵芝孢子油得率为响应指标,拟合二次多项式回归曲线,分析得出萃取压力、萃取温度、萃取时间和CO2流量对得率有显著性影响,确定优化的萃取条件为:萃取压力29 MPa,萃取温度35℃,萃取时间3.5 h,CO2流量20 L/h。在优化条件下灵芝孢子油萃取得率可达26.13%。     

超临界CO2萃取肉桂精油的初步研究

文章研究了CO2流量、萃取压力、萃取时间和萃取温度四个因素对肉桂精油超临界CO2萃取的影响,以肉桂精油得率为指标,采用正交试验方法优选了萃取条件.结果表明:肉桂精油最佳萃取条件为,CO2流量为20 kg/h、萃取压力25 MPa、萃取时间2.5 h、萃取温度45℃,此条件下肉桂精油的得率为3.8%.     

超临界CO_2动静态萃取扁杏仁油的响应面优化

以张家口地产的"优一"扁杏仁为原料,利用超临界CO_2萃取法,在单因素试验研究的基础上,选择5个主要的影响因子萃取釜压力、萃取釜温度、CO_2流量、静态萃取时间和动态萃取时间,以杏仁油萃取率为响应值,采用Box-Behnken响应曲面法(Response surface methodology,RSM)对提取工艺进行了优化。结果表明,超临界CO2萃取扁杏仁油的最佳工艺条件为萃取釜压力70 MPa,萃取釜温度为50℃,CO2流量为7 L/min,静态萃取时间为80 min,动态萃取时间为72 min、粉碎粒径为30目,一次性加料量为30 g,分离釜温度为120℃,其得油率为49.12%。     

莴苣籽油的超临界CO_2萃取工艺及其脂肪酸组成分析

以莴苣籽为原料,利用超临界CO2对其进行萃取。通过单因素实验考察了萃取压力、萃取温度、萃取时间、CO2流量、一次性投料量、粉碎粒度对莴苣籽油得率的影响。在单因素实验的基础上,采用正交实验优化了超临界CO2萃取莴苣籽油的最佳工艺,并采用气相色谱-质谱(GC-MS)联用技术分析其脂肪酸组成。结果表明,超临界CO2萃取莴苣籽油的最佳工艺条件为:一次性投料量50 g,粉碎粒度24目,萃取压力30 MPa,萃取温度45℃,CO2流量6 L/min和萃取时间4 h。在最佳工艺条件下,莴苣籽油得率为17.92%。莴苣籽油脂肪酸组成主要为亚油酸(56.420%)、油酸(22.562%)、棕榈酸(7.795%),其中不饱和脂肪酸含量为86.682%。     

超临界CO2萃取黑胡椒精油的研究

研究了CO2流量、萃取压力、萃取时间和萃取温度四个因素对黑胡椒精油超临界CO2萃取的影响,以黑胡椒精油得率为指标,通过正交试验方法优选了萃取条件.结果表明:黑胡椒精油最佳萃取条件为:CO2流量22 kg/h、萃取压力34 MPa、萃取时间140 min、萃取温度38℃,此条件下黑胡椒精油的得率为7.02％.     

超临界CO2萃取紫苏叶挥发油的工艺优化

目的：采用超临界CO2流体萃取技术萃取紫苏叶挥发油,优化萃取工艺。方法：以紫苏叶挥发油得率为指标,通过单因素试验和正交试验考察萃取温度、萃取压力、CO2流量、萃取时间4个因素对紫苏叶挥发油的超临界CO2流体萃取的影响。结果：萃取压力20MPa、萃取温度35℃、CO2流量为10kg/h的条件下萃取150min为最佳工艺。结论：超临界CO2流体萃取技术萃取紫苏叶挥发油得率达3.2%。     

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.     

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.     

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.