4种主要麻类植物种子含油量及油中脂肪酸组成分析

为探明苎麻、红麻、大麻和亚麻4种主要麻类植物种子油开发利用价值,采用索氏提取法和气相色谱法对其种子含油量和种子油脂肪酸组成及含量进行了比较研究。结果表明:4种麻类植物种子含油量差异较大,其含油量大小顺序为亚麻大麻红麻苎麻,均值分别为36.54%、33.43%、23.44%和18.77%;4种麻类植物种子油主要由棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸5种脂肪酸组成,其含量占总脂肪酸的97.40%以上,其中不饱和脂肪酸含量均值变幅为74.87%~92.43%,以苎麻籽油最高,亚麻籽油和大麻籽油稍次,红麻籽油最低。4种麻类植物种子油与其他植物油脂肪酸组成相比,具有各自优势特征,红麻籽油油酸含量最高(30.09%),明显优于其他3种麻类植物种子油及葵花籽油和大豆油;苎麻籽油含有丰富亚油酸(81.38%),远超过葵花籽油、大豆油、菜籽油、橄榄油和其他3种麻类植物种子油;亚麻籽油和大麻籽油亚麻酸含量具有明显优势,分别为51.27%和18.47%,远高于红麻籽油、苎麻籽油和其他4种植物油。综合分析可见,4种主要麻类植物种子对于特种保健食用油的开发利用具有重要价值和极具发展潜力。     

苎麻属野生植物种子油中脂肪酸组成及其粕氨基酸分析

为探明苎麻属野生植物种子油的开发利用价值,采用索氏抽提法、气相色谱法和氨基酸分析仪对其种子含油量、油中脂肪酸组成及其粕氨基酸组成进行测定分析。结果表明:苎麻属野生植物种子含油量较高,最高达28.46%,平均值达21.63%,显著高于栽培种苎麻;油中脂肪酸主要由5种脂肪酸组成,平均含量顺序为亚油酸(80.6%)油酸(10.6%)棕榈酸(5.8%)硬脂酸(2.1%)亚麻酸(0.3%);其不饱和脂肪酸含量达90%以上,明显优于红麻籽油、棉籽油、红花籽油、橄榄油、大豆油和菜籽油;其含油量与棕榈酸、硬脂酸和油酸呈负相关,与亚油酸、亚麻酸呈正相关;亚油酸与棕榈酸、硬脂酸呈负相关,其中与硬脂酸达显著水平;苎麻属野生植物种子粕共有17种氨基酸,其中含7种必需氨基酸,占总氨基酸的39.24%~41.24%。综合分析可见,苎麻属野生植物种子中存在丰富优异种质,对于苎麻品质育种和营养保健油开发具有重要价值。     

发育紫苏种子营养累积与脂肪酸组分变化

对6个不同品种紫苏种子发育过程中粗脂肪、蛋白质含量进行了测定,并通过气相色谱对2个品种的脂肪酸组分变化规律进行了检测分析。结果表明,蛋白质在结实后10~20 d内即可完成基本累积过程,而粗脂肪累积需要20~30 d才能完成。6个品种中含粗脂肪32.6%~44.4%,含蛋白质21.4%~24.9%,ZY-14和ZY-12粗脂肪和蛋白质含量均较高,是适合油用和饲料加工的优质品种。紫苏脂肪酸主要由棕榈酸、硬脂酸、油酸、亚油酸和α-亚麻酸5种成分组成,不饱和脂肪酸占总脂肪酸的91.6%~95.0%,其中α-亚麻酸占总不饱和脂肪酸的66.8%~73.3%。种子发育过程中,棕榈酸、硬脂酸和油酸含量相对稳定,亚油酸含量随种子发育逐渐降低,而α-亚麻酸含量不断增加直至成熟。     

甘肃亚麻籽油与小品种油脂肪酸组成的比较分析

对甘肃产亚麻籽油与其它6种小品种食用油脂肪酸的组成成分进行测定,结果表明,亚麻籽油中α-亚麻酸含量最高(平均值为54.1%),其次是油酸(平均值为24.25%);紫苏油、牡丹籽油、松子油不饱和脂肪酸含量高,其中松子油的单不饱和脂肪酸含量最高,紫苏油的多不饱和脂肪酸含量最高,南瓜籽油二十二碳六烯酸(DHA)平均含量0.106%,御米油二十碳五烯酸(EPA)平均含量0.242%。硬脂酸、棕榈酸、油酸、亚油酸和α-亚麻酸是构成甘肃地产亚麻籽油的特征脂肪酸。甘肃产亚麻籽油的ω-3系脂肪酸与ω-6系多不饱和脂肪酸的比是1.6∶0.4,仅次于紫苏油,是健康饮食的高品质油脂。     

美国引进向日葵种子含油量和脂肪酸组成比较分析

以天津检验检疫局引进的24种美国向日葵种子为原料,其中食用型和油用型种子各12种,测定了24种向日葵种子的含油量,并用气相色谱法测定了向日葵种子油脂肪酸组成及相对含量。结果表明:24种向日葵种子含油量介于33.26%~47.24%之间;向日葵种子油脂肪酸组成为棕榈酸、硬脂酸、油酸和亚油酸,油酸和亚油酸的相对含量较高,油酸相对含量介于16.07%~91.30%之间,亚油酸相对含量介于2.33%~71.45%之间,不饱和脂肪酸相对含量介于87.43%~93.63%之间;分析发现,油用型向日葵种子油的油酸含量相对较高,食用型向日葵种子油的亚油酸含量相对较高。     

食用植物油中4种不饱和脂肪酸在sn-2位含量分析

植物油的sn-2位不饱和脂肪酸比sn-1(3)位的不饱和脂肪酸更易被人体吸收,因此对食用植物油中sn-2位脂肪酸含量进行分析有实际意义。实验采用气相色谱法对油酸(C18∶1n9c)、亚油酸(C18∶2n6c)、γ-亚麻酸(C18∶3n6)、α-亚麻酸(C18∶3n3)等4种不饱和脂肪酸在10种共计12个食用植物油样品中总脂肪酸和sn-2位的具体含量进行检测。总脂肪酸中油酸(C18∶1n9c)含量最高的为花生油,为40.06 g/100g,而sn-2位油酸含量最高的是茶籽油,为1.11 g/100g。大豆油在总脂肪酸中含亚油酸(C18∶2n6c)最多,为68.49 g/100g,但在sn-2位中含亚油酸最多的是核桃油,为0.97 g/100g。sn-2位γ-亚麻酸(C18∶3n6)、α-亚麻酸(C18∶3n3)含量最高的则是亚麻籽油,分别为0.09 g/100g和0.32 g/100g。通过分析常见植物油的4种不饱和脂肪酸总量及在sn-2位上的含量,可为食用植物油的营养价值分析、相关的食品和保健品等产品研发提供科学的数据支持。     

新疆野蔷薇种子油的脂肪酸组成分析

采用超声辅助提取法提取野蔷薇种子油,以气相色谱-质谱联用技术对油脂进行脂肪酸组成分析.结果表明:野蔷薇种子油中的主要脂肪酸为棕榈酸、油酸、亚油酸、亚麻酸,其中不饱和脂肪酸占总量的92.41%;主要成分棕榈酸占5.88%,油酸占12.39%,亚油酸占56.52%,亚麻酸占23.50% .     

狼紫草籽油中脂肪酸组成的研究

采用毛细管气相色谱法测定了狼紫草籽油中的脂肪酸组成及相对含量。鉴定了１５种脂肪酸，占脂肪酸总量的９９．３％。样品所含主要脂肪酸为棕榈酸、油酸、亚油酸、α—亚麻酸和γ—亚麻酸。不饱和脂肪酸为９０．６４％，其中α—亚麻酸２６．８８％，γ—亚麻酸６．７０％。     

牡丹种皮、种子及4种干果油脂的脂肪酸组成分析

目的明确牡丹种皮油的脂肪酸组成及相对含量,并与牡丹籽油和4种常见干果(核桃、巴旦木、杏仁、开心果)的脂肪酸组成进行比较,为牡丹种皮油的开发利用提供科学依据。方法采用索氏抽提法对4种干果中的脂肪进行提取,以硫酸-甲醇法对6种油脂样品甲酯化,采用GC-MS检测结合峰面积归一化法测定脂肪酸的组成及相对含量。结果牡丹种皮油与牡丹籽油中均含有棕榈酸、棕榈油酸、油酸、亚油酸、亚麻酸5种脂肪酸,其不饱和脂肪酸比例均超过90%,尤其是亚麻酸的含量分别高达51.1%和44.7%;而核桃中含有棕榈酸、油酸、亚油酸、亚麻酸4种脂肪酸,亚油酸是其主要成分;巴旦木、杏仁、开心果中主要含有棕榈酸、油酸、亚油酸3种脂肪酸,以单不饱和脂肪酸油酸含量最高。结论牡丹种皮油中含有大量多不饱和脂肪酸,其中亚麻酸的含量尤其突出,较牡丹籽油含量更高,是一种优质的保健食用油。     

10种小宗植物油的脂肪酸组成及氧化稳定性

考察山茶籽油、乳木果油、亚麻籽油、牡丹籽油、核桃油、葡萄籽油、玫瑰果油、紫苏籽油、石榴籽油和甜杏仁油10种植物油的脂肪酸组成、酸价、过氧化值（POV）、硫代巴比妥酸（TBA）值和油稳定性指数（OSI）。结果显示：10种植物油中,除乳木果油不饱和脂肪酸含量偏低,为50.41%（质量分数）,其余植物油不饱和脂肪酸含量均较高（84.34%~92.47%,质量分数）。亚麻籽油和牡丹籽油的主要脂肪酸为α-亚麻酸,山茶籽油和乳木果油主要脂肪酸含量为油酸＞亚油酸＞α-亚麻酸,剩余6种植物油则为亚油酸＞油酸＞α-亚麻酸。根据酸价,山茶籽油、玫瑰果油与紫苏籽油品质最好,亚麻籽油则相反,新鲜度最低。综合POV和TBA值两个指标,亚麻籽油主要处于深度氧化阶段,核桃油虽已深度氧化但仍主要为初级氧化产物,乳木果油与葡萄籽油更易发生深度氧化,剩余植物油氧化程度不高。乳木果油的OSI最高,核桃油最低,且10种植物油的OSI与多不饱和脂肪酸质量分数、不饱和脂肪酸质量分数呈显著负相关,与饱和脂肪酸质量分数、饱和脂肪酸/不饱和脂肪酸比例呈显著正相关。研究结果为进一步开发我国植物油产品提供依据。     

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.