一种家庭用营养均衡型配方食用油的加热及烹饪稳定性北大核心CSCD

通过模拟加热(180℃加热15、30 min)及家庭烹饪(炒青菜)过程,研究了一种富含不饱和脂肪酸、n-6/n-3脂肪酸比例适宜且有益脂质伴随物含量丰富的配方食用油的加热及烹饪稳定性。结果表明:配方食用油在加热或烹饪青菜时其酸值、过氧化值略有上升,但均远低于GB 2716—2018的规定;加热和炒菜过程中不会造成反式脂肪酸含量的增加,且苯并(a)芘含量远低于国标限量,说明在加热和炒菜过程中该配方食用油能够保持安全稳定;此外,配方食用油脂肪酸组成在加热或烹饪前后变化不大,n-6/n-3脂肪酸比例稳定,生育酚和总酚含量在加热和烹饪后下降幅度在35%以内,植物甾醇含量下降约12%。由此可知,配方食用油能够在常规家庭烹饪过程中保持稳定,是一种日常补充n-3多不饱和脂肪酸和有益脂质伴随物的有效途径。     

烹饪时间对鱼肉中脂肪酸的影响

目的 考察不同烹饪时间对鱼肉中脂肪酸营养价值的影响, 并对不同鱼类的适宜烹调时间进行评价。方法 采用清蒸的方式对秋刀鱼、石斑鱼、鲫鱼和罗非鱼进行烹调, 利用氯仿-甲醇提取法提取鱼肉脂肪酸, 通过气相色谱技术(gas chromatography, GC)对鱼肉中脂肪酸进行定性定量, 讨论烹饪时间对不同鱼肉中脂肪酸含量变化的影响。结果 随着烹饪时间的增加, 4种不同种类的鱼肉中不饱和脂肪酸的含量都呈现下降趋势, 当烹饪时间为0.5~1.0 h时, 不饱和脂肪酸二十碳五烯酸(eicosapentaenoic acid, EPA)、二十二碳六烯酸(docosahexaenoic acid, DHA)、油酸、亚油酸、亚麻酸含量下降速率最快并且产生有害脂肪酸(反式脂肪酸), ω-6/ω-3脂肪酸比值也呈现出上升趋势, 鱼肉脂肪酸营养价值降低。结论 在对鱼肉进行烹饪时, 应严格控制鱼肉烹饪时间在0.5 h左右, 才能有效的保证鱼肉中脂肪酸的营养价值。     

我国主要食用植物油中反式脂肪酸的研究

以GB/T 22110-2008为检测方法,对我国市场上销售的主要食用植物油(调和油、大豆油、花生油、芝麻油)中反式脂肪酸含量进行测定.结果显示:十八碳类反式脂肪酸有6种检出,同一油种具有相同种类的反式脂肪酸,各种类反式脂肪酸含量变化具有同步性,并呈显著性相关,各类反式脂肪酸在产生时具有相同的异构几率;当一种食用植物油的某类反式脂肪酸总含量接近或超过相应脂肪酸组成含量时,这份油样肯定不是单一品种的油样;反式脂肪酸主要来源于食用植物油的精炼过程,尤其是脱臭过程;我国存在因为反式脂肪酸摄入量过高而影响健康的情况,消费者、企业及政府部门应对食用植物油中反式脂肪酸的含量引起足够的重视.     

功能性调和菜籽油制备及脂肪酸组成分析

以菜籽油、亚麻籽油、青藏高原牦牛酥油为原料,分别按照牦牛酥油∶亚麻籽油∶菜籽油质量比为1∶2∶7（A）、1∶1∶8（B）、2∶1∶7（C）制备调和油,通过单因素试验和正交试验分别确定3种调和油中牦牛酥油溶解率的最佳工艺条件;利用气相色谱-质谱法（gas chromatography-mass spectrometry,GC-MS）分别对3种调和油及其沉淀进行脂肪酸组成分析。结果表明,3种调和油均无异味,酸值、过氧化值均符合国家食用油标准,油脂品质高、稳定性强、不易变质;所有调和油及其沉淀物质共检出脂肪酸44种,单一样品脂肪酸检出种类在39种～44种之间;共检出8种支链脂肪酸,其中,调和油C中支链脂肪酸含量最多,为2.92%;3种调和油中检出的主要脂肪酸为棕榈酸、亚麻酸、亚油酸、油酸,ω-6、ω-3脂肪酸含量的比值在1.29～1.80之间,从营养价值角度出发,调和油A中ω-6脂肪酸和ω-3脂肪酸比值较小,脂肪酸含量的比例更接近1∶1。     

不同时期母乳中脂肪酸水平的变化

目的:了解不同哺乳期母乳中各种脂肪酸水平的差异及其变化趋势,为母乳喂养及婴幼儿配方奶粉的配制提供科学依据。方法:收集2015年7月—2016年3月,在北京大学人民医院足月顺产的25~40岁产妇产后1~5d的初乳、6~10d的过渡乳和30d的成熟乳123份,采用气相色谱质谱联用法(GC-MS)检测母乳中的脂肪酸成分,分析母乳中各脂肪酸水平的差异及随时间的变化趋势。结果:随着泌乳时间的延长,C18∶0、C14∶1ω5、C18∶3ω6水平和ω-6/ω-3比例呈增高趋势;C24∶0、C16∶1ω9、C20∶1ω9、C20∶2ω6、C20∶3ω6、C20∶4ω6(AA)、C22∶2ω6、C22∶4ω6、C22∶5ω6、C22∶5ω3和C22∶6ω3(DHA)水平呈下降趋势,总体SFA含量逐渐增加,但无显著性意义;而PUFA尤其是ω-3 PUFA水平显著减少(P0.05)。结论:母乳中的各种脂肪酸随着泌乳时间的延长而不断变化,新生儿喂养及配方奶粉的配制时应考虑母乳中各种脂肪酸含量的微观变化。     

不同加热条件对ω-3鸡蛋中脂肪酸含量的影响

ω-3脂肪酸因其含有较多的不饱和双键而表现出不稳定性,在储存和加工过程中易被氧化.ω-3鸡蛋是一种新型的营养强化食物,以鸡蛋为载体,将ω-3脂肪酸进行营养强化,研究旨在探究ω-3鸡蛋中脂肪酸在加热条件下的变化情况,为ω-3鸡蛋的烹饪加工和食用提供参考.分别以ω-3鸡蛋的带壳鸡蛋和全蛋液为实验对象,将鸡蛋加工成为温泉蛋、溏心蛋及全熟蛋,利用气相色谱法测定其脂肪酸组成和含量,分析比较加热对鸡蛋中脂肪酸含量的影响.研究发现:由于强化方式、养殖方式等多重差异,不同品牌鸡蛋中脂肪酸含量相差较大,经加热处理后,壳蛋个体之间的差异同样表现较为明显,所以最终实验以全蛋液的处理结果为准.与鲜全蛋液相比,温泉蛋的加热过程对ω-3鸡蛋中脂肪酸含量的影响最小,多不饱和脂肪酸含量减少0.08％,必需脂肪酸含量减少0.14％,DHA含量减少1.15％;溏心蛋次之,多不饱和脂肪酸含量减少1.01％,必需脂肪酸含量减少0.55％,DHA含量减少4.23％;全熟蛋脂肪酸组成变化最大,多不饱和脂肪酸含量减少1.22％,必需脂肪酸含量减少1.29％,DHA含量减少5.77％.结果表明:加热过程会使ω-3鸡蛋中的脂肪酸有一定程度的损失,从生蛋、温泉蛋、溏心蛋到全熟蛋,随着成熟程度的增加,鸡蛋中脂肪酸的损失逐渐变大,但损失量总体上比较小,说明加热对ω-3鸡蛋中脂肪酸的影响不大.     

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。     

大麻籽油的特性及研究进展

大麻籽含有约25%～35%的油脂,20%～25%的蛋白质,20%～30%的碳水化合物.以及丰富的微量元素等.大麻籽油中不饱和脂肪酸的含量约为90%,其中必需脂肪酸的含量约80%.ω-6与ω-3多不饱和脂肪酸的比例约为3:1,是理想的人体脂肪酸摄入比例,并且还含有γ-亚麻酸以及丰富的生育酚和植物甾醇.研究表明,大麻籽油在降低胆固醇、抗氧化、清除人体内自由基等方面具有显著的作用,并且是安全无毒的,是一种具有很高利用价值的功能性油脂.     

不同品种禽蛋中不饱和脂肪酸含量分析

目的比较鲜鸡蛋、鸭蛋和鹅蛋不同禽蛋的蛋清和蛋黄中的脂肪酸含量。方法实验分为鸡蛋组、鸭蛋组和鹅蛋组,用气相色谱法对各组禽蛋中的脂肪酸含量进行定量测定。结果 3种禽蛋蛋清中的饱和脂肪酸含量高于蛋黄,多不饱和脂肪酸含量低于蛋黄。ω-3不饱和脂肪酸含量大小为:鸡蛋鸭蛋鹅蛋,强化ω-3脂肪酸的鸭蛋中不饱和脂肪酸含量最高且ω-6/ω-3比值最低;熟鸭蛋的脂肪酸总量和饱和程度与鲜蛋相比没有发生显著性变化。但是咸蛋中饱和脂肪酸含量增加而不饱和脂肪酸含量减少。结论 3种禽蛋中脂肪酸含量不同,经强化的鸭蛋中有益ω-3多不饱和脂肪酸明显高于其他鸭蛋,营养价值最高。     

草鱼肌肉脂肪酸组成及其在冷藏中的含量变化

采用气相色谱-质谱法研究草鱼肌肉脂肪酸组成及其在2～4℃冷藏条件下的变化。结果表明,草鱼肌肉脂肪中不饱和脂肪酸含量较高;饱和脂肪酸(SFA):单不饱和脂肪酸(MLFA):多不饱和脂肪酸(PUFA)的比值为1.08:2.19:1,ω-6/ω-3 PLFA的比值为5.65:1,符合中国营养学会推荐的脂肪酸摄入标准;冷藏过程中,草鱼肌肉总脂肪含量逐渐下降,MUFA和PUFA的相对含量逐渐减少,SFA的相对含量逐渐增多,脂肪酸的降解速率及程度与脂肪酸的不饱和程度呈正相关;脂肪酸的降解与其结构类型有关,ω-3型PUFA降解比ω-6型PUFA更早,但ω-6型PLFA的降解速率更快;部分长链多不饱和脂肪酸(LPUFA)随冷藏时间的延长相对含量略微增加。因此,控制草鱼肌肉脂肪酸在冷藏过程中的降解有利于维持鱼肉制品的营养价值,延长其货架期。     

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.     

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.     

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.     

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.     

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.