改良的DPPH与ABTS自由基法评价不同葡萄籽油抗氧化能力

本研究采用改良的1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picryhydrazyl,DPPH)法和2,2'-联氮双-(3-乙基苯并噻唑林-6-磺酸)二胺盐[2,2'-azinobis(3-ethylbenzothi azoline-6-sulfonic acid)ammonium salt,ABTS]法测定不同方法提取葡萄籽油极性部分、非极性部分及全油的抗氧化能力,测定不同葡萄籽油多酚含量,研究多酚与葡萄籽油极性部分抗氧化能力的相关性。热榨毛油与溶剂法毛油在经过精炼后多酚含量和抗氧化能力显著降低;在溶剂法精炼油、热榨法精炼油、低温压榨油、超临界CO_2萃取葡萄籽油中,低温压榨油极性部分清除DPPH与ABTS自由基的能力最强,低温压榨油的多酚含量最高,超临界CO_2萃取葡萄籽油非极性部分与低温压榨油全油的DPPH与ABTS自由基清除能力最强;各不同葡萄籽油总酚含量与极性部分DPPH和ABTS自由基的清除能力具有显著的正相关性。     

4 个葡萄品种葡萄籽冷榨油的性质与体外抗氧化活性

目的：评价4 种葡萄籽冷榨油脂肪酸组成、总酚含量及体外抗氧化活性。方法：收集单品种葡萄籽榨油,气相色谱法测定脂肪酸组成,Folin-酚法测定总酚含量,用1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picryhydrazyl,DPPH）法、2,2’-联氮双-（3-乙基苯并噻唑林-6-磺酸）二胺盐（2,2’-azinobis(3-ethylbenzothi azoline-6-sulfonic acid)ammonium salt,ABTS）法、Fenton反应和总抗氧化能力法分析其体外抗氧化能力。结果：4 个品种葡萄籽冷榨油均富含亚油酸（72.77%～77.36%）,不饱和脂肪酸含量为88.12%～91.06%;总酚含量为60.77～100.53 μg GAE/g,爱格丽葡萄籽冷榨油总酚含量最高,其次是北冰红、媚丽、赤霞珠葡萄籽冷榨油;4 个品种的葡萄籽冷榨油都有良好的清除DPPH自由基和ABTS＋·的能力,且随着葡萄籽冷榨油浓度的增大,清除能力增强,清除DPPH自由基的IC50变化范围为10.19～13.82 mg/mL,清除ABTS＋·的IC50变化范围为11.62～19.25 mg/mL;清除羟自由基（·OH）的能力范围为13.18～27.08 U/mL;总抗氧化能力范围为1.08～3.68 U/mL。4 个品种的葡萄籽冷榨油的体外抗氧化能力强弱顺序为爱格丽＞北冰红＞媚丽＞赤霞珠。     

小叶女贞籽油脂肪酸组成及对自由基的清除作用

以小叶女贞种子为原料,采用超临界CO_2萃取小叶女贞籽油,用气相色谱-质谱联用技术(GC-MS)分析小叶女贞籽油的脂肪酸组成,并用分光光度法测定小叶女贞籽油对ABTS自由基和DPPH自由基的清除作用。结果表明:小叶女贞籽油中含8种脂肪酸,主要含有油酸(59.49%)、亚油酸(25.47%)和棕榈酸(9.67%),不饱和脂肪酸含量达85.40%;小叶女贞籽油对ABTS自由基和DPPH自由基有较好的清除能力,IC50分别为(34.32±0.73)μg/m L和(43.63±0.91)μg/m L。     

微波预处理对压榨南瓜籽油品质的影响

以南瓜籽仁为原料,研究了微波预处理对压榨南瓜籽油品质的影响。结果表明：随着微波功率的增加和处理时间的延长,压榨南瓜籽油的酸值变化不大;当微波功率为350 W和550 W时,随着处理时间的延长,南瓜籽油过氧化值总体呈增长趋势,而微波功率为700 W时,南瓜籽油过氧化值则呈先上升后下降的趋势。微波预处理能提高南瓜籽油中总酚、甾醇、总生育酚的含量,分别在550 W微波处理12、9、9 min时达最高,为1 352.7 mg/kg、2.54 mg/g和56.95 mg/100 g,比微波处理前分别提高了87.61%、29.59%和15.17%。同时微波预处理也能提升南瓜籽油的氧化诱导时间、DPPH自由基清除能力和ABTS自由基清除能力,在550 W微波处理9 min时,氧化诱导时间、DPPH自由基清除率、ABTS自由基清除率最高,分别为5.83 h、295.11 μmol/100 g和724.35 μmol/100 g,比微波处理前分别提高了57.57%、33.96%和64.46%。适当的微波预处理可以显著增加南瓜籽油中油脂伴随物含量,提高油脂的氧化稳定性和抗氧化能力。     

油梨仁提取物的体外抗氧化活性研究

试验研究了油梨仁提取物的体外抗氧化活性。以VC为对照品,采用羟自由基清除法、超氧阴离子自由基清除法、DPPH自由基清除法、ABTS自由基清除法以及铁氰化钾还原法评价油梨仁提取物的体外抗氧化活性。结果表明,油梨仁提取物对超氧阴离子自由基和DPPH自由基具有较强的清除作用,其IC50分别为0.025 mg/m L和0.086mg/m L,且其还原能力与VC相当;而对羟自由基和ABTS自由基的清除能力相对较弱。     

山楂籽油化学成分及抗氧化活性的研究

对山楂籽油的化学成分、脂肪酸组成进行了研究,测定了山楂籽油中角鲨烯、维生素E、总黄酮、总多酚含量,利用DPPH和ABTS法评价山楂籽油的体外抗氧化活性。结果表明:通过GC-MS,初步确认了23种化学成分,其中亚油酸、油酸及其脂类、角鲨烯为主要成分。通过对山楂籽油的脂肪酸分析,鉴别出14种脂肪酸,主要为不饱和脂肪酸(89%);测定角鲨烯含量为(236. 64±13. 20) mg/kg,HPLC法分别测定4种亚型维生素E的含量,含量最高的为γ-生育酚,达到(51. 92±2. 53) mg/100 g,测定了总多酚和总黄酮含量,分别为(424. 59±11. 25)、(103. 33±5. 86) mg REs/100 g DW,这些物质均有很好的抗氧化活性。利用DPPH和ABTS法评价了山楂籽油的抗氧化活性,结果显示山楂籽油对DPPH和ABTS有很好的清除能力,清除率均达到90%以上。     

GC-MS结合PLSR模型用于新疆小白杏杏仁油抗氧化性能的研究

试验采用超临界萃取、机械压榨、索氏提取和超声波辅助提取4种不同方法制备新疆小白杏杏仁油,通过GC-MS对4个不同方法制备的小白杏杏仁油样品中的脂肪酸、植物甾醇及VE等多种生物活性物质组分进行分析鉴定,检测出33种存在明显差异的活性成分(P0.05)。对上述4个样品进行抗氧化试验,结果表明不同方法制备的样品对DPPH自由基、羟基自由基、超氧阴离子自由基及ABTS自由基均存在差异性的清除能力,通过半抑制浓度(IC50)对照分析发现超临界萃取及机械压榨法制备样品对相关自由基的清除能力效果较为显著,同时结合PLSR模型和差值系数分析初步确定对自由基清除的关键物质。     

制油工艺对亚麻籽油品质及脂质伴随物含量的影响

考察冷榨、微波辅助冷榨、加速溶剂萃取、超临界CO2萃取、亚临界流体萃取5种不同制油工艺对亚麻籽油的得率、理化品质、典型脂质伴随物含量、体外抗氧化活性和氧化稳定性的影响。结果表明:微波辅助冷榨可显著提高亚麻籽油得率,与其他工艺相比增加了4.3%~10.66%(P0.05)。不同制油工艺亚麻籽油的理化品质虽有一定差异,但均符合GB/T 8235—2019《亚麻籽油》要求。超临界CO2萃取对α-亚麻酸富集效果较好(54.06%),相比于其他工艺增加了3.70%~5.31%(P0.05)。制油工艺对亚麻籽油中典型脂质伴随物含量具有特异性影响,其中加速溶剂萃取和微波辅助冷榨油脂中生育酚、类胡萝卜素、叶绿素、黄酮和磷脂的含量较高。亚临界流体萃取油脂中植物甾醇总量较高(429.78 mg/100 g),相比于其他工艺增加了5.07%、9.34%、15.57%、30.26%(P0.05)。超临界CO2萃取中总酚含量较高(13.60 mg/100 g),相比于其他工艺增加了7.77%~68.53%(P0.05)。此外,不同制油工艺亚麻籽油的体外抗氧化活性和氧化稳定性也具有显著性差异(P0.05),加速溶剂萃取和微波辅助冷榨油脂的氧化稳定性较好,1,1-二苯基-2-三硝基苯肼自由基清除能力较强。冷榨、亚临界流体萃取和超临界CO2萃取油脂的氧化稳定性相对较差,但超临界CO2萃取油脂的铁离子还原能力较强。本研究系统地比较了不同制油工艺亚麻籽油的理化品质和典型脂质伴随物含量的差异,研究结果将对亚麻籽油的分类加工和靶向制取提供一定理论依据。     

两种真姬菇不同溶剂提取物的抗氧化活性研究

研究两种真姬菇不同溶剂提取物的抗氧化活性和多酚含量。制备真姬菇粗提物、正己烷萃取物、乙酸乙酯萃取物、正丁醇萃取物与水萃取物,分析它们的抗氧化活性与测定它们的多酚含量。结果表明:闽真2号正己烷萃取物的总抗氧化能力最好,乙酸乙酯萃取物清除DPPH自由基能力最强,正丁醇萃取物清除ABTS自由基能力最强;闽真3号乙酸乙酯萃取物的总抗氧化能力、清除DPPH与ABTS自由基能力均最好。相关性分析结果表明,真姬菇多酚含量与DPPH自由基清除能力具有一定的相关性。综合考虑抗氧化活性与萃取率,正己烷萃取物与乙酸乙酯萃取物可被作为天然抗氧化剂应用于食品科学领域。     

核桃分心木提取物的抗氧化活性及其对油脂氧化稳定性的影响

为充分利用核桃副产品资源,该研究采用超声辅助乙醇提取核桃分心木抗氧化活性成分,初步研究核桃分心木提取物的抗氧化活性。根据DPPH自由基清除能力和总酚、总黄酮含量测定结果,对核桃分心木的不同浓度乙醇溶液提取物及4种不同极性溶剂萃取物进行抗氧化活性评价。测定正丁醇萃取物DPPH自由基、ABTS+自由基和羟基自由基的清除能力,并以菜籽油为底物,研究该萃取物对菜籽油氧化稳定性的影响。结果表明：核桃分心木60%乙醇溶液提取物抗氧化活性较高,且抗氧化活性较强的物质主要集中在正丁醇萃取相。正丁醇萃取物DPPH自由基、ABTS+自由基清除能力的IC50值均为0.010 mg/mL。油脂氧化稳定性大小顺序依次为0.02%特丁基对苯二酚>0.05%正丁醇萃取物>0.04%正丁醇萃取物>0.03%正丁醇萃取物>0.02%VC>0.02%正丁醇萃取物>0.01%正丁醇萃取物>空白对照。添加0.04%正丁醇萃取物的油脂,其抗氧化活性与添加0.02%VC相当。说明核桃分心木提取物具有较好抗氧化活性,可作为天然抗氧化活性物质的良好资源。     

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.     

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.     

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.