水剂法提取澳洲坚果油的化学成分及其抗氧化活性研究

采用水剂法从烘干的澳洲坚果仁中提取仁油,先对其基本理化性质进行分析,再通过红外、气相和液相色谱法对坚果油的红外特性、脂肪酸组成、生育酚、磷脂、甾醇进行分析,并通过测定其氧化诱导时间和清除DPPH自由基的能力来综合评价澳洲坚果油的抗氧化能力。结果表明:水剂法提取的澳洲坚果油的过氧化值、酸价、碘值、皂化值、折光率、水分及挥发物含量分别为0.59 mmoL/kg、0.28 mg KOH/g、74.21g/100g、198.78mg KOH/g、1.466 8、0.36%;红外谱图显示澳洲坚果油具有坚果油的特征吸收;脂肪酸分析发现其不饱和脂肪酸含量为83.45%,其中棕榈油酸和油酸含量分别为17.25%和61.44%;甾醇含量为55.51 mg/100g;总酚酸含量为31.87 mg/100g;磷脂和生育酚均未检出;澳洲坚果油的氧化诱导时间为11.44h,其清除DPPH自由基的能力达89.84%,具有良好的抗氧化能力。     

不同制油工艺亚麻籽油的储藏性能研究

利用Schaal烘箱法来动态检测亚麻籽油的储藏品质,测定了酸价、过氧化值、K232、K270值等理化指标以及总酚、维生素E、甾醇等营养成分含量的变化,同时对不同制油工艺亚麻籽油的微量营养成分含量和理化指标进行相关性分析。结果表明:亚麻籽油在储藏期间,过氧化值、酸价、K232值开始缓慢增长,后快速增长;K270值持续增长;多种营养成分在储藏期间均出现不同程度的消耗,在本试验条件下,微波制油工艺获得的亚麻籽油具有最好的储藏性能;亚麻籽油在储藏期间的营养成分含量与酸价、过氧化值、K232和K270值密切相关,进而共同影响亚麻籽油的品质。     

奇亚籽油储藏稳定性研究及货架期预测

为研究奇亚籽油储藏稳定性,以液压法制备的奇亚籽油为原料,探讨储藏温度、氧气和光照条件对奇亚籽油过氧化值、酸价、K₂₃₂、K₂₆₈和TBA的影响,并应用一级动力学模型结合Arrhenius方程建立过氧化值、酸价两个氧化指标随储藏温度、储藏时间变化的货架期预测模型,预测奇亚籽油货架期。结果表明：奇亚籽油的氧化稳定性受光照、氧气和温度的影响,在避光、密封、低温的储藏条件下能有效降低过氧化值、酸价等的增长速率,延长储藏时间;通过模型推算得出密封、避光条件下奇亚籽油在25℃条件下的货架期为94 d。     

基于微波预处理压榨文冠果油储藏期间的品质研究

利用Schaal烘箱法,研究测定了由微波预处理种仁冷榨制取的文冠果油储藏期间酸价、过氧化值、p-茴香胺值、生育酚含量、脂肪酸组成及含量的变化,评价了微波预处理对油脂氧化稳定性的影响,并对文冠果油理化指标进行了相关性分析。结果表明:文冠果油在储藏期间,过氧化值和K_(232)在前期快速增高,中期趋于平缓,后期又快速增长;酸价、p-茴香胺值及K_(270)则持续增长;生育酚含量与氧化诱导时间在前、后期快速降低,中期降低较缓慢;不饱和脂肪酸与饱和脂肪酸的比值降低;相关性分析表明文冠果油在储藏期间的氧化稳定性与生育酚含量及过氧化值、酸价、p-茴香胺值、K_(232)、K_(270)密切相关。此外,适当的微波预处理有助于增强文冠果油的氧化稳定性。     

常温储藏下冷、热榨花生毛油品质变化的研究

通过探讨油脂酸价、过氧化值、Euv268值和羰基值等指标,对冷、热榨花生毛油在常温储藏下油脂品质的变化进行了分析。结果表明,与冷榨花生毛油相比,热榨毛油的酸价、过氧化值和羰基值等指标偏高,热榨毛油氧化的程度较高。随着储藏时间的延长,花生毛油中的油脂氧化速度先慢后快,过氧化值、Euv268值和羰基值先降至较低水平后,然后缓慢升高。常温储藏30 d内,冷榨法花生毛油品质优于热榨法。     

提取方法对澳洲坚果油的化学成分及其抗氧化活性影响研究

本文旨在研究不同提取方法(水剂法、压榨法、溶剂法)对澳洲坚果油主要理化性质、活性成分、脂肪酸组成和红外光谱的影响,并采用DPPH自由基清除能力和氧化稳定性来综合评价澳洲坚果油的抗氧化活性。结果表明:三种提取方法得到的澳洲坚果油的理化性质(过氧化值、酸价、皂化值、碘值等)均符合国家食用油标准;与溶剂法和水剂法相比,压榨法得到的澳洲坚果油表现出较好的产品特性,其总酚酸含量((41.82±0.73)mg/100 g)、不饱和脂肪酸含量(83.67%)最高,且其氧化诱导时间((13.87±0.37)h)最长,清除DPPH自由基能力(46.70%)最强。红外谱图显示不同提取方法得到的澳洲坚果油均具有坚果油的特征吸收,且提取方法对其分子结构没有影响;通过分析不同提取方法得到的澳洲坚果油的品质,可为提取高品质澳洲坚果油奠定理论基础,同时也为澳洲坚果油的工业化生产提供了参考依据。     

炒籽温度对压榨亚麻籽油品质的影响

采用不同温度对亚麻籽进行炒籽并压榨制油,对压榨亚麻籽油的感官品质、理化指标及营养成分进行分析,研究炒籽温度对压榨亚麻籽油品质的影响。结果表明:随着炒籽温度的升高,压榨亚麻籽油的气味从坚果芳香过渡到严重焦糊味,色泽加深,在195℃炒籽45 min时形成热榨亚麻籽油特有的浓香型风味;营养成分如VE、总酚以及甾醇含量随炒籽温度升高而逐渐减少,在255℃炒籽45 min时,3种营养成分的损失率分别为75. 7%、76. 5%和88. 9%;酸价、过氧化值、茴香胺值、K232值、K270值随炒籽温度升高而增加,且炒籽温度对压榨亚麻籽油中主要脂肪酸含量有显著影响;适当炒籽对压榨亚麻籽油的氧化稳定性是有利的;高温炒籽压榨亚麻籽油中的营养成分含量与其理化指标密切相关,进而共同影响压榨亚麻籽油的品质。     

化学和物理精炼工艺对葡萄籽油氧化劣变品质的影响

为了研究化学和物理精炼工艺对葡萄籽油氧化裂变品质的影响,分别采用化学和物理工艺精炼葡萄籽原油,探讨反式脂肪酸的变化规律,以及不同精炼阶段油脂的酸价、过氧化值、p-茴香胺值和VE含量变化。结果表明:葡萄籽油经化学精炼酸价降至(0.20±0.016)mg KOH/g,葡萄籽油的过氧化值和p-茴香胺值降低,反式脂肪酸质量分数增加至(0.36±0.001 4)%,VE损失了37%~43%。对葡萄籽原油进行物理精炼,240℃条件下真空脱酸6 h,酸价降至(0.19±0.029)mg KOH/g,过氧化值降低、p-茴香胺值升高,反式脂肪酸质量分数增至(0.91±0.001 3)%,VE损失了50.69%。比较得知,物理精炼过程相对于化学精炼对葡萄籽油品质的影响较大。     

温度及光照对亚麻籽油贮藏稳定性影响研究

为研究亚麻籽油贮藏稳定性,以初榨亚麻籽油为原料,测定贮藏过程中油脂的过氧化值、酸价、K232、K270和TBA值,探讨了温度和光照对贮藏过程中亚麻籽油品质的影响,采用主成分分析法进行数据处理。结果表明,亚麻籽油的氧化稳定性随温度的升高明显降低,60℃贮藏条件下亚麻籽油的过氧化值增长速率分别是50、40、30℃的3.02、5.88、22.41倍,酸价增长速率分别是50、40、30℃的2.22、10.60和29.96倍。不同光照条件下,以避光贮藏的亚麻籽油品质最佳,其各项品质指标均优于日光灯和自然光下贮藏的亚麻籽油。主成分分析结果表明,第一主成分可以解释各品质指标89.40%的信息,其中,过氧化值对第一主成分的贡献最大,其次是TBA。     

充氮储藏的菜籽油食用期品质变化

以不添加抗氧化剂的一级菜籽油为原料,酸价、过氧化值、p-茴香胺值为监测指标,在模拟家庭食用期储藏条件下,探讨了充氮储藏的菜籽油(2. 5 L/桶)在3个月食用期内的品质变化规律。结果表明:充氮储藏的菜籽油在3个月的食用期内酸价(KOH)未超过一级菜籽油的限量值0. 2 mg/g;充氮储藏的菜籽油比空白对照组的过氧化值达到5. 0 mmol/kg的时间延长了20 d;充氮储藏的菜籽油p-茴香胺值的变化较为平缓,在前30 d内变化不大。充氮储藏提高了菜籽油的氧化稳定性,该储藏方法可以成为菜籽油的一种新型绿色的储藏技术。     

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.     

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.