维吾尔传统奶制品酸凝乳的营养成分和抗氧化性能的研究

采用食品理化检验分析方法测定了酸凝乳中VA(维生素A)、VC(维生素C)、总黄酮、总生物碱、胆固醇、脂肪、蛋白质、总糖、总酸和9种微量元素质量分数,结果表明,每100g酸凝乳中其含量分别为275.0μg,1.61μg,19.71 mg,43.50μg,81.03μg,12.21 g,12.21 g,0.57 g,19.85 g。用Na2S2O3-I2滴定法测定乙醇提取物、芦丁和VC分别对棉籽油、羊油脂的过氧化(POV)值,对棉籽油的抗氧化效果为:0.02%Rutin0.02%Vc1.0%乙醇提取物0.5%乙醇提取物,对羊油的抗氧化效果为:0.02%Rutin0.02%Vc0.01%乙醇提取物0.05%乙醇提取物。分光光度法测试结果表明酸凝乳乙醇提取物、芦丁和VC清除羟自由基(·OH)能力为0.02%Vc0.02%Rutin0.02%酸凝乳乙醇提取物;酸凝乳中蛋白质和总酸的含量较多,微量元素Ca含量较高,其次是Mg和Zn;酸凝乳具有抗氧化性和清除自由基能力,可有效地延缓油脂的脂质过氧化反应。     

油樟叶多糖抗油脂氧化作用的研究

采用蒽酮-硫酸法测定油樟叶总多糖含量,采用烘箱贮藏法测定油樟叶总多糖抗猪油和菜籽油氧化作用。结果表明,采用蒽酮-硫酸法测得油樟叶中总多糖含量为24.9 mg/g;油樟叶粗多糖对猪油和菜籽油均具有较好抗氧化作用,且呈浓度依赖性;0.20%添加量的油樟叶粗多糖对猪油的抗氧化作用与0.02%BHT相当;0.50%添加量的油樟叶多糖对菜籽油抗氧化作用相当于0.02%BHT;BHT对油樟叶多糖抗猪油和菜籽油氧化作用均有协同增效作用;油樟叶多糖抗猪油氧化作用强于菜籽油。油樟叶多糖具有抗油脂氧化作用,BHT对其有协同增效作用。     

鱼腥草提取物对油脂抗氧化作用研究

以过氧化值为评价指标,采用Schaal烘箱法研究鱼腥草提取物对菜籽油和猪油的抗氧化作用.结果表明:鱼腥草蒸馏水、80％乙醇、石油醚和乙酸乙酯提取物对菜籽油和猪油均具有不同程度的抗氧化作用,80％乙醇提取物对菜籽油和猪油的抗氧化能力均表现最强;鱼腥草80％乙醇提取物分别与柠檬酸和VC复配对菜籽油的抗氧化性有协同增效作用,且VC的增效作用强于柠檬酸;鱼腥草80％乙醇提取物分别与柠檬酸和VC复配对猪油的抗氧化性无协同增效作用.     

金银花不同提取物的油脂抗氧化效果研究

为了比较金银花水提物与醇提物对油脂抗氧化的性质,采用Schall烘箱法评价猪油的过氧化值(PV)变化,同时研究了不同提取物清除DPPH·自由基的效果。结果表明:金银花的2种粗提物均具有一定的抑制油脂过氧化的能力,且总体上醇提物的抗氧化能力优于水提物。金银花醇提物的抗氧化能力与BHT、TBHQ相当。其清除自由基的能力表明:金银花提取物对油脂体系的抗氧化可能是通过清除自由基,从而抑制油脂的氧化自由基链式反应。金银花具有良好的抗氧化能力,可以开发成天然抗氧化剂。     

蜂胶提取物的抗氧化活性研究

以菜籽油和猪油为实验油,采用schall烘箱法测定蜂胶及其乙醇提取物、超临界CO2提取物和CO2残渣醇提物的抗氧化活性,并与其他通用抗氧化剂比较。结果表明:总黄酮浓度0.01%以上的蜂胶提取物均能显著延长油脂氧化诱导期,是高效的油脂抗氧化剂;黄酮类化合物仍是各蜂胶提取物中主要含量成分和主要抗氧化活性成分之一,且随总黄酮浓度0.005%以上一定范围与其整体抗氧化活性呈现量效关系;在相同添加量0.02%(蜂胶提取物均以总黄酮计)和恒温60℃条件下,各抗氧化剂抗氧化效果按强弱顺序排列为:菜籽油中,TBHQ>蜂胶超临界CO2提取物>蜂胶CO2残渣醇提物≥蜂胶乙醇提取物>VE>甘氨酸>蜂胶>BHT;猪油中,TBHQ>蜂胶CO2残渣醇提物≥蜂胶乙醇提取物≥BHT>甘氨酸>蜂胶>蜂胶超临界CO2提取物>VE。本试验结果可望为各蜂胶提取物将来被用作含油脂食品的天然抗氧化剂提供一定的实验数据。     

荸荠皮提取物对食用油脂抗氧化作用研究

采用Schaal烘箱法,以过氧化值为评价指标,研究了荸荠皮提取物对食用油脂的抗氧化作用。结果表明:0.2%荸荠皮提取物对猪油、大豆油、菜籽油均具有一定的抗氧化作用;0.2%荸荠皮提取物对猪油的抗氧化作用弱于0.2%抗坏血酸,强于0.2%柠檬酸,8 d前的抗氧化效果强于0.2%BHT;0.2%、0.6%、1.2%、1.8%荸荠皮提取物对猪油的抗氧化作用呈剂量-效应关系;0.1%荸荠皮提取物分别与0.1%抗坏血酸、0.1%柠檬酸、0.1%酒石酸复配对猪油的抗氧化性有协同增效作用。     

枳椇子乙醇提取物对猪油抗氧化能力研究

以猪油为试验材料,采用烘箱法评价不同添加量枳椇子乙醇提取物对猪油的抗氧化能力,并与抗坏血酸棕榈酸酯、维生素E、特丁基对苯二酚进行比较分析。结果表明：在猪油氧化诱导期,0.1%乙醇提取物与0.02%特丁基对苯二酚有相当的脂质抗氧化能力,说明枳椇子乙醇提取物具较强油脂抗氧化能力;在猪油氧化的发展期,不同添加量乙醇提取物有不同程度的促进氧化的作用。同时对各抗氧化剂的抗氧化机理进行了探讨。     

野玫瑰色素对油脂的抗氧化作用

以猪油和菜籽油作为底物,采用烘箱贮藏法测定油脂的POv值,研究野玫瑰天然色素时油脂的抗氧化活性,结果表明,野玫瑰色素具有一定的抗油脂氧化能力,当色素的添加量分别为猪油和菜籽油质量的0.03%和0.02%时.效果最好,而且柠檬酸与抗坏血酸对色素的抗氧化性有协同增效作用,抗坏血酸的协同作用更好.     

芹菜叶提取物抗氧化作用研究

以索氏提取法用60%乙醇提取芹菜叶中的黄酮类物质,分别采用生化试剂盒法测定其总抗氧化能力及对羟自由基(·OH)、超氧阴离子自由基(O2·)的清除能力,另对不同油脂的抗氧化性能进行检测,评价芹菜叶提取物的体外抗氧化作用。结果表明:芹菜叶乙醇提取物具有较强的抗氧化作用和清除·OH、O2·的能力,并且随提取物质量浓度增大,其总抗氧化能力及清除自由基能力增强,表现出明显的量效关系;芹菜叶乙醇提取物有显著的防止油脂氧化的作用,其效果优于VC。     

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.     

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.     

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.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.