干红葡萄酒酿造过程中白藜芦醇的变化

采用赤霞珠、玫瑰香为原料,单品种发酵酿造干红葡萄酒,发酵期间葡萄酒中的白藜芦醇的变化情况直接采用HPLC直接进样方法检测。主发酵温度控制在26℃左右,主发酵前添加60mg／L的二氧化硫,在后发酵时补充加入10mg／L的SO2,能有效降低白藜芦醇的损失。两个单品种酿造的干红葡萄酒经过苹果酸一乳酸发酵后白藜芦醇总量都略微提高,分别达到4．92mg／L和3．87mg／L。     

宁夏葡萄酒中白藜芦醇含量的高效液相色谱快速测定

建立高效液相色谱法测定葡萄酒中白藜芦醇的方法,考察直接进样法的检测波长、洗脱强度、流动相pH值、柱温、样品pH值等因素对酒样分离的影响,建立HPLC检测葡萄酒中白藜芦醇的方法,相关系数r为0.999 9,线性范围为1 mg/L~20 mg/L,精密度、稳定性、回收率试验的RSD分别为1.16%、2.9%和1.25%,酒样检测发现白藜芦醇的含量随酒的年份和品种变化,品种间比较结果为:蛇龙珠最优,梅鹿辄、赤霞珠、霞多丽次之,贵人香最低,其中蛇龙珠含量高达6 mg/L。     

液相色谱检测葡萄酒中白藜芦醇的含量

试验基于高效液相色谱建立一种快速检测葡萄酒中白藜芦醇含量的方法。该液相方法采用的色谱柱为ODS-C18(4.6 nm×250 nm,5μm),检测波长306 nm,流速1.0 m L/min,进样量20μL,流动相为甲醇-0.5%磷酸水溶液(体积比40∶60)。结果表明:葡萄酒中白藜芦醇含量在0~5 mg/L范围内呈现良好的线性关系(R2=0.999 3),1.00 mg/L白藜芦醇加标回收率范围为96.0%~99.0%,检出限为0.90 mg/L,检测精密度为2.70%,且准确性较高。该研究方法具有良好的潜力,能够快速、准确检测葡萄酒中白藜芦醇的含量测定,且能为葡萄酒的品质评价提供依据。     

进口葡萄酒理化指标及残留污染物监控研究

选取了9个国家24种进口葡萄酒,对其理化指标及残留污染物进行分析检测。抽检的24批次葡萄酒结果表明,普通理化指标检测结果为:酒精度在8°~15°之间,甲醇含量为0~190 mg/L,二氧化硫的含量在61.9 mg/L~237.8 mg/L;重金属检测结果为:Cu、Pb等指标为未检出,Fe的残留量在0.56 mg/L~4.91 mg/L;有害污染物检测结果为:邻苯二甲酸二丁酯等3种塑化剂均为未检出;食品添加剂检测结果为:选取的诱惑红、苋菜红等8种色素均未检出,防腐剂苯甲酸的残留量为未检出,山梨酸的残留量为6 mg/L~159 mg/L;菌落数等微生物检测指标均为未检出。     

添加‘丹菲特’单品种葡萄酒对‘赤霞珠’葡萄酒酚类物质和颜色的影响

该研究以‘赤霞珠’单品种干红葡萄酒为基酒,添加不同比例的‘丹菲特’单品种干红葡萄酒,旨在通过改变‘赤霞珠’干红葡萄酒的酚类物质组成,改善其颜色表现。利用超高效液相色谱-三重四极杆串联质谱（UPLC-MS/MS）对葡萄酒中的酚类物质进行测定,并结合CIELAB颜色评价体系对调配葡萄酒的颜色品质进行分析。结果表明,‘丹菲特’单品种干红葡萄酒的添加比例在20%和25%时对‘赤霞珠’干红葡萄酒的颜色改善有较好的效果,能够显著提高红色色调,降低黄色色调,同时显著提高调配葡萄酒的类黄酮类物质含量,其中添加比例为20%的葡萄酒黄烷醇含量最高（25.27 mg/L）,添加比例为25%的葡萄酒花色苷（371.72 mg/L）和黄酮醇类物质（16.23 mg/L）含量较高。     

赤霞珠葡萄酒酿造过程中白藜芦醇的变化

赤霞珠干红葡萄酒发酵期间葡萄酒中的白藜芦醇的变化情况采用HPLC直接进样方法检测。主发酵温度控制在26℃~28℃,主发酵前添加60 mg/L的二氧化硫,在后发酵时补充加入10 mg/L的SO2,能有效的降低白藜芦醇的损失。经过苹果酸-乳酸发酵后白藜芦醇总量略微有点提高,达到4.98 mg/L。     

不同单品种葡萄酒中白藜芦醇以及白藜芦醇苷含量的研究

采用高效液相色谱法测定了广西地区几个酿酒品种和野生品种的单品种葡萄酒中的白藜芦醇及其糖苷的含量。结果表明,巨峰冬葡萄酒以及两个野生品种G203和A3051的葡萄酒中白藜芦醇及其糖苷含量较高,其总含量分别达到1.505 mg/L、1.1728 mg/L和0.9389 mg/L。     

不同过滤方式对红葡萄酒中白藜芦醇含量的影响

本文采用反相高效液相色谱(RP-HPLC)方法同时检测葡萄酒中重要功效成分白藜芦醇及其糖苷的顺反式四种异构体,对比了错流微孔膜过滤(Cross Microflow Filtration,CMF)和硅藻土过滤(kieselguhr Filtration,KF)后红葡萄酒中白藜芦醇含量的变化,发现1)不同品种葡萄酿造的葡萄酒白藜芦醇含量差异很大,赤霞珠葡萄酒中白藜芦醇含量为4.63 mg/L,高于梅鹿辄葡萄酒含量一倍(2.05 mg/L);2)CMF过滤对红葡萄酒中白藜芦醇的保留率达到103.90%,优于硅藻土过滤(保留率为93.08%);3)硅藻土过滤后白藜芦醇反式异构体含量降低,其中反式白藜芦醇糖苷的损失较大,保留率为78.87%.     

葡萄酒中单宁含量调查与口感关系的分析

目的 通过测定不同产地、不同品种、不同类型的524支进出口葡萄酒中单宁的含量,进一步分析葡萄酒中的单宁与口感质量的关系。方法 将样品用蒸馏水稀释100倍,以没食子酸为标准物质,采用分光光度法对葡萄酒中的单宁进行定量分析。结果 该方法简单可靠,试剂用量少,操作方便,快速准确,仪器设备简单。在0 mg/L~5.0 mg/L范围内线性关系良好,相关系数为0.9999;单宁添加回收率在86.7%~120%之间,平均回收率达103.8%。产地方面,意大利的红葡萄酒中单宁含量最高,平均为2.70 g/L;品种方面,黑皮诺酿造的红葡萄酒中单宁含量较多,平均含量为3.15 g/L;国产葡萄酒方面,云南产区的葡萄酒中单宁含量相对较高,平均为2.51 g/L。结论 葡萄酒中单宁含量与葡萄品种、产地、酒类型有关;柔顺指数超过5.0的葡萄酒,口感与品质良好。     

赤霞珠和蛇龙珠不同比例混合发酵的葡萄酒质量分析

为探讨单品种发酵与混合发酵对葡萄酒质量的影响,本研究在同一实验条件下,将宁夏回族自治区青铜峡市甘城子的赤霞珠与蛇龙珠单品种发酵的葡萄酒作为对照,以7:3、5:5、3:7混合后发酵的葡萄酒作为处理组,采用同一酿造工艺酿造而成,通过分析5种葡萄酒的理化指标(包括总糖、总酸、酒精度、p H、总酚、单宁、灰分)和感官品评的方法,来对葡萄酒的质量做出评价与分析。结果表明:赤霞珠单品种酒的总酸、单宁、总酚的含量最高,分别为7.65 g/L、1183.16 mg/L、1971.0 mg/L;其次是赤霞珠与蛇龙珠以7:3混合的,分别是6.9 g/L、1179.28 mg/L、1714.1 mg/L;从外观,香气、口感、典型性来看,得分最高的是赤霞珠与蛇龙珠以7:3混合酿造的葡萄酒,总分为81分;结合总酸、单宁、总酚含量与外观、香气、口感、典型性得出:赤霞珠与蛇龙珠以7:3混合发酵酒最佳。     

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.