黄连花茶加工工艺及其抗氧化作用研究

以黄连的花薹为原料,研究了黄连花茶的加工工艺及其抗氧化活性。结果表明,黄连花薹经杀青、冷却后,干燥,包装制得的黄连花茶风味清香、复水性好。采用霍恩氏法,对花茶的急性毒性(LD50)进行测定,21.5g/kg·BW剂量下,实验动物未发现死亡及异常;大于15g/kg·BW剂量,属无毒。水浸出物对羟自由基(·OH)和过氧化氢(H2O2)均具有清除作用。     

正交实验设计法优化超声复合酶提取甜茶苷工艺

采用正交设计法优化甜茶苷提取的工艺,在单因素的实验基础上选择料液比、乙醇浓度、超声功率和复合酶(纤维素酶∶果胶酶∶木瓜蛋白酶=1∶1∶1)酶解p H,每个因素选取3个水平,进行正交实验,根据正交设计的原理和分析方法,结果得出甜茶苷提取的最佳工艺条件:复合酶用量为2.6%,酶解p H4.0,甜茶粉末与乙醇的料液比为1∶20(w/v),乙醇浓度为40%(v∶v),超声功率50 W,在甜茶粉末过40目筛,用复合酶酶解30 min,温度45℃下,超声提取30 min,重复提取2次,甜茶苷的提取率可达66.4%±0.9%,含量是110.7 mg/g。     

苦丁茶、金樱子、杭白菊复合袋泡茶的研制

用苦丁茶、杭白菊与金樱子混合制成袋泡茶,产品口感良好, VC含量高。最佳配比为：苦丁茶∶金樱子∶杭白菊 =40∶ 10∶ 1, Vc含量为 896.21mg/100g,是绿茶 VC含量的 2.99～ 8.96倍,是红茶 VC含量的 22.40～ 49.79倍。     

刺梨、苦丁茶、杭白菊复合袋泡茶的研制

用苦丁茶、杭白菊与刺梨混合制成袋泡茶，产品口感良好，Ｖｃ含量高。最佳配比为：刺梨∶苦丁茶∶杭白菊＝１０∶４０∶１，Ｖｃ含量为１６２９．４８ｍｇ／１００ｇ，是绿茶Ｖｃ含量的５．４～１６．３倍，是红茶Ｖｃ含量的４０．７～９０．５倍。     

葛根袋泡茶研制及风味成分分析

以野葛根为原料,杭白菊、枸杞子为辅料制得袋泡茶,以异黄酮含量和感官评价为考察指标,研究配料比（葛根∶枸杞子∶杭白菊）、冲泡时间、冲泡温度和用水量对葛根袋泡茶品质的影响,采用综合评分法,通过U10（1010）均匀设计优化葛根袋泡茶配方和沏茶工艺参数。结果表明,葛根袋泡茶的最优工艺：原辅料比（葛根∶杭白菊+枸杞子）为2∶1（g/g）,辅料比（杭白菊∶枸杞子）为 1.5∶1（g/g）,冲泡时间 9 min,冲泡温度 65 ℃,冲泡料水比 1∶25（g/mL）。葛根袋泡茶提取液与抗坏血酸（VC）清除 ABTS+自由基的 IC50值分别为（1.136±0.010）、（1.228±0.011）mg/mL,呈剂量效应关系,葛根袋泡茶有较强的抗氧化性。顶空固相微萃取-气质联用（headspace solid phase microextraction combined with gas chromatography-mass spectrometry,HS-SPME-GC-MS）试验结果表明,左旋乙酸冰片酯、（Z）-乙酸菊酯、左旋龙脑是葛根袋泡茶的主要挥发性物质成分。     

两步法提取杭白菊精油工艺条件的优化

为提升杭白菊的经济附加值,探索工业化生产杭白菊精油的工艺,本研究先用索氏提取法提取杭白菊中的粗脂肪,再用水蒸气蒸馏法精制粗脂肪中的精油,分两步提取杭白菊精油。在单因素实验的基础上,选取样品粒度、超声时间、料液比和蒸馏时间,设计4因素3水平实验,采用Box-Behnken中心组合设计原理优化杭白菊精油的提取条件,结果表明,采用两步法提取杭白菊精油的最佳条件为:样品粒度80~100目,超声时间30 min,料液比(g/m L)1∶11,蒸馏时间9 h,在该条件下杭白菊精油的提取率为4.8 m L/kg。本方法可作为工业化提取杭白菊精油的技术基础。     

金花甜茶浸提条件的研究

为确定金花甜茶的浸提条件,采用热水浸提的方法,通过单因素试验和正交试验,以金花甜茶中的甜茶素和茶多酚的浸提率为评价指标进行研究。结果表明,最佳浸提条件为:浸提时间60 min,料液比为1∶70(g/mL),浸提温度为85℃。     

反相高效液相色谱法同时测定黄连花薹及黄连花茶中6种生物碱的含量

目的采用反相高效液相色谱法,建立盐酸药根碱、非洲防己碱、盐酸表小檗碱、盐酸黄连碱、盐酸巴马汀和盐酸小檗碱共6种生物碱的同时测定方法,并测定其在黄连花薹和黄连花茶中的含量。方法采用反相高效液相色谱法。Xtimate~(TM)C_(18)色谱柱(4.6 mm×250 mm,5μm、);流动相A相30 mmol/L碳酸氢铵水溶液(含有0.7%氨水、0.1%三乙胺),B相乙腈,体积比为72:28,流速为1 mL/min;检测波长345 nm;柱温为25℃;进样体积为20μL。结果在一定的浓度范围内,6种生物碱浓度与峰面积之间的线性关系良好,其检测精密度、稳定性、重复性及加样回收率的RSD值均在3%以内。测得两个品牌黄连花茶中6种生物碱含量差异不大,对4个不同来源的黄连花薹样本而言,其中盐酸黄连碱和盐酸巴马汀的含量差异也不大,但盐酸药根碱、非洲防己碱、盐酸表小檗碱和盐酸小檗碱的含量却有较大差异。结论该方法具有分析速度快、灵敏度高、重现性好等特点,该方法的普及和应用将会为黄连花茶等系列深加工产品提供一个从原料到产品的质量控制方法。     

反相高效液相色谱法同时测定黄连花薹及 黄连花茶中6种生物碱的含量

目的 采用反相高效液相色谱法,建立盐酸药根碱、非洲防己碱、盐酸表小檗碱、盐酸黄连碱、盐酸巴马汀和盐酸小檗碱共6种生物碱的同时测定方法,并测定其在黄连花薹和黄连花茶中的含量。 方法 采用反相高效液相色谱法。Xtimate TM C18色谱柱( 4.6 mm?250 mm, 5 μm);流动相A相30 mmol/L碳酸氢铵水溶液 (含有0.7%氨水、0.1%三乙胺),B相乙腈,体积比为72:28,流速为 mL/min;检测波长345 nm;柱温为25 ℃;进样体积为20 μL。 结果 在一定的浓度范围内,6种生物碱浓度与峰面积之间的线性关系良好,其检测精密度、稳定性、重复性及加样回收率的RSD值均在3%以内。测得两个品牌黄连花茶中6种生物碱含量差异不大,对4个不同来源的黄连花薹样本而言,其中盐酸黄连碱和盐酸巴马汀的含量差异也不大,但盐酸药根碱、非洲防己碱、盐酸表小檗碱和盐酸小檗碱的含量却有较大差异。 结论 该方法具有分析速度快、灵敏度高、重现性好等特点,该方法的普及和应用将会为黄连花茶等系列深加工产品提供一个从原料到产品的质量控制方法。     

甜茶叶中甜茶苷的测定

采用高效液相色谱法测定广西甜茶中的主要甜味成分甜茶苷,色谱条件为:C18柱;甲醇-三氟乙酸溶液(体积比为75∶25)为流动相;流速1.0mL/min;检测波长208nm;柱温30℃;外标法定量。结果表明:在300mg/L~2000mg/L的范围内峰面积与质量浓度具有良好线性关系,得到以甜茶苷浓度为横坐标,峰面积为纵坐标建立线性回归方程Y=2176.24X-86.72,相关系数r为0.9991。该方法对甜茶原叶中甜茶苷的平均回收率(n=3)为103.9%。该方法快速简便,较为准确。以此方法对不同生长时期甜茶叶中的甜茶苷含量进行测定,考查了其中的变化规律。     

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.