22种不同来源信阳毛尖茶的分类比较

为了探究采制时节、产地、等级等因素对信阳毛尖茶品质成分的影响,本文采用高效液相色谱等方法对22个不同来源的信阳毛尖茶中儿茶素、黄酮类、酚酸类、嘌呤碱等品质成分进行测定。主成分分析、聚类分析和偏最小乘法-判别分析显示采制时节是影响信阳毛尖品质成分的主要因素,不同来源信阳毛尖基本可按照采制时节分为明前、雨前和春尾。单因素方差分析显示不同采制时节信阳毛尖茶在8种儿茶素、5种黄酮类、2种嘌呤碱以及没食子酸、游离氨基酸等品质成分上存在极显著差异(P<0.01):明前茶中的游离氨基酸总量和(+)-儿茶素(C)含量最高、而(+)-没食子儿茶素(GC)、(-)-表没食子儿茶素(EGC)、(-)-表儿茶素没食子酸酯(ECG)、(-)-表没食子儿茶素没食子酸酯(EGCG)、没食子酸、芦丁、杨梅素、槲皮素、可可碱含量最低,与雨前茶和春尾茶存在显著(P<0.05)或极显著差异(P<0.01)。不同产地和等级之间C、ECG、(-)-表没食子儿茶素(EGC)等儿茶素;芦丁、花旗松素、杨梅素等黄酮类;以及可可碱、茶碱等嘌呤碱含量存在显著(P<0.05)或极显著差异(P<0.01)。相对而言,四望山毛尖茶中非酯型儿茶素含量较高,而黄酮总量较低;芽头中游离氨基酸和C含量最高,而EGC和杨梅素含量最低,这对信阳毛尖采制时节的识别有一定影响。本文首次基于茶叶中品质成分对不同来源的信阳毛尖进行了分类比较,为明前茶的识别提供了科学依据。     

基于非靶向代谢组学的信阳毛尖茶加工过程非挥发物代谢轮廓分析

为了解信阳毛尖茶在加工过程中非挥发性代谢物的变化规律,以信阳群体种鲜叶为原料,采用非靶向代谢组学技术对信阳毛尖茶加工过程样品进行系统分析。结果显示,在信阳毛尖茶加工过程中共对比鉴定出1 000种非挥发性代谢物,多元统计分析表明信阳毛尖茶在杀青后其非挥发性代谢物发生显著变化;同时共筛选出53个差异化合物,其中氨基酸、儿茶素、黄酮糖苷、脂质、嘌呤核苷、有机酸等化合物的转化是形成信阳毛尖茶风味和品质的关键;尤其是一些酰化黄酮糖苷、溶血磷脂酰类、嘌呤核苷类化合物在杀青后相对含量显著提升;京都基因与基因组百科全书代谢通路富集分析结果显示,差异化合物在嘌呤代谢,甘油磷脂代谢,苯丙氨酸代谢,氨酰基-tRNA生物合成,苯丙氨酸、酪氨酸和色氨酸生物合成和甘氨酸、丝氨酸和苏氨酸代谢这些代谢通路中显著富集（P<0.05）。本研究进一步挖掘了影响信阳毛尖茶风味和品质的主要非挥发性代谢物,为揭示信阳毛尖茶风味和品质形成机制提供依据和参考。     

不同季节信阳毛尖茶主要生化成分及其矿质元素差异性分析

目的 基于不同季节信阳毛尖茶的生化成分和矿质元素,探究多元统计分析方法对不同季节信阳毛尖茶的有效区分。方法 采用高效液相色谱法等化学方法对64种信阳毛尖茶主要生化成分及其矿质元素进行检测分析,结合正交矫正偏最小二乘法判别分析获取不同季节茶样的组间差异。结果 研究结果表明游离氨基酸、黄酮类物质、水溶性碳水化合物、非酯型儿茶素、表儿茶素(epicatechin,EC)、表没食子儿茶素(epigallocatechin,EGC)、没食子酸(gallic acid,GA)及矿质元素均存在季节性显著差异。判别分析可将信阳毛尖春茶和夏秋茶明显区分,并鉴定出黄酮类物质、游离氨基酸、GA、儿茶素(catechin,C)、EC、EGC、Mg和Zn 8种判别不同季节信阳毛尖茶的重要差异化合物。热图分析结果进一步证实,茶多酚、游离氨基酸、C、表儿茶素没食子酸酯(epicatechin gallate,ECG)和GA等物质主要在春茶中积累,黄酮类物质、EGC、表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)、Mg、Fe、Zn和Se等物质主要在夏秋茶上积累。结论 本研究鉴别了不同季节信阳毛尖茶的特征性差异化合物,为信阳毛尖茶的季节识别提供理论基础。     

顶空固相微萃取-气相色谱-质谱法对比分析毛火温度对信阳毛尖茶香气成分的影响

摘 要：目的 研究分析毛火温度对信阳毛尖茶品质影响。方法 选取不同品种、干燥毛火温度的信阳毛尖茶,并采用顶空固相微萃取-气相色谱-质谱法(headspace-solid phase microextraction-gas chromatography-mass spectrometry, HS-SPME-GC-MS)对供试样香气物质进行分析。结果 醛类、醇类、酯类、酮类、酸类、芳香烃以及碳氢、杂氧化合物是信阳毛尖茶的主要香气化合物种类。140℃毛火烘焙乌牛早信阳毛尖茶供试样中芳樟醇、柠檬烯、γ-松油烯、肉桂烯与反式芳樟醇氧化物(呋喃)等均最高。110℃毛火烘焙乌牛早信阳毛尖茶供试样中β-环柠檬醛与顺式芳樟醇氧化物(呋喃)含量最高。140℃毛火烘焙信阳毛尖茶供试样的茶多酚、表没食子儿茶素没食子酸酯( epigallocatechin gallate, EGCG )、没食子酸( gallic acid, GA )、儿茶素( catechins, C)的含量均低于110℃毛火烘焙信阳毛尖茶供试样。结论 在信阳毛尖茶加工中,适当提高毛火温度,可提升茶叶香气,降低滋味苦涩感。     

基于代谢组学研究不同花色种类云南白茶的化学成分差异

以云白毫、白牡丹（包括月光白一级和月光白二级）、云寿为云南白茶的代表性样品,采用基于超高效液相色谱-四极杆轨道阱质谱的代谢组学方法对不同花色种类云南白茶的化学成分差异进行研究。共鉴定出120 个化合物,包括儿茶素类、二聚儿茶素类、氨基酸类、生物碱类、酚酸类、有机酸类、香气糖苷类、N-乙基-2-吡咯烷酮取代的儿茶素类、黄酮糖苷类、脂质类等。偏最小二乘法判别分析和热图分析分别表明不同花色种类云南白茶的化学成分存在较大差异,共得到76 个化合物具有组间显著性差异（P＜0.05）,其中儿茶素类、二聚儿茶素类、生物碱类、酚酸类、茶氨酸等化合物随云南白茶原料嫩度的降低,含量下降;部分氨基酸和杨梅素苷在白牡丹中含量相对较高;芹菜素苷、山柰酚苷、槲皮素苷、脂质类化合物在云寿中含量相对较高。本研究可为云南白茶感官品质和营养价值的研究以及等级判别提供理论依据。     

基于非靶向代谢组学的白茶与绿茶、乌龙茶和红茶代谢产物特征比较

探究白茶的代谢物特征及其形成的加工学原理,以福云六号和黄旦茶树品种一芽二三叶鲜叶为原料,按照白茶、绿茶、乌龙茶和红茶加工方法制成相应茶类。使用超高效液相色谱-四极杆飞行时间质谱测定鲜叶样品和不同茶类中全部代谢物丰度,并对代谢物进行筛选和鉴定。结果表明,2个品种制成的不同茶类之间代谢差异物共筛选出152个和148个,其中33个茶叶中主要物质得到鉴定,这些物质属于儿茶素及其衍生物类、花青素类、水解单宁类、黄酮醇或黄酮糖苷类、酚酸类和茶黄素类。主成分分析表明白茶在第1主成分上介于乌龙茶和红茶之间,在第2主成分上区别于其他茶类。载荷图显示黄酮醇或黄酮糖苷类物质、酯型儿茶素和儿茶素衍生物是白茶区别于其他茶类的特征代谢产物。从物质丰度上看,白茶中大部分黄酮醇或黄酮糖苷类物质显著高于其他茶类;儿茶素和花青素显著低于绿茶并接近红茶,特别是非酯型儿茶素;茶黄素和茶黄素-3-没食子酸酯高于绿茶,但茶黄素-3’-没食子酸酯和茶黄素-3,3’-没食子酸酯与绿茶相比无显著差异;儿茶素衍生物8-C-抗坏血酸基-表没食子儿茶素没食子酸酯显著高于其他茶类。     

不同年份湖北青砖的特征性成分分析

为探明不同年份湖北青砖品质成分的变化规律,筛选特征性成分,采用高效液相色谱和全自动氨基酸分析仪等对15个供试青砖的主要品质成分进行检测,结合多元统计方法和热图对青砖茶的特征性成分进行筛选和样品的聚类。结果表明,随贮藏时间的延长,黄酮及黄酮醇类(杨梅素、槲皮素、山奈酚)、茶褐素、没食子酸、水杨酸、琥珀酸的含量呈增加趋势,而茶多酚、儿茶素类(表儿茶素和表没食子儿茶素没食子酸酯)、游离氨基酸单体(茶氨酸、丙氨酸、半胱氨酸、亮氨酸、苯丙氨酸、赖氨酸和组氨酸)的含量呈下降趋势;主成分分析筛选出黄酮、杨梅素、水杨酸、茶褐素、茶氨酸、茶多酚等10种特征性成分;系统聚类分析和热图结果表明湖北青砖的品质转化始于贮藏7年时,贮藏9年时差异明显,影响年份聚类的关键品质成分为茶多酚、茶褐素和黄酮。     

茶叶提取物体外抗氧化活性与其功能性成分含量的相关性研究

分别选取信阳毛尖、红碎茶、普洱熟茶为典型不发酵、全发酵及后发酵茶种,测定其醇提物及水提物中的主要成分,并以氧自由基的吸收能力(ORAC)和DPPH自由基的清除能力为指标,比较各样品体外抗氧化活性,采用功能化合物重组模型,探究茶叶提取物抗氧化活性的主要贡献物质。结果表明:茶叶醇提物中茶多酚、咖啡因及醇溶蛋白的含量较高,其ORAC值及DPPH自由基清除能力均较对应水提物强;茶叶水提物功能性组分以茶多酚、茶多糖及氨基酸为主,都具有一定的抗氧化活性。其中茶多酚含量,尤其是酯型儿茶素(ECG和EGCG)含量是影响茶叶提取物抗氧化活性的主要因素。重组试验结果表明,儿茶素和没食子酸是不发酵茶(信阳毛尖)提取物的主要抗氧化组分,但并不是红碎茶、普洱熟茶等发酵茶中的主要抗氧化成分。     

不同采制季节信阳白茶品质成分的比较分析

该研究采用高效液相色谱法（HPLC）等方法对春季、夏季和秋季茶树鲜叶加工而成的18款信阳白茶茶样中的8种儿茶素、6种黄酮类、2种酚酸、3种嘌呤碱等品质成分进行测定,对不同采制季节的信阳白茶进行品质成分进行对比分析。主成分分析（PCA）和聚类分析（HCA）技术均能将信阳白茶茶样按照采制季节不同进行归类,分为春季、夏季和秋季白茶。通过独立样本t-检验和单因素方差分析,探究了不同采制季节信阳白茶中儿茶素、黄酮类、嘌呤碱等品质成分差异。结果显示：不同采制季节信阳白茶中的品质成分均存在显著性（p<0.01）或极显著性（p<0.001）差异;春季白茶中(-)-表没食子酸儿茶素（EGC）、(-)-表没食子儿茶素没食子酸酯（EGCG）和鞣花酸含量极显著性（p<0.001）高于夏季或秋季白茶,含量分别为33.26、59.30、2.81 mg/g左右;夏季白茶中(-)-儿茶素没食子酸酯（CG）、(-)-没食子儿茶素没食子酸酯（GCG）、花旗松素、芦丁、杨梅素、山奈酚、槲皮素、木犀草素含量极显著性（p<0.001）高于秋季白茶,含量分别高达0.72、4.40、0.84、2.40、0.97、0.21、0.25、0.11 mg/g;秋季白茶中(+)-儿茶素（C）、(-)-表儿茶素（EC）、(-)-表儿茶素没食子酸酯（ECG）、没食子酸、咖啡碱和可可碱极显著性（p<0.001）高于夏季或春季白茶,含量分别为4.98、14.35、27.02、10.10、36.85、1.53 mg/g。该研究揭示了信阳白茶的品质特征和不同采制季节信阳白茶品质成分差异,为白茶等茶叶采制季节的识别提供了科学依据。     

3个不同产地白茶品质成分与体外抗氧化能力比较

采用高效液相色谱（high performance liquid chromatography,HPLC）等方法对3个不同来源18份白茶茶样中8种儿茶素、6种黄酮类、2种酚酸、1种水解单宁、3种嘌呤碱等成分进行测定,并检测白茶的铁离子还原抗氧化能力、DPPH自由基清除能力、ABTS+自由基清除能力、羟基自由基清除能力和超氧阴离子自由基清除能力。主成分分析（principal component analysis,PCA）将白茶分为信阳白茶、福鼎白茶和云南白茶3组,表明产地对白茶品质成分有重要影响。热图分析和单因素方差分析揭示了不同产地白茶中儿茶素、黄酮类、没食子酸和嘌呤碱等品质成分存在差异。由于茶树鲜叶原料差异,云南白茶中（+）-儿茶素、（-）-表儿茶素、（-）-表没食子酸儿茶素、（-）-表儿茶素没食子酸酯、（-）-没食子儿茶素没食子酸酯、芦丁、咖啡碱和可可碱含量均极显著（p<0.01）高于福鼎白茶或信阳白茶,含量分别为4.82、16.46、36.30、29.69、4.95、3.18、42.97、1.79 mg/g。福鼎白茶中游离氨基酸、可溶性糖、（+）-没食子儿茶素、（-）-儿...     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the