顶空固相微萃取气—质联用分析香蕉的香气成分

采用顶空固相微萃取技术提取不同成熟阶段香蕉的香气成分,再经气质联用进行分析鉴定。着重研究3种极性不同的萃取头对香蕉香气成分萃取的影响,优化了分析条件,建立了稳定的萃取与气质联用分析测定的方法。研究结果表明,香蕉处于不同成熟阶段香气成分的种类和相对含量具有明显差异,在香蕉绿熟阶段分析测定适宜采用DVB/CAR/PDMS型萃取头,黄熟阶段采用PDMS型萃取头,过熟阶段采用CW/DVB型萃取头。

顶空固相微萃取分析落叶松刨花挥发性有机物

采用静态顶空—固相微萃取(HS-SPME)对落叶松刨花的挥发性有机物进行静态顶空吸附萃取,优化了萃取分析条件,即萃取温度80℃,萃取40min,吸附30min,脱附4min,并在优化条件下利用静态顶空—固相微萃取气质联用(HS-SPME-GC-MS)技术自动进样测定分析了刨花释放的组分。结果分析鉴定了9种组分,其中质量分数最高的组分为α-蒎烯(0.334),其次为β-水芹烯(0.130)、正己醛(0.113)、3-蒈烯(0.094)、2,6-二(1,1-二甲基乙基)-4-(1-甲基丙基)-苯酚(0.031)。优化的测试条件和原料的组分分析为后期落叶松刨花板的挥发性有机物释放研究提供了支撑数据。

晚香玉花香成分时空动态变化的研究

为了探讨晚香玉花香成分的时空动态变化,采用顶空—固相微萃取与气相色谱—质谱联用技术,对晚香玉单瓣和重瓣品种4个花期及单瓣品种花器官不同部位释放的香气成分进行了分析。结果表明,晚香玉不同花期的芳香成分种类和相对含量存在明显差异,单瓣品种花蕾期至盛开期分别检出芳香成分9、13、16和31种,随着花的不断发育,萜烯类化合物含量呈现高-低的变化趋势,醇类化合物含量呈现低-高-低的变化趋势,酚类化合物和酯类化合物含量均呈现低-高的变化趋势;重瓣品种花蕾期至盛开期分别检出芳香成分3、3、8和8种,随着开花的进程推进,萜烯类化合物和酚类化合物含量呈现低-高-低的变化趋势,酯类化合物含量呈现低-高的变化趋势,醇类化合物含量则呈现高-低-高的变化趋势。不同部位释放的香气成分种类和相对含量不同,从晚香玉单瓣品种花瓣、雌蕊、雄蕊中各检测出21、12和20种香气成分,且雌蕊主要释放萜烯类化合物,花瓣和雄蕊主要释放萜烯类和酚类化合物。本研究结果为进一步阐明花香化合物的分子调控机制奠定了基础。

不同贮藏时间的普洱茶香气成分分析

采用顶空—固相微萃取技术提取不同贮藏时间的普洱茶香气成分,经气质联用分析鉴定,结果表明,贮藏30年、25年、6年和当年生产的茶样中,萜烯化合物及其衍生物含量分别为51.42%、89.15%、74.10%、39.72%。但陈茶与新茶中的萜烯化合物及其衍生物的种类却有明显的不同,陈茶中以反-丁香烯为主,在贮藏30年、25年、6年茶样中的含量分别达36.78%、66.98%、56.08%,而当年生产的样品以愈创木烯为主,其含量达33.30%,反-丁香烯含量仅为1.02%。与当年生产的茶样相比,陈茶香气成分种类和含量都较少,贮藏30年、25年、6年茶样分别鉴定出23、24、22种香气化合物,而当年生产的茶样共鉴定出36种化合物。

HS—SPME/GC—MS分析无锡绿茶香气成分

采用顶空—固相微萃取—气质联用(HS—SPME/GC—MS)法分析无锡毫茶与太湖翠竹两种典型无锡绿茶的香气成分,分别检测出74和56种化合物,各占总峰面积的98.59%和98.51%。醇类、醛类、烷烃、酯类、羧酸和酮类化合物是主要成分,但在两个品种中的相对含量有较大差异。无锡毫茶中的醛类、酮类、羧酸类化合物含量均高于太湖翠竹,而醇类、酯类、烃类化合物含量均低于太湖翠竹。两个绿茶品种共有的香气成分有1-戊醇、叶醇、芳樟醇及其氧化物、水杨酸甲酯、己醛、刺柏烯等16种化合物,它们能提供清香、花香与果香,是无锡绿茶香气的主要贡献者。研究还表明,前处理采用HS—SPME法比同时蒸馏—萃取法能更真实体现茶叶原有的香气成分。

欧洲水仙4个花期香气成分的GC-MS分析

为了研究欧洲水仙花发育过程中香气成分的动态变化,以欧洲水仙‘荷兰船长’为材料,采用顶空—固相微萃取(HS-SPME)和气相色谱—质谱(GC-MS)联用技术分析其4个花期的香气成分及其含量的变化。结果表明:欧洲水仙花发育的不同时期,香气成分及含量差异明显。4个花期共鉴定出26种香气化合物,萜烯类化合物是其主要香气成分,其次是醇类化合物,主要的香气成分有(Z)-β-罗勒烯、别罗勒烯、β-月桂烯、对苯二甲醚、(E)-β-罗勒烯、桉叶油醇、萜品油烯、3-蒈烯、芳樟醇。欧洲水仙‘荷兰船长’主要的特征香气成分是(Z)-β-罗勒烯、β-月桂烯和别罗勒烯。主要香气成分的释放在整个开花期间呈现先升后降的趋势,种类数量和含量均在盛花期达到最高。

圈养大熊猫人工配合饲料的气味特点与香气成分研究

为了探寻大熊猫喜食人工配合饲料的气味特点和香气成分,用嗅感品评和顶空—固相微萃取—气质联用法对圈养大熊猫所食的人工配合饲料进行了气味特点、挥发性有机物及香气成分研究。结果表明:嗅感品评人工配合饲料的气味较强,愉悦度较好,香味较持久,含有焦糖样甜香味、熟玉米香气、豆粕样香气、谷物发酵香气、酸香气息、油脂气息及肉腥气息,其中甜香浓郁;顶空—固相微萃取—气质联用法共发现62种香气成分,归类为醛16种、醇15种、酮10种、杂环化合物6种、烯烃6种、羧酸4种、酚2种、醚1种、酯1种、芳烃1种,相对含量较高的单一香气成分是己醛、苯甲醛、1-辛烯-3-醇、1-己醇、2-戊基呋喃、2-呋喃甲醇、麦芽酚、苯乙烯、壬醛及庚醛,醛类、醇类及杂环类香气成分是人工配合饲料气味的主要贡献物质种类;与甜香味相关的香气成分数量多达16种,平均相对含量累计达23.75%。突出的焦糖样甜香味是人工配合饲料气味的主要特征。

圈养大熊猫乳汁香气成分探究

为了探寻圈养大熊猫乳汁香气的物质组成,用顶空—固相微萃取—气质联用法对4只圈养大熊猫母兽(6岁、9岁、12岁、14岁各1只)在仔兽10日龄、23日龄、56日龄时乳汁中的挥发性有机物质,通过不同型号的SPME头、不同的SPME温度和时长、不同的GC-MS联用仪、不同类型的毛细管柱、不同的程序升温进行了6次测试,共计发现46种香气成分,可归类为醇9种、酚3种、醛12种、酮7种、羧酸7种、酯1种、内酯2种、杂环化合物4种、芳香烃1种,主要香气成分为:己醛、2-丁酮、苯酚、3-甲基丁醛、己酸、戊醛、2-戊酮、2-甲基-3-丁烯-2-醇、1-辛烯-3-醇、3-己烯-1-醇,醛类是圈养大熊猫乳汁香气的重要贡献物质种类。

基于大熊猫择食机理的斑苦竹鲜叶和干叶气味及成分差异研究

为了进一步探索大熊猫择食的气味机理,选择不同性别、年龄和繁殖生理阶段的7只圈养大熊猫作为供试动物,用来自同株斑苦竹的新鲜竹叶和经2d或3d室内自然阴干的竹叶饲喂同一只大熊猫,观察大熊猫摄食竹叶的整个行为过程,并对竹叶样品进行嗅感品评和相关仪器分析。结果表明:受试大熊猫在嗅闻后均喜欢取食鲜叶,几乎不取食干叶;鲜叶和干叶的气味强度、愉悦度、透发性、青香、甜气、木质气、新鲜感、嫩感和多汁感均有极显著差异(P<0.01),且与竹叶水分含量之间存在极强的或正或负的线性相关关系;鲜叶与干叶之间整体气味信息的差异性,可通过PCA和LDA分析进行有效区分;鲜叶与干叶之间在挥发性有机物和典型香气成分上存在类别、种数和相对含量的不同;斑苦竹叶变干的过程是多种气味韵调及成分此消彼长的过程;斑苦竹鲜叶中突出的青香、明显的新鲜感和轻微的甜气等是诱导大熊猫取食的主要气味韵调,而干叶的新鲜感大量散失,青香和甜气大幅减弱,木质气大幅上升,导致干叶缺失了诱食性。

圈养大熊猫选择5种竹叶采食的气味机理初探

为了探索圈养大熊猫选择竹叶采食的气味机理,用毛竹、牛儿竹、硬头黄竹、清甜竹及孝顺竹5种新鲜竹子饲喂大熊猫,观察记录大熊猫在同时提供多种食物的条件下自由选择竹叶的采食行为,随机多点采集的竹叶样品通过嗅感品评、电子鼻测试和HSSPME-GC-MS分析以研究竹叶的气味特点和香气成分,结果表明,受试圈养大熊猫嗅闻5种供试竹叶后均有不同数量的采食,但采食毛竹叶存在个体差异,采食孝顺竹叶存在个体和季节性差异;这5种竹叶均有多种气味韵调,相同之处在于青香、叶香、草香、甜气、新鲜感和嫩气,不同之处在于这些气味韵调的相对强度或带有木质气息等其他微弱的气味;电子鼻测试结果证明了这5种竹叶间气味韵调的差异性,可通过PCA和LDA分析有效地区分;香气成分分析结果证实了这5种竹叶中多种气味形成的物质基础,醛类和醇类香气成分是这5种竹叶中香气及其强度的主要贡献物质类别;竹叶中突出的青香、轻微的甜气和新鲜感是诱导圈养大熊猫选择这5种竹叶采食的主要气味韵调。

用HS-SPME/GC-MS法分析3种不同类型山药的香气成分

为全面了解山药的香气挥发性成分以及不同类型山药的香气物质差别,应用顶空固相微萃取结合气相色谱─质谱联用技术对3种不同类型山药(白山药、野山药和紫山药)的挥发性成分进行了分析。结果表明:在3种山药中共有定性挥发性物质31种,其中醇类化合物最多,为18种。3个品种山药中的挥发性成分种类基本相同,但其主要挥发性成分和含量存在差异。苯甲醇在野山药中的含量低于在白山药和紫山药中的,而乙酸在野山药中的含量高于在白山药和紫山药中的。苯甲醇和苯甲醛可能是山药香气的主要贡献化合物。

Rapid and simultaneous determination of ten off-flavor compounds in water by headspace solid phase microextraction and gas chromatography-mass spectrometry

A simple and sensitive analytical procedure for the determination of multi-component compounds in water samples was developed and optimized using the headspace solid-phase microextraction(HSSPME) coupled with gas chromatography-mass spectrometry(GC-MS). Ten off-flavor compounds, including geosmin(GSM), 2-methylisoborneol(2-MIB), 2-isopropyl-3-methoxypyrazine(IPMP), 2-isobutyl-3-methoxypyrazine(IBMP), β-ionone, trans-2,cis-6-nonadienal(NDE), 2,3,4-trichloroanisole(2,3,4-TCA), 2,3,6-trichroloanisole(2,3,6-TCA), 2,4,6-trichloroanisole(2,4,6-TCA), and 2,4,6-tribromoanisole(2,4,6-TBA) were used as the target analytes. The optimization of extraction parameters including fibers types, extraction time, extraction temperature, stirring rate, sample volume, and ionic strength was carried out through the univariate approach. Ten off-flavor compounds were quantified within 50 min under the optimal conditions. Calibration curves with good linearity(r^2=0.990-0.998) were obtained in the range 1.0/2.0-100 ng/L, while the limits of detection for all compounds were lower than or close to the odor threshold concentration. Furthermore, the proposed method was applied to analyzing and determining the off-flavor compounds in real water samples from water-treatment plants.

Essential Oils Composition of Two Endemic Umbelliferae Herbs Growing Wild in Turkey

The present study was carried out to determine the essential oil composition of aerial parts of two endemic umbelliferae herbs （Malabaila lasiocarpa Boiss. and Stenotaenia macrocarpa Freyn ＆ Sint. ex Freyn） collected from Bingol （Turkey）, using headspace solid-phase microextraction method and gas chromatography （GC） interfaced with mass spectrometer analysis. Forty six and 43 compounds were identified for M. lasiocarpa and S. macrocarpa, respectively, representing 91.40% and 90.86% of their respective essential oils. Germacrene D （20.71%）,β-elemene （12.40%）, spathulenol （11.60%） and β-selinene （9.67%） were identified as the major compound of M. lasiocarpa. β-sesquiphellandrene （19.68%）, hexyl isobutyrate （12.65%） and octanal （9.53%） were found to be the major compounds ofS. macrocarpa. Essential oil composition ofM. lasiocarpa has been determined for the first time and the results have been discussed in view of chemotaxonomy, natural products and potential usefulness of these plants.

Identification of Essential Oil Composition of Four Picea Mill, （Pinaceae） Species from Canada

The aim of this study was to determine the volatile composition of essential oil of four Picea Mill. species （Piceapungens Engelm., Picea mariana （Mill.） Britton, Picea glauca （Moench） Voss., Picea rubens Sarg.） needles. The volatile components extracted from these four species needles were analyzed by using headspace solid phase microextraction （HS-SPME）/gas chromatography-mass spectrum （GC-MS） and 31, 34, 27 and 24 compounds were identified representing 91.77%, 92.70% 92.38% and 94.06% of the total oil, respectively. The major constituents were found to be bornylacetate （29.40%）, camphor （26.43%）, 13-myrcene （7.47%） and camphene （7.01%） in P. pungens; camphene （22.03%）, bornylacetate （21.64%）, α-pinene （16.62%） and borneol （7.79%） in P. mariana; bornylacetate （31.25%）, limonene （17.27%）, α-pinene （15.85%）; camphene （13.65%） in P. glauca and borneol （12.38%）, α-pinene （10.36%）, germacrene D （9.86%） and δ-cadinene （8.25%） in P. rubens. This study sought to detecte new phytochemical data on the Picea genus to help chemotaxonomy and usable of studied species.

Determination of Trihalomethanes in Water Samples Using Headspace Solid-Phase Microextraction Gas Chromatography

The chlorination process is one of the water treatment method used for the disinfection of water. The disinfection by products are trihalomethanes such as chloroform, dichloromethane, dibromochloromethane and bromoform. A headspace solid-phase microextraction method has been developed for determination oftrihalomethanes in water samples. The experimental parameters such as the stirring rate, extraction time, extraction temperature and desorption time were investigated. The linearity, detection limits and percentage recovery were evaluated. The optimum conditions were stirring rate 800 rpm/min, extraction time 6 min, extraction temperature 20 ~C, desorption time 2.5 min and desorption temperature 220 ~C. The detection limits were 0.01 ~g/L and the recoveries were in the range of 86-110 %, The proposed method was successfully applied to determination of THM4 in tap water samples. The THM4 contents were varied depending on the sample sites and the season. The total THM4 contents in cool, summer and rainy season were in the range of 27.58-41.89, 32.06-60.73 and 46.26-69.87 p.g/L, respectively. Confirmation of the detected compounds in water samples were performed by gas chromatograph-mass spectrometer. The mass spectra of the target compounds in water samples is in good agreement with trihalomethanes standard spectra.

Essential Oil Composition of Endemic Pimpinella tunceliana YiId. from Turkey for the First Time

The objective of this study was to examine the essential oil ofPimpinella tunceliana Yild. growing wild in the Eastern part of Turkey for the first time. Obtained results were discussed with the genus patterns and natural products. The essential oil of P. tunceliana was analyzed by head space-solid phase microextraction （HS-SPME）/gas chromatography-mass spectrometry （GC-MS） technique, and 50 compounds were identified, representing 96.3% of the oil. The main constituents of P. tunceliana were β-caryophyllene （13.9%）, β-bisabolene （10.4%）, anethole （9.3%）, sabinene （7.5%）, limonene （6.9%） and germacrene D （6.8%）. In this study, essential oil contents of P. tunceliana that is a new and endemic species was studied for the first time, and important results were presented in respect to the composition of the oil of this new species of Pimpinella.

Analysis of Aroma Volatile Profile of Philippine Durian Pulp （Durio zibethinus Rumph, ex Murray） Using HS-SPME Coupled with GC-MS

Durian （Durio zibethinus Rumph. ex Murray） is an exotic tropical fruit known for its excellent flavor and strong distinctive aroma. Volatiles of durian pulp from different cultivars in Thailand, Malaysia and Indonesia were already reported. However, no study of volatiles from Philippine ＂Puyat＂ durian is available. ＂Puyat＂ is the most preferred by consumers in the Philippines due to its firm flesh with sweet and buttery taste. Aroma volatile compounds were analyzed by headspace solid phase microextraction （HS-SPME） method and gas chromatography-mass spectrometry （GC-MS）. Volatiles were extracted for 1 h using 65 μm PDM/DVB SPME fiber and separated by DB-WAX capillary column （30 m × 0.25 mm id × 0.25 μm film thickness）. Durian pulp produced 22 volatiles composed of 15 esters, six sulfurs and one thioacetal. Ethyl propanoate, ethyl octanoate, propyl propanoate, ethyl 2-methyl butanoate and diethyl disulfide were the major compounds identified. These compounds were also reported to be the most abundant in durian cultivars of other countries. Results of this study can then be used for future development of postharvest technologies to control the production of volatiles from Philippine durian pulp.

Aroma changes of black tea prepared from methyl jasmonate treated tea plants

Methyl jasmonate（MeJA） was widely applied in promoting food quality.Aroma is one of the key indicators in judging the quality of tea.This study examined the effect of exogenous MeJA treatment on tea aroma.The aroma components in black tea prepared from MeJA-treated fresh tea leaves were extracted using headspace solid-phase microextraction（HS-SPME） and were analyzed using gas chromatography-mass spectrometry（GC-MS） and GC-olfactometry（GC-O）.Forty-five volatile compounds were identified.The results revealed that the MeJA-treated black tea had higher levels of terpene alcohols and hexenyl esters than the untreated tea.Moreover,several newly components,including copaene,cubenol,and indole,were induced by the MeJA treatment.The activities of polyphenol oxidase and β-glucosidase in fresh tea leaves changed after the MeJA treatment.Quantitative real-time polymerase chain reaction（qRT-PCR） analysis indicated that the gene expression levels of polyphenol oxidase and β-primeverosidase were upregulated by two and three folds,respectively,by the MeJA treatment（P0.01）; however,the gene expression of β-glucosidase was downregulated to a half level.In general,the aroma quality of the MeJAtreated black tea was clearly improved.

Butyltin compounds in vinegar collected in Beijing:Species distribution and source investigation

Forty-eight vinegar samples including white vinegar, rice vinegar and mature vinegar were collected from several markets in Beijing. Butyltin compounds were determined by headspace solid-phase microextraction coupled with gas chromatography and flame photometric detector after in situ ethylation with sodium tetraethylborate. Butyltin species were detected in sixteen vinegar samples and ranged from 0.012 to 14.10 lag Sn L 1. The detection rate of white vinegar is higher than that of rice vinegar and mature vinegar. Vinegar samples with relatively high butyltin concentration (〉1.5 μg Sn L-1) were those stored in plastic bags, indicating that the plastic bag was one of the possible sources of butyltin contamination. This was further confirmed by the leaching experiments of three selected plastic bags, and monobutyltin was detected in the leaching solvents. According to the estimation, the average daily intake of total butyltin compounds through vinegar consumption is about 0.04 ng Sn/kg b.w., much lower than the Tolerable Daily Intake (TDI) of 100 ng Sn/kg b.w. set by the European Food Safety Authority (EFSA).