We have investigated the use of flash evaporation, headspace solid-phase microextraction (HS-SPME) and steam distillation (SD) as sample concentration and preparation techniques for the analysis of volatile constituen...We have investigated the use of flash evaporation, headspace solid-phase microextraction (HS-SPME) and steam distillation (SD) as sample concentration and preparation techniques for the analysis of volatile constituents present in Houttuynia cordata Thunb. The samples were analyzed by gas chromatography (GC) and identified by mass spectrometry (MS). Comparison studies were performed. It was found that the results obtained between Headspace solid-phase microextraction HS-SPME and SD techniques were in good agreement. Seventy-nine compounds in Houttuynia cordata Thunb were identified by MS. In flash evaporation, thirty-nine compounds were identified. Discrimination in the response for many constituents studied was not observed, which can be clearly observed in SD and HS-SPME techniques. As a conclusion, HS-SPME is a powerful tool for determining the volatile constitutes present in the Houttuynia cordata.展开更多
In this report, gas chromatography-mass spectrometry (GC-MS) based non-targeted metabolomics is used to develop appropriate headspace solid phase microextractions (HS-SPME) to enhance the understanding of volatile com...In this report, gas chromatography-mass spectrometry (GC-MS) based non-targeted metabolomics is used to develop appropriate headspace solid phase microextractions (HS-SPME) to enhance the understanding of volatile complexity of flue-cured tobacco leaves. Non-targeted metabolic profiling of GC-MS shows that the extraction condition of HS-SPME at 100?C for 30 min provides a better metabolite profile than other extraction conditions tested. GC-MS and principal component analyses (PCA) show that among five types of fibers tested, 100 μm polydimethylsiloxane (PMDS), 65 μm polydimethylsiloxane/divinylbenzene (PMDS/DVB) and 75 μm carboxen/polydimethylsiloxane (CAR/ PMS) provide a better reproducible metabolite profile. Based on an appropriate PDMS extraction condition optimized, we use GC-MS analysis and PCA to compare metabolite profiles in flue-cured leaves of tobacco plants grown in North Carolina, India and Brazil, respectively. The resulting data of PCA show that the global metabolic profiles in North Carolina samples are separated from those in Brazil and India samples, two groups of which are characterized by a partially overlapped pattern. Several peaks that were differentially accumulated in samples were annotated to known metabolites by deconvolution analysis, such as norsolanadione, solavetivone and rishtin. Norsolanadione is detected only in Brazil samples. Solavetivone is detected in samples of India and Brazil but not in those of North Carolina. Rishtin is detected in samples of North Carolina and India but not in Brazil samples. These data indicate that not only can a non-targeted metabolic profiling approach enhance the understanding of volatile complexity, but also can identify marker volatile metabolites in tobacco leaves produced in different growth regions.展开更多
采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry...采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry,GC×GC-TOF-MS)以及香气活度值(odour active value,OAV),对红星二锅头白酒的挥发性成分进行全面解析。研究发现,HS-SPME、LLE分别定性出928、802种挥发性化合物,共计定性出1304种挥发性化合物,共同定性出426种挥发性化合物。基于HS-SPME数据,通过香气数据库筛选出具有香气特征的382种香气化合物,其中酯类相对百分含量占比最高,其次是醇类、酸类和醛类。计算得到了49种香气化合物OAV>1,其中酯类(辛酸乙酯、异戊酸乙酯等)和萜烯类(β-大马酮)对白酒风味的贡献最大,醛类(异戊醛、己醛等)和含硫类(二甲基三硫)其次,醇类(1-辛烯-3-醇)和含氮类(2,3,5-三甲基吡嗪)也有一定风味贡献。该研究丰富了红星二锅头白酒的风味研究,也为下一步生产研究及调控提供了理论和数据支撑。展开更多
目的:研究不同干燥方式对大红袍果皮香气成分的影响及差异情况。方法:采用顶空固相微萃取结合气相色谱-质谱联用技术(headspace solid phase microextraction and gas chromatography-mass spectrometry,HSSPME-GC-MS)分析5种干燥方式(...目的:研究不同干燥方式对大红袍果皮香气成分的影响及差异情况。方法:采用顶空固相微萃取结合气相色谱-质谱联用技术(headspace solid phase microextraction and gas chromatography-mass spectrometry,HSSPME-GC-MS)分析5种干燥方式(热风干燥、真空干燥、室内恒温干燥、微波干燥和自然晾晒)处理后大红袍果皮中香气成分的种类和相对含量,经正交偏最小二乘判别分析(OPLS-DA),筛选出变量重要性投影(VIP)值≥1的差异香气成分。结果:大红袍果皮中共检出香气成分94个,其中烯烃类20个、酯类20个,醇类16个,醛类9个,酸类7个,酮类5个,酚类3个,以及其他种类(包括醚类、芳香类等)14个,有36个共有成分,58个特异性成分,含量最高的是D-柠檬烯(41.30%±1.45%)。所建立OPLS-DA模型稳定可靠,通过VIP法筛选出28个差异香气成分,通过相对气味活度值(ROAV)分析,确定了4个关键香气成分,分别为D-柠檬烯、芳樟醇、二氢猕猴桃内酯和反式橙花叔醇,其中,D-柠檬烯香气贡献最大。结论:本研究利用HS-SPME-GC-MS技术分析5种干燥方式下大红袍果皮香气成分,OPLS-DA模型和聚类分析能较好地区分不同干燥方式的大红袍果皮。筛选出来28个差异香气成分及4个关键香气成分。其中,采用微波干燥的大红袍果皮关键香气成分相对含量最高,热风干燥次之。本研究为大红袍果皮干燥方式选择及药食同源资源开发提供参考。展开更多
为探明创新型联合杀青方式对绿茶栗香形成的影响,以滚筒杀青为对照,设定滚筒-微波、滚筒-远红外、滚筒-微波-远红外、滚筒-远红外-微波联合杀青,共5种方式,结合感官审评,通过气相色谱-质谱检测成品茶样香气成分68种,采用偏最小二乘-判...为探明创新型联合杀青方式对绿茶栗香形成的影响,以滚筒杀青为对照,设定滚筒-微波、滚筒-远红外、滚筒-微波-远红外、滚筒-远红外-微波联合杀青,共5种方式,结合感官审评,通过气相色谱-质谱检测成品茶样香气成分68种,采用偏最小二乘-判别分析(partial least squares-discriminant analysis,PLS-DA)、层次聚类分析、香气活度值法、差异显著性分析等探明绿茶栗香形成的最佳杀青方式,寻找栗香关键组分。结果表明,滚筒联合远红外有利于栗香品质的提升,其中以滚筒-远红外-微波联合杀青可获得高扬持久的栗香,且滋味鲜爽,整体品质最优;滚筒联合远红外杀青处理利于高沸点醇类、酮类、芳香烃类如芳樟醇、反式-β-紫罗酮等的转化与形成,以滚筒-远红外-微波处理含量显著最高;PLS-DA及层次聚类分析可根据栗香强度将不同类杀青方式准确区分及聚类,结合香气活度值,明确反式-β-紫罗酮、芳樟醇、顺-3-己酸己烯酯、壬醛、香叶醇、苯乙醛6种物质为栗香关键组分。本研究可为定向化、标准化生产优质栗香绿茶提供理论基础和技术指导。展开更多
文摘We have investigated the use of flash evaporation, headspace solid-phase microextraction (HS-SPME) and steam distillation (SD) as sample concentration and preparation techniques for the analysis of volatile constituents present in Houttuynia cordata Thunb. The samples were analyzed by gas chromatography (GC) and identified by mass spectrometry (MS). Comparison studies were performed. It was found that the results obtained between Headspace solid-phase microextraction HS-SPME and SD techniques were in good agreement. Seventy-nine compounds in Houttuynia cordata Thunb were identified by MS. In flash evaporation, thirty-nine compounds were identified. Discrimination in the response for many constituents studied was not observed, which can be clearly observed in SD and HS-SPME techniques. As a conclusion, HS-SPME is a powerful tool for determining the volatile constitutes present in the Houttuynia cordata.
文摘In this report, gas chromatography-mass spectrometry (GC-MS) based non-targeted metabolomics is used to develop appropriate headspace solid phase microextractions (HS-SPME) to enhance the understanding of volatile complexity of flue-cured tobacco leaves. Non-targeted metabolic profiling of GC-MS shows that the extraction condition of HS-SPME at 100?C for 30 min provides a better metabolite profile than other extraction conditions tested. GC-MS and principal component analyses (PCA) show that among five types of fibers tested, 100 μm polydimethylsiloxane (PMDS), 65 μm polydimethylsiloxane/divinylbenzene (PMDS/DVB) and 75 μm carboxen/polydimethylsiloxane (CAR/ PMS) provide a better reproducible metabolite profile. Based on an appropriate PDMS extraction condition optimized, we use GC-MS analysis and PCA to compare metabolite profiles in flue-cured leaves of tobacco plants grown in North Carolina, India and Brazil, respectively. The resulting data of PCA show that the global metabolic profiles in North Carolina samples are separated from those in Brazil and India samples, two groups of which are characterized by a partially overlapped pattern. Several peaks that were differentially accumulated in samples were annotated to known metabolites by deconvolution analysis, such as norsolanadione, solavetivone and rishtin. Norsolanadione is detected only in Brazil samples. Solavetivone is detected in samples of India and Brazil but not in those of North Carolina. Rishtin is detected in samples of North Carolina and India but not in Brazil samples. These data indicate that not only can a non-targeted metabolic profiling approach enhance the understanding of volatile complexity, but also can identify marker volatile metabolites in tobacco leaves produced in different growth regions.
文摘采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)和液液萃取(liquid-liquid extraction,LLE)结合全二维气相色谱飞行时间质谱(comprehensive two-dimensional gas chromatography time of flight mass spectrometry,GC×GC-TOF-MS)以及香气活度值(odour active value,OAV),对红星二锅头白酒的挥发性成分进行全面解析。研究发现,HS-SPME、LLE分别定性出928、802种挥发性化合物,共计定性出1304种挥发性化合物,共同定性出426种挥发性化合物。基于HS-SPME数据,通过香气数据库筛选出具有香气特征的382种香气化合物,其中酯类相对百分含量占比最高,其次是醇类、酸类和醛类。计算得到了49种香气化合物OAV>1,其中酯类(辛酸乙酯、异戊酸乙酯等)和萜烯类(β-大马酮)对白酒风味的贡献最大,醛类(异戊醛、己醛等)和含硫类(二甲基三硫)其次,醇类(1-辛烯-3-醇)和含氮类(2,3,5-三甲基吡嗪)也有一定风味贡献。该研究丰富了红星二锅头白酒的风味研究,也为下一步生产研究及调控提供了理论和数据支撑。
文摘目的:研究不同干燥方式对大红袍果皮香气成分的影响及差异情况。方法:采用顶空固相微萃取结合气相色谱-质谱联用技术(headspace solid phase microextraction and gas chromatography-mass spectrometry,HSSPME-GC-MS)分析5种干燥方式(热风干燥、真空干燥、室内恒温干燥、微波干燥和自然晾晒)处理后大红袍果皮中香气成分的种类和相对含量,经正交偏最小二乘判别分析(OPLS-DA),筛选出变量重要性投影(VIP)值≥1的差异香气成分。结果:大红袍果皮中共检出香气成分94个,其中烯烃类20个、酯类20个,醇类16个,醛类9个,酸类7个,酮类5个,酚类3个,以及其他种类(包括醚类、芳香类等)14个,有36个共有成分,58个特异性成分,含量最高的是D-柠檬烯(41.30%±1.45%)。所建立OPLS-DA模型稳定可靠,通过VIP法筛选出28个差异香气成分,通过相对气味活度值(ROAV)分析,确定了4个关键香气成分,分别为D-柠檬烯、芳樟醇、二氢猕猴桃内酯和反式橙花叔醇,其中,D-柠檬烯香气贡献最大。结论:本研究利用HS-SPME-GC-MS技术分析5种干燥方式下大红袍果皮香气成分,OPLS-DA模型和聚类分析能较好地区分不同干燥方式的大红袍果皮。筛选出来28个差异香气成分及4个关键香气成分。其中,采用微波干燥的大红袍果皮关键香气成分相对含量最高,热风干燥次之。本研究为大红袍果皮干燥方式选择及药食同源资源开发提供参考。
文摘为探明创新型联合杀青方式对绿茶栗香形成的影响,以滚筒杀青为对照,设定滚筒-微波、滚筒-远红外、滚筒-微波-远红外、滚筒-远红外-微波联合杀青,共5种方式,结合感官审评,通过气相色谱-质谱检测成品茶样香气成分68种,采用偏最小二乘-判别分析(partial least squares-discriminant analysis,PLS-DA)、层次聚类分析、香气活度值法、差异显著性分析等探明绿茶栗香形成的最佳杀青方式,寻找栗香关键组分。结果表明,滚筒联合远红外有利于栗香品质的提升,其中以滚筒-远红外-微波联合杀青可获得高扬持久的栗香,且滋味鲜爽,整体品质最优;滚筒联合远红外杀青处理利于高沸点醇类、酮类、芳香烃类如芳樟醇、反式-β-紫罗酮等的转化与形成,以滚筒-远红外-微波处理含量显著最高;PLS-DA及层次聚类分析可根据栗香强度将不同类杀青方式准确区分及聚类,结合香气活度值,明确反式-β-紫罗酮、芳樟醇、顺-3-己酸己烯酯、壬醛、香叶醇、苯乙醛6种物质为栗香关键组分。本研究可为定向化、标准化生产优质栗香绿茶提供理论基础和技术指导。
