A procedure for the sensory analysis of gas chromatographic effluents

A method is presented for determining those volatile components of foods that have flavour significance. The method leads to quantitative flavour specifications called charm that can be displayed graphically. The procedure is based upon the relative odour detection thresholds of volatile compounds of known gas chromatographic retention indices.     

Feature Selection and Recognition from Nonspecific Volatile Profiles for Discrimination of Apple Juices According to Variety and Geographical Origin

Abstract: Apple juice is a complex mixture of volatile and nonvolatile components. To develop discrimination models on the basis of the volatile composition for an efficient classification of apple juices according to apple variety and geographical origin, chromatography volatile profiles of 50 apple juice samples belonging to 6 varieties and from 5 counties of Shaanxi (China) were obtained by headspace solid‐phase microextraction coupled with gas chromatography. The volatile profiles were processed as continuous and nonspecific signals through multivariate analysis techniques. Different preprocessing methods were applied to raw chromatographic data. The blind chemometric analysis of the preprocessed chromatographic profiles was carried out. Stepwise linear discriminant analysis (SLDA) revealed satisfactory discriminations of apple juices according to variety and geographical origin, provided respectively 100% and 89.8% success rate in terms of prediction ability. Finally, the discriminant volatile compounds selected by SLDA were identified by gas chromatography‐mass spectrometry. The proposed strategy was able to verify the variety and geographical origin of apple juices involving only a reduced number of discriminate retention times selected by the stepwise procedure. This result encourages the similar procedures to be considered in quality control of apple juices. Practical Application: This work presented a method for an efficient discrimination of apple juices according to apple variety and geographical origin using HS‐SPME‐GC‐MS together with chemometric tools. Discrimination models developed could help to achieve greater control over the quality of the juice and to detect possible adulteration of the product.     

Solid Phase Microextraction for Cheese Volatile Compound Analysis

Cheese headspace volatile compounds were extracted with solid-phase microextraction (SPME) fibers, coated with either polydimethylsiloxane or polyacrylate, and thermally desorbed in the injector port for gas chromatographic (GC) analysis. Results with polyacrylate-coated fibers were better than those with a polydimethylsiloxane fiber. Major cheese volatile components such as volatile fatty acids and 5-lactones were readily extracted by both SPME fibers, but minor components such as volatile sulfur compounds were not observed. SPME-GC patterns were distinctly different among cheese varieties, and characteristic volatile compounds could be identified using multivariate techniques.     

IDENTIFICATION OF VOLATILE DATE COMPONENTS AND USE OF MULTIVARIATE ANALYSIS TO DISTINGUISH DATE VARIETIES1

Pentane extracts which possessed strong date-like aromas were obtained from three date varieties and analyzed by gas chromatography-mass spectrometry. Thirty-six volatile components were identified and only six of these had been found earlier in dates. Many of these components possessed aromas and flavors which could contribute to the sensory characteristics of dates, suggesting that a combination of volatile components is responsible for the desirable flavor of dates. Headspace gas chromatographic analysis of fresh dates from each of the three varieties combined with multivariate analysis involving eleven of the known constituents was used to distinguish differences among the varieties.     

HS-SPME-GC-MS分析新疆胡麻油挥发性成分的技术优化

采用顶空固相微萃取-气相色谱-质谱(headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS)联用技术对新疆胡麻油挥发性成分测定分析进行优化,以期获得HS-SPME-GCMS分析胡麻油挥发性香气的最佳条件。结果表明,采用DVB/CAR/PDMS萃取头,在磁力搅拌条件下,胡麻油SPME最佳萃取条件为萃取温度50℃、萃取时间40 min、解吸时间4 min,在该条件下采用HS-SPME-GC-MS鉴定出的胡麻油挥发性物质达到46种,主要包括醛类、酮类、醇类、酸类、酯类、烷烃类、杂环类及其他类物质,其中醛类、杂环类和醇类总相对含量较高,分别为30.14%、12.73%和9.25%,分离鉴定效果较好。     

Analysis of volatile components of fruits by HS‐PTV‐GC

A method for the analysis of fruit headspace using a programmed temperature vaporiser (PTV) gas chromatographic injector as an intermediate trap is proposed. The method consists of a purge of the volatile compounds into the PTV glass‐liner filled with a packing material of high surface area. The trapped compounds are thermally desorbed in the PTV injector and transferred to the gas chromatographic column. The variables that influence the extraction and transfer processes have been optimised for fruit flavour analysis. Examples of the application of the method to the analysis of bananas, blackberries and raspberries are given. © 1999 Society of Chemical Industry     

气相色谱-质谱法测定卵叶娃儿藤超临界CO2流体萃取物中挥发性成分

采用超临界CO2(SFE)从卵叶娃儿藤中萃取有效成分,萃取条件为:萃取釜压力35MPa,温度50℃,萃取时间3h,夹带剂95%乙醇用量20ml。采用气相色谱-质谱法对其挥发性成分进行鉴定,用归一化法测定各组分的含量。色谱条件:HP-5MS石英毛细管柱(0.25mm×30m×0.25μm),柱温60℃,恒温1min,以4℃/min升至280℃,保持10min;分流进样,分流比20:1。进样口温度250℃。在采用超临界CO2萃取法提取的卵叶娃儿藤提取物中共检出37种成分。     

香菇干燥过程中的挥发性成分的研究

本实验采用固相微萃取技术萃取热风干燥不同时段的香菇中的挥发性成分,然后用色谱-质谱联用分析鉴定,用GC-MS总离子流色谱峰面积分析其风味成分。香菇的挥发性成分主要是一些含硫和八碳的化合物。其中二甲基二硫醚、二甲基三硫醚、甲硫基二甲基三硫醚、1,2,4-三硫杂环戊烷、香菇精是香菇的特征风味成分。其中以含硫的杂环化合物最为重要,它们是香菇风味最重要的组成部分。     

Changes in flavour compound profiles of precooked pork after reheating (warmed-over flavour) using gas chromatography–olfactometry–mass spectrometry with chromatographic feature extraction

The unclear components and complex evaluation indicators affect the effectiveness of inhibition methods for warmed-over flavour (WOF). To evaluate the main components of WOF, the changes in flavour compound profiles of precooked pork after reheating were investigated quantitatively by using gas chromatography–olfactometry–mass spectrometry with chromatographic feature extraction. A total of 49 volatile compounds were identified, including 22 aroma-active compounds that were primarily derived from lipid oxidation. Fifteen key volatile compounds were obtained that represented principal components of the changes in flavour compound profiles, of which 1-octen-3-ol, (Z)-2-octenal and (E,E)-2,4-decadienal made the greatest contribution to the principal components and achieved odour activity value (OAVs) >1.0 after reheating. The results showed that the three compounds are the dominant volatile compounds and potential evaluation indicators of WOF. This study provides a further understanding of the components of WOF in precooked pork and an effective analysis method of gas chromatography.     

Determination of fatty acids in butter fat using temperature-programmed gas chromatography of the butyl esters

Substituting n-butanol for the methanol specified in the AOAC Official methods of analysis (sections 28.056–28.059) yields the butyl esters of the fatty acids with complete recovery of the volatile short-chain acids. Fatty acid butyrates can be determined using a continuous multistage temperature-programmed gas chromatographic method, with a 10% apolar 10C column. The results of the analysis in 1982, of fifty butters were compared with those of thirty butters analyzed in 1974. There were no practical significant differences in the fatty acid compositions of the 1974 and 1982 butters. A urea fractionation technique was used to concentrate minor components for identification and estimation.     

Gas chromatographic investigation of volatile nitrogen containing bases of Antarctic krill Euphausia superba Dana

The composition of the volatile nitrogen-containing bases of fresh-caught Antarctic krill E. superba has been investigated by gas chromatography. The analysis was carried out on three packed columns with Apiezon L, Triton X-305, PEG-1000 and one glass capillary column with Triton X-305. The components were identified by standardless gas chromatographic method with a special computer program. No less than 63 compounds have been found and 54 compounds have been identified, among these primary, secondary and tertiary aliphatic amines as well as heterocyclic bases. The presence of 5 compounds has been confirmed by GC/MS technique. Analysis with the help of a specific flame-photometric detector has shown the presence of 9 bi-functional nitrogen- and sulfur-containing compounds.     

Volatile Flavor Components from Boiled Crayfish (Procambarus clarkii) Tail Meat

The volatile flavor components of boiled red swamp crayfish (Procambarus clarkii) tail meat were characterized by a combination of dynamic headspace concentration on a porous polymer trap, high resolution gas chromatography, mass spectrometry and chromatography-coupled aroma sniffing evaluation. A total of 70 volatile compounds in many different chemical classes were identified and reported for the first time in crayfish tail meat. Various components gave green grassy, woody, buttery, metallic, or sulfur-like aroma characteristics. Most of the sensory characteristics of the individual components in the aromagram agreed well with the identification of the chemical structures eluted within the corresponding chromatographic period. However, several pleasant nutty, meaty and salty-meaty areas in the gas chromatographic aromagram remained unidentified.     

超声辅助溶剂萃取结合气相色谱-质谱法分析自热食品聚丙烯包装中挥发性成分

对超声辅助溶剂萃取法的萃取时间进行优化;在最佳萃取条件下,建立超声萃取结合气相色谱-质谱测定3 种自热食品聚丙烯包装的挥发性成分的方法;对比正己烷、乙醇、乙酸乙酯和二氯甲烷4 种溶剂的萃取效果,通过MS-DIAL解卷积、NIST谱库检索结合色谱保留指数对检出物质定性,利用毒理学关注阈值法确定其Cramer分类等级,并计算相对气味活度值分析潜在气味物质。结果表明：正己烷、乙酸乙酯、二氯甲烷的萃取效果相近,均对烃类物质有较好的提取效果;而乙醇对酯类物质的提取效果较好。3 种自热食品聚丙烯包装样品中共检测出72 种挥发性成分,其中N-(2-乙氨基)-1,3-丙二胺、壬醛、2,4-二叔丁基酚、2,6-二叔丁基对甲酚等12 种成分需引起关注。通过查阅资料,共确定14 种挥发性气味物质,其中壬醛、正十一烷和正十六烷等可能对自热食品聚丙烯包装的气味有潜在贡献。本研究为自热食品聚丙烯包装挥发性成分的分析提供一定的方法依据,并为自热食品聚丙烯包装的安全性评估和气味分析提供数据支持。     

Comparison of dynamic headspace and simultaneous distillation extraction techniques used for the analysis of the volatile components in three European PDO ewes’ milk cheeses

This preliminary study aims to compare two different extraction and concentration methods often used for the gas chromatographic analysis of volatile components in food to determine the advantages and drawbacks of both for future routine investigation of PDO (protected designation origin) ewes’ milk cheeses. Roncal, Pecorino Sardo and Fiore Sardo were investigated at different ripening stages. The dynamic headspace technique using a Purge & Trap device (DHS) makes it possible to extract more highly volatile compounds than the simultaneous distillation extraction (SDE) method. Consequently, the latter is more efficient for extracting low-volatile components such as phenols, free fatty acids, lactones and longer-chain aldehydes, ketones, alcohols and esters. These two extraction methods are therefore complementary.     

黑果腺肋花楸挥发油化学成分及总黄酮含量分析研究

目的研究黑果腺肋花楸挥发性化学成分的组成及质量分数,分析其总黄酮含量。方法采用超声波提取法提取黑果腺肋花楸果实中的挥发油和总黄酮,挥发油的化学成分通过气相色谱-质谱法(gas chromatography-mass spectrometer, GC-MS)进行分析鉴定,各挥发性化学成分的质量分数采用色谱峰面积归一化法计算。以芦丁为标准品,用紫外可见分光光度仪进行总黄酮含量的分析测定。结果黑果腺肋花楸挥发油经GC-MS分析,共鉴定出36个挥发性化学成分,占挥发油色谱总峰面积的84.14%。芦丁标准品呈现良好线性关系(r~2=0.9997),总黄酮类化合物的平均含量为0.233%,标准偏差(standard deviation,SD)为0.01291,相对标准偏差(relative standard deviation, RSD)为5.53%。结论黑果腺肋花楸中的挥发性成分以烷烃类、酯类、羧酸类、醇类几类化合物为主,其果实中总黄酮类化合物的含量较低。     

HS-GC-O-MS分析细叶韭花易挥发性风味成分

采用顶空-气相色谱-质谱联用技术对细叶韭花中易挥发性成分的萃取条件及气相色谱-质谱分离检测条件进行系统研究,并结合嗅闻仪确定挥发性风味成分。在选定HP-5MS色谱柱的分离条件下,最优顶空条件为样品用量1.0 g/20.0 mL顶空瓶,平衡温度100℃,平衡时间40 min。结果表明:经气相色谱-嗅闻-质谱联用分析,共分离得到52种化合物,确定结构46种,占总易挥发性成分的99.15%。其中,含硫类17种、醛类10种、烃类4种、酮类4种、呋喃类3种、醇类4种、酸类2种、芳香族类1种、萜类1种。根据嗅闻结果结合相对气味活度值可得,细叶韭花挥发性风味成分主要是二甲基硫醚、二甲基二硫醚、二甲基三硫醚、3-甲基丁醛、2-甲基丁醛、1,3-二噻烷。     

基于SHS-GC-MS和GC-IMS的对两种雪茄烟挥发性香味成分的分析与研究

【目的】为明确雪茄烟挥发性香味成分,比较不同雪茄烟挥发性香味成分的差异性。【方法】采用静态顶空-气质联用仪（SHS-GC-MS）和气相色谱离子迁移谱（GC-IMS）两种分析检测技术,对长城2号和蒙特4号两种雪茄烟的挥发性香味成分进行检测,并结合主成分分析（PCA）和偏最小二乘-判别分析（PLS-DA）方法分析了两种雪茄烟的香味主要差异成分。【结果】（1）从嗅香来看,两支雪茄烟的主体香韵均为较为明显的晾晒烟特征香气和蜂蜜样的甜香。蒙特4号的花香、木香和可可香气更加明显一些,长城2号的甜香和膏香则相对较强,并稍带果甜,香气比较厚实浓郁。（2）通过SHS-GC-MS分析检测技术从长城2号雪茄烟中鉴定出18种挥发性香味成分,从蒙特4号中鉴定出30种挥发性香味成分;蒙特4号中异龙脑、乙酸异龙脑酯、α-柏木烯、罗汉柏烯等成分的含量明显高于长城2号;而3,5-二甲基苯酚和6-甲基-5-庚烯-2-酮两种香味成分仅存在于长城2号中。（3）GC-IMS在两种雪茄烟中共鉴定出47种成分,包括了3种酸类、4种酯类、12种酮类、10种醛类、11种醇类、2种杂环类和5种烯烃类成分;运用PCA和PLS-DA的分析方...     

顶空固相微萃取-气相色谱-质谱法测定香紫苏香气成分

目的建立一种利用顶空固相微萃取-气相色谱-质谱法快速测定香紫苏香气成分的方法。方法采用顶空固相微萃取-气相色谱-质谱联用技术,对新疆香紫苏香气成分进行测定分析,并采用面积归一化法计算各成分的相对含量。结果共鉴定出18种化学成分,主要成分为乙酸芳樟酯(79.58%)及芳樟醇(8.32%)。结论顶空固相微萃取与气相色谱-质谱联用技术具有样品用量少、前处理过程简单等优点,适用于测定香紫苏香气成分。     

Observations on the use of porous polymers for collecting volatiles from synthetic mixtures reminiscent of fermented ciders

Conditions for collecting volatile components on Porapak Q and desorbing them for gas chromatographic examination have been investigated using a synthetic mixture representing the aroma components of cider. Optimum recoveries and least errors were obtained using a piston displacement procedure, 32 mg of Porapak, a temperature of 150°C for 20 min for desorption and ratios of vapour to liquid not exceeding 5:1. Tenax GC gave more consistent results than Porapak Q for non-polar compounds with boiling points greater than that of hexyl acetate.     

GC-O-MS法检测句容产区巨峰葡萄香气成分分析

目的：对句容产区巨峰葡萄的挥发性香气成分进行分析。方法：采用固相微萃取技术富集巨峰葡萄浆果中的挥发性香气成分,采用气相色谱-嗅闻-质谱联用技术进行检测,香气成分经质谱标准谱库检索并结合保留指数及嗅闻结果进行定性分析,采用内标法进行定量分析。结果：在巨峰葡萄中共鉴定出50 种挥发性香气成分,占检出香气总量93.05%,并对各香气化合物进行分类分析,确定14 种巨峰葡萄香气的特征成分及香气轮廓。结论：与其他产区巨峰葡萄特征香气成分对比,产区因素可能是导致不同葡萄产区巨峰葡萄特征香气成分差异的主要原因之一。