气相色谱-质谱法分析歧化松香中性部分的化学组成

用皂化法将歧化松香中的酸性和中性部分分离,并由GC/MS法对中性部分的化学组成进行了分析,为进一步拓宽松脂可再生资源的用途提供了科学依据。实验考察了中性部分化学组分分析的GC和MS条件,检索对照了NIST数据库的标准图谱,结果表明,歧化松香中性部分共分离出55个组分,其中高沸点中性部分共分离出32个组分,鉴定了其中的30个组分(占歧化松香中性物质质量的80.3%,下同),主要化学成分为:脱氢枞酸甲酯、7-二氢海松酸甲酯、8(14)-二氢异海松酸甲酯、8α-四氢异海松酸甲酯、7-二氢枞酸甲酯、8-二氢海松酸甲酯、8α-四氢海松酸甲酯以及4个高沸点化合物;低沸点中性部分分离出23个组分,鉴定了其中的22个组分(占歧化松香中性物质质量的19.7%),主要是倍半萜和少量单萜化合物,系残留的歧化松节油。     

不同陈化年份鸢尾挥发性成分的分析研究

为了研究不同陈化年份鸢尾挥发性成分的变化情况,采用同时蒸馏萃取方法分别提取不同陈化年份鸢尾的挥发性成分,将得到的挥发油通过气相色谱-质谱仪进行分离和鉴定,采用峰面积归一化法确定各成分的相对质量分数。从4个不同陈化年份鸢尾挥发油中分别鉴定出37、39、39和38种成分,分别占总量的63.0%、70.4%、75.0%和65.7%。这些成分主要由酸类、酮类、酯类和醛类等化合物组成,其中十四酸、正癸酸、十二酸、6-甲基-α-紫罗兰酮、α-鸢尾酮和辛酸等是主要成分。结果表明,3年陈化的鸢尾挥发油得率最高,得到鉴定的挥发性成分个数最多,其挥发性成分在总成分中所占质量比最大,因此鸢尾的陈化时间选择3年较佳。     

SDE-GC-MS分析柴沟堡熏肉挥发性风味成分

采用同时蒸馏萃取法(simultaneous distillation and extraction,SDE)提取柴沟堡"郭玺"熏肉的挥发性风味成分,结合气相色谱-质谱联用技术(gas chromatogrophymass spectrometry,GC-MS)对其进行分析鉴定。结果共鉴定出82种挥发性成分,其中,烃类17种(相对质量分数8.728 3%),醛类23种(相对质量分数57.723 3%),醇类12种(相对质量分数4.042%),酮类10种(相对质量分数2.719 2%),酯类3种(相对质量分数1.947%),酚类9种(相对质量分数6.237 2%),醚类1种(相对质量分数2.406 4%),杂环化合物7种(相对质量分数2.814 1%)。其中,醛类、酚类、含硫含氮及杂环化合物对熏肉的风味可能有较为显著的影响。     

葫芦巴浸膏挥发性成分分析

采用同时蒸馏法萃取葫芦巴浸膏中的挥发性成分,并用气相色谱-质谱联用技术进行分析鉴定,鉴定出46种化学成分,应用峰面积归一化法确定了各成分的相对质量分数。葫芦巴浸膏挥发性香气成分主要包括棕榈酸乙酯(30.34%)、亚油酸乙酯(21.53%)、油酸乙酯(12.96%)、正己酸乙酯(4.96%)、肉豆蔻酸乙酯(2.23%)、辛酸乙酯(1.89%)、十五酸乙酯(1.28%)等。     

低盐固态发酵酱油中挥发性风味物质的分析

为促进低盐固态发酵酱油产品风味的提高与改善,运用固相微萃取-气质联用技术对低盐固态发酵酱油的挥发性风味成分进行了分析,共鉴定了55种挥发性风味成分,总相对质量分数为96.60%,其中醇类化合物为54.86%;苯酚类化合物为4.05%;酯类化合物为2.78%;醛类化合物为7.82%;酮类化合物为1.25%;酸类化合物为9.90%;胺类化合物为1.67%;杂环类化合物为4.02%;烃类化合物为10.25%。低盐固态发酵酱油的主体挥发性风味成分为醇酚类、酸类、醛酮、杂环化合物,这为提高和改进低盐固态发酵酱油的风味提供了依据。酱油风味的形成是多种化合物共同作用的复杂反应。     

炒甘草浸膏挥发性成分分析

采用同时蒸馏方法萃取炒甘草浸膏中的挥发性成分,并用气相色谱-质谱联用技术进行分析鉴定,鉴定出28种化学成分,应用峰面积归一化法确定了各成分的相对质量分数。炒甘草浸膏挥发性香气成分主要包括糠醛(18.44%)、5-甲基呋喃醛(14.52%)、2-乙酰基呋喃(13.37%)、棕榈酸甲酯(9.62%)、棕榈酸(9.06%)、糠醇(8.05%)、亚油酸乙酯(4.77%)、亚油酸(2.79%)等。     

不同压力下猪肉香精挥发性风味成分的差异性

为了考察不同压力下猪肉香精挥发性风味成分的差异性,采用固相微萃取法(SPME)分别萃取常压和加压热反应条件下制备的猪肉香精中挥发性风味成分,并结合气相色谱-质谱联用技术(GC-MS)和气相色谱-嗅闻技术(GC-O)进行鉴定。结果显示:常压制备的猪肉香精中共鉴定出45种挥发性成分,其种类及质量分数分别为:烃类5种(6.58%),醛类16种(21.20%),醇类10种(6.07%),酸类8种(3.15%),杂环及其他化合物6种(37.19%)。加压制备的猪肉香精中共鉴定出38种挥发性成分,包括烃类3种(1.49%),醛类14种(9.65%),醇类6种(1.96%),酯类、酮类和酸类共计5种(2.89%),杂环及其他化合物10种(47.73%)。两者均鉴定出的化合物有22种,包括苯甲醛、枯茗醛、蘑菇醇、4-甲基-5-羟乙基噻唑、茴香脑等。通过常压热反应方式制备的猪肉香精中主要挥发性风味成分较多,更接近厨房菜肴。     

白象牙芒果中挥发性成分的分析

采用同时蒸馏萃取,提取芒果果实中的挥发性成分,经气相色谱-质谱联用仪对芒果挥发性香味化合物进行分离和鉴定,确认了其中的68种成分,占总质量分数的95.40%,并用面积归一化法测定了各种成分的质量分数,其主要成分为异松油烯(44.86%)、3-蒈烯(7.06%)、棕榈酸(6.04%)、亚麻酸(3.44%)、4-蒈烯(3.14%)、苧烯(2.44%)、α-水芹烯(2.95%)等.     

亳菊香料超声波提取工艺优化及挥发性成分分析

以亳菊香料浸膏提取率为考察指标,采用L9(34)正交实验法进行优选。采用同时蒸馏萃取装置收集挥发性成分并用气相色谱-质谱仪进行分析和鉴定。最佳提取条件为:超声波功率800 W,提取时间30 min,乙醇体积分数70%。共鉴定出88种化合物,用峰面积归一化法测定各组分的峰面积百分比为:顺-香橙烯9.38%、n-棕榈酸5.11%、β-人参烯4.63%、长叶醛4.36%、α-雪松烯氧化物3.97%、桉双烯酮3.67%、异香橙烯环氧化物3.35%、1-氟-2-(Z-2-甲氧基)苯3.17%、α-衣兰烯3.15%、亚油酸2.68%、异香橙烯2.54%、α-香附酮2.35%等。优选得到的工艺可提高亳菊香料浸膏的提取率。     

储藏条件对啤酒花化学组成的影响

研究了香型啤酒花扎一(SA-1)和苦型啤酒花奴革特(Nugget)、齐洛克(Ch inook)、马可波罗(M arco Polo)、青岛大花(Tsingdao flower)5个啤酒花品种在不同的储藏条件下其化学组成的变化。这些啤酒花样品分别在-10~-12℃、0~2℃和室温(20℃左右)3种条件下避光保存180 d,并定期对其主要成分α-酸、β酸、啤酒花多酚和储藏指数等指标进行分析。结果表明:样品中的各组分都发生了不同程度的质量劣变,这些变化不仅和储藏条件有关,也与品种有关。室温下储藏的啤酒花的酿造价值下降最为严重,而较低的储藏温度也只能在一定程度上减缓其氧化的速率。香型啤酒花扎一的损失率最高,在室温下储存120 d时,其α-酸的质量分数只有采收时的45.53%;合葎草酮质量分数较低的苦型啤酒花奴革特的损失率最低,在低于2℃的储存条件下,即使保存时间已达到180 d,它也还有采收时α-酸量的77.23%。     

MAE-SPME联合提取GC-MS检测草莓果实中的香气成分

分别采用溶剂萃取法(SE)、固相微萃取法(SPME)和微波辅助-固相微萃取(MAE-SPME)联用技术等前处理方法提取草莓果实中香气物质,通过气相色谱-质谱(GC-MS)联用仪对挥发性成分进行了分离鉴定。结果表明,不同的前处理方法所得结果相差甚远,MAE-SPME联用技术前处理方法提取后,可鉴定到85种化合物,其中酯类53种,其他依次是醛类、酮类、醇类、酸类、醚类、烯烃、芳香烃和杂环化合物等;而用SE法、SPME法提取,分别仅鉴定到26种和16种香气物质。说明微波辅助-固相微萃取两种技术联用,是一种能较好地提取果蔬中香气物质的样品前处理技术。     

顶空固相微萃取对新疆麻黄挥发成分的分析

用顶空固相微萃取法分析了新疆地产野生蓝麻黄、中麻黄和木贼麻黄的挥发成分,共鉴定出167种化学成分,测定了各成分的相对质量分数并进行了比较,发现这3种麻黄草中所含的挥发成分有显著差异。其中,从蓝麻黄中鉴定出97种化合物,烯烃类化合物为其主要成分,占总峰面积的68.59%,含量最多的化合物是β-月桂烯,占总峰面积的28.10%;从中麻黄中鉴定出68种化合物,烯烃类化合物为其主要成分,占总峰面积的55.97%,含量最多的化合物是β-月桂烯,占总峰面积的25.42%;从木贼麻黄中鉴定出69种化合物,烯烃类化合物为其主要成分,占总峰面积的54.05%,含量最多的化合物是(1S,5S)-2(10)-蒎烯,占总峰面积的32.73%。     

MAE-HS-SPME联合萃取GC-MS分析肉桂香气成分

采用微波辅助萃取与顶空-固相微萃取联合(MAE-HS-SPME)的方法萃取肉桂中香气成分,用气相色谱-质谱(GC-MS)法进行分析,并将分析结果与同时蒸馏萃取法(SDE)和HS-SPME法对比。结果表明,MAE-HS-SPME的最佳条件为:称取10g样品,加入100mL去离子水,微波功率为150W,用100μmPA萃取头萃取4.5min,250℃解吸20s。GC-MS分析确认了其中62种成分,占总峰面积的95.01%。3种萃取方法所得肉桂中主要香气成分基本相同,均为桂醛、α-荜澄茄烯、反式茴香脑和4,7-二甲基-1-异丙基-[1α,4aα,8aα]-1,2,4a,5,6,8a-六氢萘等。MAE-HS-SPME法鉴定的成分比HS-SPME和SDE法分别多出18种和26种。说明MAE-HS-SPME是一种分析肉桂中香气物质的高效的样品前处理方法。     

Analysis of flavor quality and residual solvent of soy protein products

A simple, direct, gas Chromatographic technique is described for eluting and resolving residual solvent and flavor-related volatile components from soy products such as flour and protein isolates. No prior enrichment of volatiles is necessary. A sample, together with a small amount of water, is secured in a glass liner and placed in the heated injection port of a gas Chromatograph. The volatiles are rapidly steam distilled from the sample by the heat, moisture, and flow of carrier gas and are adsorbed on the chromatographic column in situ. Residual solvent and other volatiles adsorbed on the column are resolved by temperature-programmed gas chromatography and identified by combined gas chromatography-mass spectrometry. The correlation between taste panel flavor score and concentration of volatile components is significant at the 1% level. Presented at the AOCS Meeting, New York, May 1977.     

Thet complex of the mouse: Chemical characterization by urinary volatile profiles

Urine samples from C3H congenic house mice (Mus domesticus) differing only at thet complex were examined by capillary gas chromatography to assess variations in the volatile components that may cause olfactory discrimination between animals bearingt lethal and+(wild-type) haplotypes. Urine was collected from 192 males and females varying in age from 1 to 9 months. C3H congenic mice that have the same genetic background at all loci but differed in theirt complex genotypes: +/ +, +/t_w1,T/t _w1, T/+ were used. No urinary volatiles were unique to thet complex. However, significant differences amongt complex genotypes and among ages occurred for concentrations of 12 male volatiles and four female volatiles. Usually young males (1–2 months of age) had significantly higher concentrations of cyclic enol ethers and ketones than older males (4–9 months of age). Moreover, some urinary volatiles (cyclic enol ethers, one ketone, dehydrobrevicomin, and thiazoline) were excreted in the urine of T/+and/orT/t males in significantly higher concentration than in the urine of +/+ males. Age andt complex genotype influences on the urinary volatiles in females were observed for four ketones. Gas chromatography of urinary components has the potential to be used in field studies of thet complex because the two t complex genotypes found in wild populations, +/+ and +/t, had significant differences in concentration for two males volatiles and three female volatiles.We dedicate this paper to the memory of Dorothea Bennett.On leave from the Environmental Protection Institute, Ministry of Light Industry, Beijing, China.A.E.M.B. supported in part by NSF BSR 8909172.     

Citrus Leaf Volatiles as Affected by Developmental Stage and Genetic Type

Major volatiles from young and mature leaves of different citrus types were analyzed by headspace-solid phase microextraction (HS-SPME)-GC-MS. A total of 123 components were identified form nine citrus cultivars, including nine aldehydes, 19 monoterpene hydrocarbons, 27 oxygenated monoterpenes, 43 sesquiterpene hydrocarbons, eight oxygenated sesquiterpenes, two ketones, six esters and nine miscellaneous. Young leaves produced higher amounts of volatiles than mature leaves in most cultivars. The percentage of aldehyde and monoterpene hydrocarbons increased, whilst oxygenated monoterpenes and sesquiterpenes compounds decreased during leaf development. Linalool was the most abundant compound in young leaves, whereas limonene was the chief component in mature ones. Notably, linalool content decreased, while limonene increased, during leaf development in most cultivars. Leaf volatiles were also affected by genetic types. A most abundant volatile in one or several genotypes can be absent in another one(s), such as limonene in young leaves of lemon vs. Satsuma mandarin and β-terpinene in mature leaves of three genotypes vs. the other four. Compositional data was subjected to multivariate statistical analysis, and variations in leaf volatiles were identified and clustered into six groups. This research determining the relationship between production of major volatiles from different citrus varieties and leaf stages could be of use for industrial and culinary purposes.     

Variations in mouse (Mus musculus) urinary volatiles during different periods of pregnancy and lactation

Mouse urine samples from different pregnancy and lactation periods were examined by capillary gas chromatography to assess variations in the volatile signals that may affect the endocrine function of other females. Statistically significant changes in the excretion of certain urinary volatiles were observed; from 26 readily quantifiable constituents, 14 appear to be under the endocrine control. These selected components, positively identified through mass spectrometry and retention data, and the synthetic standards are ketones, unsaturated alcohols, esters, and cyclic vinyl ethers.     

Effects of High-Temperature Drying on the Flavor Components in Thai Fragrant Rice

The effects of high-temperature drying on Thai Jasmine rice were investigated. Paddy was first rewetted and then dried using a two-stage drying process, involving a fluidized bed at high temperature, followed by shade drying (ambient air drying). Three high drying temperatures: 100, 125, and 150°C were studied. Volatile compounds were extracted by distillation and extraction in a Likens and Nickerson apparatus, and analyzed by gas chromatography-mass spectrometry. A total of 94 volatile compounds were identified. These included 21 alcohols, 19 aldehydes, 14 ketones, 12 acids, 9 heterocyclic compounds, 8 hydrocarbons, 5 esters, and 6 miscellaneous compounds. 2-Acetyl-1-pyrroline, a major constituent of volatiles in fragrant rice was identified and tended to increase in concentration with increasing drying temperature. The three different drying temperatures used in the fluidized bed dryer were found to have an effect on the volatile components of Thai Jasmine rice. The increase in drying temperature contributed to the formation of new compounds, as well as the loss of other desirable volatiles.     

Volatile components from trilinolein heated in air

Pure trilinolein and mixtures of trilinolein-tristearin, trilinolein-triolein, and trilinolein-triolein-tristearin were heated to 192 C in air. Volatiles were collected, separated, and identified by gas chromatography-mass spectrometry. Major volatiles observed from each heated sample produced compounds unique to the autoxidation-decomposition of the trilinolein component and included: pentane, acrolein, pentanal, 1-pentanol, hexanal, 2- and/or 3-hexenal, 2-heptenal, 2-octenal, 2,4-decadienal, and 4,5-epoxydec-2-enal. When samples containing both trilinolein and triolein were heated, volatiles were produced that could be ascribed to each triglyceride. However, heated mixtures containing tristearin produced no observable volatiles that could be related to the oxidized saturated triglyceride. Minor volatiles identified from the heated trilinolein and its mixtures included; aliphatic acids, saturated and unsaturated aldehydes, primary and secondary alcohols, gamma lactones, furans, hydrocarbons, and methyl ketones.     

Identification of volatile allelochemicals fromAmaranthus palmeri S. Wats

Allelopathic volatiles associated with the weed Palmer amaranth (Amaranthus palmeri S. Wats.; AMAPA) were trapped on Tenax GC, thermally desorbed, and identified by gas chromatography-mass spectroscopy. Methyl ketones and alcohols (C₄–C₁₁) were the principal components of the volatiles mixture. Seedheads, stems, or roots were placed in a glass container and incubated at 31 °C (10 hr)/21 °C (14 hr) for three days prior to trapping the volatiles. Seedheads were rich in 2-heptanone which was consistently found, together with 2-heptanol, in all AMAPA tissues. Vapors of authentic 2-heptanone and (±)-2-heptanol at concentrations of 1 ppm or higher strongly inhibited the germination of onion and carrot and almost completely suppressed the germination of tomato and AMAPA seeds.Names of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned.