GC-O-MS分析热处理前后西瓜汁挥发性风味成分

利用GC-O-MS分析热处理前后西瓜汁的挥发性有机物风味成分。结果表明,GC-O-MS鉴定出鲜榨西瓜汁44种气味化合物,热处理西瓜汁50种气味化合物。结合嗅闻、气味稀释因子和香气活性值确定鲜榨西瓜汁中的关键气味化合物是壬醛(清香、青草味)、反-2-壬烯醛(清香、黄瓜味)、反,顺-2,6-壬二烯醛(清香、黄瓜味)、反,顺-3,6-壬二烯醇(清香、黄瓜味)、反,顺-2,6-壬二烯醇(清香、黄瓜味)和香叶基丙酮(花香、甜味);热处理西瓜汁中关键气味化合物为反-2-庚烯醛(脂味、苦味)、1-癸醛(脂味、肥皂味)、6-甲基-5-庚烯-2-酮(蘑菇味、霉味)、苯乙酮(苦杏仁味)、二乙基二硫醚(大蒜味)和顺-6-壬烯醛(臭味、刺激味)。顺-6-壬烯醛特征气味原为清香、黄瓜味,而热处理西瓜汁中顺-6-壬烯醛的含量增大,超过感官评价员鼻子的耐受值,呈现臭味、刺激味。热处理产生了异味成分,气味化合物的变化导致了西瓜汁加热后的蒸煮味。     

Volatile Compounds Characterizing the Aroma of Fresh Atlantic and Pacific Oysters

Volatile compounds which contribute to the distinct melon-like aroma of fresh Pacific oysters (Crassostrea gigas) were identified as (E,Z)-2,6-nonadienal and 3,6-nonadien-1-ol, but these compounds were not found in the less intensely flavored Atlantic oysters (Crassostrea virginica). 1-Octen-3-one, 1-octen-3-ol, 1,5-octadien-3-one, 1,5-octadien-3-ol, and 2,5-octadien-1-ol were found in both species of oysters, and contributed a characteristic heavy, planty aroma to each. Sensory panel scores for intensity of fresh melon-like flavors were significantly higher for both raw and steamed Pacific oysters than for comparable Atlantic oysters. Enzymic generation of alcohols and carbonyls that comprise the characterizing aroma compounds from polyunsaturated fatty acids was demonstrated by preventing their formation with specific inhibitors for cyclooxygenase (acetylsalicylic acid) and lipoxygenase [tin (II) chloride].     

基于AEDA和OAV值确定西瓜汁香气活性化合物的比较

本研究采用溶剂辅助风味蒸发提取西瓜汁的香气成分,利用气相色谱-质谱联用结合嗅闻仪定性定量分析其香气活性化合物,共鉴定出49种化合物,主要是小分子的酮、醛、硫醚等物质,酯类物质中只检测到一种物质,即乙酸乙酯,且浓度较低。本研究首次检测到醚类物质。OAV计算和AEDA两种方法共同鉴定出11中物质,顺,顺-3,6-壬二烯醛、顺-3-壬烯-1-醇、反,顺-3,6-壬烯-1-醇、反-2-壬烯醛、壬醛、1-壬醇、2-戊基呋喃、己醛、辛醛、顺-6-壬烯醛、反-2-辛烯醛。其中有五种香气活性物质,即顺,顺-3,6-壬二烯醛、顺-3-壬烯-1-醇、顺-6-壬烯醛、顺-2-壬烯醛、反,顺-3,6-壬烯-1-醇都能被实验员嗅闻到,且具有较高的OAV值。这表明,AEDA和OAV计算在西瓜汁香气活性化合物分析上具有一定的相似性。     

顶空固相微萃取-气相色谱-质谱联用法分析美藤果油中的挥发性成分

采用顶空固相微萃取法提取美藤果油中的挥发性成分,并通过气相色谱-质谱联用技术对其进行分析鉴定,采用峰面积归一化法确定各成分的相对含量。结果表明:美藤果油中共鉴定出46种挥发性成分,占挥发性成分总量的86.73%,主要有(2E,4E)-2,4-庚二烯醛、(2E,4Z)-2,4-庚二烯醛、乙酰基环己烯、(E,E)-3,5-辛二烯-2-酮、3,5-辛二烯-2-酮、反式-2-戊烯、正己醛、(E)-2-庚烯醛等,以醛类、酮类和烃类化合物为主,并含有少量的醇类和呋喃类化合物。     

Fishy and hay-like off-flavours of dry spinach

 Gas chromatography-olfactometry of headspace samples revealed that (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine are potent odorants of raw spinach. Boiling the spinach led to a change, such that dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline became the most important odorants. A further change was observed after drying and storage of raw spinach: methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. It was also found that (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour as dry spinach stored at lower temperatures under nitrogen. The hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. Received: 24 July 1997     

Fishy and hay-like off-flavours of dry spinach

 Gas chromatography-olfactometry of headspace samples revealed that (Z)-3-hexenal, methanethiol, (Z)-1,5-octadien-3-one, dimethyl trisulphide, octanal, 2-isopropyl- and 2-sec-butyl-3-methoxypyrazine are potent odorants of raw spinach. Boiling the spinach led to a change, such that dimethyl sulphide, methanethiol, dimethyl trisulphide, methional and 2-acetyl-1-pyrroline became the most important odorants. A further change was observed after drying and storage of raw spinach: methylpropanal, 2- and 3-methylbutanal and propanal were identified as the odorants with higher odour activity values. It was also found that (Z)-1,5-octadien-3-one and methional, in a concentration ratio of about 1 : 100, are responsible for the fishy off-flavour as dry spinach stored at lower temperatures under nitrogen. The hay-like flavour was caused by oxidative degradation of furan fatty acids, yielding 3-methyl-2,4-nonanedione. Received: 24 July 1997     

Influence of Maturity on the Volatile Aroma Compounds from Fresh Pacific and Great Lakes Salmon

Volatile aroma compounds from freshly harvested prime and spawning-condition salmon (Oncorhynchus sp.) from the Pacific Ocean (chi-nook, sockeye, chum, coho and pink) and the Great Lakes (chinook, coho and pink) were quantitatively measured. Both prime and spawning-condition salmon had 1-octen-3-one, 1,5-octadien-3-one, 1-octen-3-ol, 1,5-octadien-3-ol, 2-octen-1-ol, and 2,5-octadien-1-ol which contributed distinct and characteristic plant-like aromas to the fish. More pronounced aromas of spawning-conditions almon were attributed to greater concentrations of the 8-carbon compounds in combination with occurrence of (E)-2-nonenal, (E)-2,(Z)-6-nonadienal, 6-nonen-1-ol, and 3,6-nonadien-1-ol which added sweet, cucumber- or melon-like aroma notes. The 9-carbon compounds may have resulted from biochemical regulation of physiologically active lipid-derived substances which activate mucus secretion in salmon approaching sexual maturity.     

Important odorants of sweet bell pepper powder (Capsicum annuum cv. annuum): differences between samples of Hungarian and Morrocan origin

 By application of gas chromatography–olfactometry on aroma extracts prepared from Hungarian sweet bell pepper powder (HBP) and Moroccan sweet bell pepper powder (MBP), 35 and 42 odour-active compounds were detected in the HBP and the MBP, respectively. The identification experiments, in combination with the flavour dilution (FD) factors obtained by application of aroma extract dilution analysis, revealed that β-ionone (violet-like), 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol; caramel-like), 3-hydroxy-4,5-dimethyl-2(5H)-furanone (Sotolon; seasoning-like) and 2- and 3-methylbutanoic acids had the highest odour activities (FD factors of 8192 to 32768) among the 33 odorants that could be identified in the HBP. All odorants identified in the HBP were also characterized as odour-active volatiles in the MBP. The overall different aroma of the Moroccan sample could, however, be attributed to the lower FD factors of the five key odorants mentioned above and, in addition, to the higher FD factors of 10 odorants not present among the aroma compounds of the HBP, e.g. (Z)-1,5-octadien-3-one. In total, 20 odour-active volatiles are reported here for the first time as volatile bell pepper constituents. Received: 30 July 1999 / Revised version: 11 October 1999     

Investigating volatile compounds’ contributions to the stale odour of green tea

This study aimed to characterise the volatiles that contribute to stale odour of green tea. Volatiles were extracted using headspace solid-phase microextraction (HS-SPME) and analysed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Results showed that a total of ninety-six volatiles were identified by GC-MS, in which forty-four volatiles were screened out based on Principal component analysis (PCA) and orthogonal projections to latent structures–discriminant analysis (OPLS-DA), and thirty-nine volatiles had a significant variation at the level of 0.05 by analysis of variance (anova ). From GC-O analysis, fifty-four aromatic volatiles with strong aroma intensity (aroma intensity above 2) were perceived. Further investigation revealed that fifteen volatiles, including 1-octen-3-ol, benzyl alcohol, benzaldehyde, safranal, β-cyclocitral, (E,E)-3,5-octadien-2-one, (Z,E)-3,5-octadien-2-one, dimethyl adipate, dihydroactinidiolide, β-ionone, α-ionone, geranyl acetone, phenylethyl alcohol, methyl decanoate and α-terpineol were responsible for stale odour, besides the former nine compounds were only found in stored tea.     

Compounds Contributing to the Odor of Aqueous Slurries of Soy Protein Concentrate

ABSTRACT: Gas chromatography olfactometry/mass spectrometry (GCO/MS) studies on static and concentrated headspace of the aqueous slurries from soy protein concentrate (SPC) revealed acetaldehyde, methanethiol, hexanal, dimethyl trisulfide (DMTS), and 2-pentyl furan as the most odorous volatiles. Further aroma extract dilution analysis (AEDA) of the volatile extracts identified the following as the odorous substances: hexanal, 2-heptanone, octanal, 2-octanone, 1-octen-3-one, DMTS, 3-octen-2-one, 2-decanone, benzaldehyde, 2-pentyl pyridine and trans, trans -2,4- nonadienal, along with several unidentified odorants. Methanethiol and acetaldehyde, which have low boiling points, were not detected by AEDA, however. This is the first time that acetaldehyde, methanethiol, and dimethyl trisulfide have been identified as primary odorants in SPC.     

白姑鱼和小黄鱼肉中挥发性风味物质的鉴定

采用新型固相萃取整体捕集剂（Mono-Trap）结合气相色谱-质谱-嗅闻技术对白姑鱼和小黄鱼肉的挥发性风味物质进行鉴定,分别得到42 种和49 种挥发性成分。进一步通过芳香萃取物稀释分析法分别从白姑鱼和小黄鱼肉挥发物中筛选出12 种和6 种挥发物,其中9 种挥发物经质谱和线性保留指数鉴定。进一步结合校准频率（modified frequency,MF）法,各筛选出2 种鱼肉中排名前10的气味物质。白姑鱼中香气稀释（flavor dilution,FD）因子最高为40的化合物为三甲胺、2-辛烯-1-醇、壬醛及金属味未知化合物。结合MF排名,得到三甲胺和2-辛烯-1-醇对白姑鱼贡献较大;小黄鱼中FD因子最高为40的化合物为己醛和2-辛烯-1-醇,但结合MF排名,对其气味贡献较大的是三甲胺和未知烧烤味化合物。6-甲基-5-庚烯-2-酮为2 种鱼中均鉴定出的一种带金属味或血腥味成分,根据MF排名,该化合物对白姑鱼影响更大。2,3-戊二酮、1-戊烯-3-醇为小黄鱼中MF较靠前的物质,结合三甲胺和未知烧烤味化合物以及白姑鱼中未鉴定到的二甲基二硫醚,这些挥发物可能是造成其与白姑鱼气味感知差异的原因。     

Effect of addition of commercial rosemary extracts on potent odorants in cooked beef

Solid-phase microextraction-gas chromatography-olfactometry (SPME-GCO) and aroma extract dilution analysis (AEDA) were applied to measure the effects of the addition of two commercial rosemary extracts (RE) on the potent odorants in cooked beef extracts (BE). On the basis of the results of SPME-GCO and AEDA, the addition of RE imparted sweet and floral notes to BE as a result of the addition of esters and terpenes of RE. In addition, RE suppressed the formation of odorants derived via lipid oxidation and Maillard reactions. The most potent lipid oxidation volatiles consisted of 1-octen-3-one (mushroom-like), (E)-2,4-epoxy-(E)-2-decenal (metallic), and eight different aldehydes (fatty). The Maillard reaction volatiles, necessary for typical cooked beef flavor, included compounds with meaty [2-methyl-3-furanthiol, 2-methyl-3-(methylthio)furan, 2-methyl-3-(methyldithio)furan], roasty (2-furanmethanethiol), caramel-like [4-hydroxy-2,5-dimethyl-3(2H)-furanone], baked potato-like [3-(methylthio)propanal], and spicy [3-hydroxy-4,5-dimethyl-2(5H)-furanone] attributes. The suppressive effects of RE may be caused by the action of antioxidative substances in RE alone or in combination with the pH increase in BE induced by the matrix components of RE.     

MMSE-GC-MS/GC-O法鉴定熟制阳澄湖大闸蟹关键嗅感物质

本文采用新型材料-MonoTrap作为固相萃取整体捕集剂,提取阳澄湖大闸蟹的挥发性成分。利用气相色谱-质谱联用仪(GC-MS)对雄性、雌性阳澄湖大闸蟹四个部位(体肉、钳肉、足肉和性腺)中的挥发性成分进行了分离鉴定,共得到9大类76种挥发性物质。同时,采用气相色谱-嗅闻技术(GC-O)并运用直接强度法对挥发物进行分析,共嗅闻到17种气味特征,其中体肉气味特征强度最弱,性腺最强。青草味是四个部位中最显著的气味特征,而性腺气味特征较其他部位不同的是具有较强的油脂味和烤肉味。在76种挥发性物质中,筛选出56种具有气味特征的嗅感物质(Odor Compound,OC),其中三甲胺、(Z)-4-庚烯醛、2,5-二甲基吡嗪、(E,E)-3,5-辛烯-2-酮和(Z)-4-癸烯醛在各可食部位中均存在,对阳澄湖大闸蟹的典型风味贡献显著。     

南极磷虾头胸部和腹部挥发性风味成分对比

采用顶空固相微萃取-气相色谱-质谱联用技术分析南极磷虾头胸部、腹部和整虾的挥发性风味成分,结合感觉阈值,利用相对气味活度法评价挥发性风味成分对总体风味的影响程度。结果表明,南极磷虾头胸部的主体风味成分为（E,Z）-2,6-壬二烯醛、3-甲基丁醛、3-甲硫基丙醛、壬醛、苯乙醛、D-柠檬烯、（Z）-4-庚烯醛、二甲基硫醚、辛醛、苯甲醛;南极磷虾腹部主体风味成分为二甲基三硫醚、癸醛、壬醛、3-甲基丁醛、辛醛、二甲基硫醚、D-柠檬烯、（Z）-4-庚烯醛;整虾的主体风味成分则包括二甲基三硫醚、癸醛、（E,Z）-2,6-壬二烯醛、3-甲基丁醛、壬醛、3-甲硫基丙醛、辛醛等物质。     

Identification of the key odorants in barley malt (caramalt) using GC/MS techniques and odour dilution analyses

Application of the aroma extract dilution analysis (AEDA) on a distillate prepared from ground caramalt kernels followed by identification experiments revealed 3-methylbutanal (malty), 1-octen-3-one (mushroom-like), methional (cooked potato), (E,E)-2,4-decadienal (fatty, waxy), vanillin (vanilla-like), 2- and 3-methylbutanoic acid (sweaty) and 4-hydroxy-2,5-dimethyl-3-(2H)-furanone (caramel-like) as the most odor-active compounds. Using static headspace/olfactometry, the very volatile odorants dimethyl sulfide (cooked vegetable-like) and 2-methylpropanal (malty) were identified as additional odorants contributing to the overall rye-bread crust-like odour of the caramalt.     

羊脂肪关键香气成分分析

采用溶剂辅助蒸发装置分离并结合气相色谱-质谱及气相色谱-嗅闻分析加热后羊脂肪的关键香气成分。结果表明：根据谱库检索、保留指数、标准品比对气相色谱-质谱鉴定出58 种化合物,其中含量较高的化合物（＞3 μg/kg）为2,3-丁二醇、乙酸、乙偶姻、丙酸、己酸、2-己醇等。采用稀释法/气相色谱-嗅闻分析检测到37 个气味活性区域,根据谱库检索、保留指数、气味特征和标准品比对,鉴定出37 种气味活性成分,其中风味稀释（flavor dilution,FD）因子较大（log2FD≥4）的化合物有(E,E)-2,4-庚二烯醛、(E)-2-壬烯醛、(E,E)-2,4-辛二烯醛、(E)-2-癸烯醛、(E,Z)-2,4-癸二烯醛、(E,E)-2,4-癸二烯醛、2-庚醇、三甲基吡嗪、4-甲基噻唑、3-甲硫基丙醛、5-甲基-二氢-2(3H)-呋喃酮、4-乙基苯酚,这些化合物是羊脂肪香气的关键成分。研究结果可为羊脂肪的开发利用及羊肉香精的研制提供一定参考。     

基于顶空气相离子迁移色谱对鸭肉腥味特征物质的鉴定

为探究鸭肉在60℃和90℃两种温度煮制后的腥味特征物质，以鸭胸、鸭腿及鸭锁骨为研究对象，基于顶空气相色谱-离子迁移谱（headspace-gas chromatography-ion mobility spectrometry,HS-GC-IMS）技术结合嗅闻评价、电子鼻测定及风味物质评价分析确定鸭肉腥味特征物质。结果表明，在两种温度处理下，90℃处理的各部位鸭肉腥味重于60℃，且不同处理组鸭肉样品的腥味特征具有一定差异，电子鼻分析结果也验证了不同处理组鸭肉样品气味存在一定差异。同时基于HS-GC-IMS技术共鉴定出61种挥发性物质，鉴定发现不同处理组鸭肉样本中挥发性物质种类基本一致，而相对含量存在部分差异。结合嗅闻评价结果与风味物质的相对气味活性值共筛选出12种腥味特征物质，分别为壬醛、辛醛、庚醛、癸醛、戊醛、己醛、(E)-2-辛烯醛、(E)-2-庚烯醛、2-甲基丁醛、3-甲基丁醛、2-庚酮和1-辛烯-3-醇，这些物质之间发生的交互作用对鸭肉腥味形成具有重要贡献，并且因种类和含量的不同使得两种温度处理的鸭肉样品各具特征腥味。     

Identification and Quantification of Impact Aroma Compounds in 4 Nonfloral Vitis vinifera Varieties Grapes

ABSTRACT:  The aroma compounds in grapes of Cabernet gernischt, Cabernet sauvignon, Cabernet franc, and Merlot have been studied by gas chromatography–olfactometry (GC–O). The GC–O study revealed the presence of 58 aroma compounds in which 53 odorants were identified. The most significant odor active volatiles in 4 grape berries were β-damascenone, hexanal, ( Z )-3-hexen-1-ol, ( E,Z )-2,6-nonadienal, β-ionone, and unknown (RI = 1612). The quantification of volatile aroma compounds in grapes was developed using headspace solid phase microextraction (HS–SPME) coupled with gas chromatography–mass spectrometry (GC–MS). The influences of SPME fiber, extracting temperature, and time on the extraction of volatile compounds in grape were investigated. The aroma compounds in 4 grapes were quantified. According to the odor activity values (OAVs), ( E,Z )-2,6-nonadienal (OAV from 334 to 777), β-damascenone (OAV 245–790), β-ionone (OAV 97–193), and acetic acid (OAV 7–165) had comparatively high OVA values.     

GC-MS/O结合香气活性值表征烧麦中关键香气成分及其贮存过程中的变化情况

为确定烧麦中的关键香气成分及其贮存过程中的变化情况,采用溶剂萃取结合溶剂辅助风味成分蒸发提取烧麦中的挥发性成分,所得提取物经气相色谱-嗅闻联用仪与气相色谱-质谱联用仪分析,共鉴定出50个香气活性成分。通过香气提取物稀释分析,测定香气活性成分的香气稀释因子,其中1-辛烯-3-醇、茴香脑、愈创木酚、2-戊基呋喃等具有最高的香气稀释因子（6 561）。采用内标标准曲线法对37个香气稀释因子不低于81的成分进行定量分析;根据定量结果和阈值,计算物质的香气活性值,其中21个香气活性成分的香气活性值不低于1,被确定为烧麦的关键香气成分。通过分析室温贮存0～13个月后烧麦中37个成分含量并计算其香气活性值,发现烧麦贮存过程中关键香气成分的数量不变,除酱油酮、己醛和4-乙烯基愈创木酚的含量下降外,烧麦中多数重要香气活性成分含量变化较小。