Selection of a representative extraction method for the analysis of odourant volatile composition of French cider by GC-MS-O and GC × GC-TOF-MS

The experimental conditions of a representative odour extraction method were determined after testing eight SPME, dynamic headspace and purge-and-trap procedures. Headspace SPME with a Car/PDMS fibre was evidenced to be the most suitable method to obtain representative extract of cider odour. This method was applied to extract the volatile compounds of two French ciders and gas chromatography-mass spectrometry-olfactometry (GC-MS-O) was used to analyse the odourant profile and the aroma-active compounds of these ciders. Thirty-six odourant zones were perceived in one cider and 24 in the other. Comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry was used to identify odour-active compounds which were undetermined after the first chromatographic separation. Ethyl 2-methylbutanoate, 2-phenylethanol, ethyl butanoate, ethyl 2-methylpropanoate, ethyl hexanoate, oct-1-en-3-one, 2-phenylethyl acetate, ethyl dodecanoate, 3-methyl-1-butanol and 2-methylbutanoic acid were among the most potent odourants in both ciders, as well as oct-1-en-3-one, which could be identified only by comprehensive GC. Thanks to the association of the two methods, 80% of the aroma-active compounds were identified, some of them being present at trace levels in ciders.     

四种食用菊花主要成分分析

采用滴定法、紫外分光光度法、高效液相色谱法对4种食用菊花SYJ1、SYJ2、SYJ3和SYJ4主要化学成分(氨基酸、可溶性糖、可溶性蛋白、总黄酮、抗坏血酸、绿原酸、槲皮素和黄芩苷)进行含量测定。采用水蒸气蒸馏法提取食用菊花中的挥发油,用气相色谱-质谱法对其挥发油化学成分进行鉴定,并用峰面积归一化法测其相对含量。结果表明:食用菊SYJ3中主要化学成分含量较高,其氨基酸、可溶性糖、可溶性蛋白、总黄酮、抗坏血酸、绿原酸、槲皮素和黄芩苷含量分别为15.69、65.03、39.72、156.97、69.95、1.96、3.13和17.62 mg·g-1。4种食用菊花挥发油成分数量分别为37个、33个、25个和38个,最主要成分为α-蒎烯、1,8-桉叶油素、双环(2.2.2)癸烷-2-烯-5-酮、2,6,6-三甲基-双环(3.1.1)-庚-2-烯-4-醇-乙酯、β-榄香烯、(-)-β-石竹烯和α-荜澄茄烯。不同品种食用菊花主要化学成分含量及挥发油种类和含量差异显著(p<0.05)。     

HS-SPME-GC-MS结合HPLC分析5种食用菌鲜品中的风味成分

挥发性香气成分和非挥发性滋味成分是食用菌品质的重要指标,为探究平菇、香菇、双孢蘑菇、金针菇和杏鲍菇等5种食用菌鲜品中的风味成分,采用顶空固相微萃取结合气相色谱-质谱联用(HS-SPME-GC-MS)、高效液相色谱(HPLC)等方法对5种食用菌鲜品中的风味物质进行分析,通过相对气味活度值(Relative odor activity value,ROAV)研究了不同组分对整体风味的贡献,并测定了5种食用菌的总游离氨基酸和5'-核苷酸的含量。结果显示:5种食用菌中共鉴定出35种挥发性化合物,包括醛类5种、酮类5种、醇类9种、烷烃类8种、杂环和硫化物6种、酯类1种和含氮化合物1种;其中共有成分8种,分别为苯甲醛、3-辛酮、1-辛烯-3-酮、3-辛醇、2-乙基己醇、5-甲基-2-乙酰基呋喃、2-戊基呋喃和甲氧基苯肟。平菇鲜品中主体挥发性香气成分(ROAV≥1)为1-辛烯-3-酮、1-辛烯-3-醇和3-辛酮;香菇鲜品中主体挥发性香气成分为二甲基二硫醚、二甲基三硫醚、1-辛烯-3-酮和甲硫醇;双孢蘑菇和金针菇鲜品中主体挥发性香气成分为1-辛烯-3-酮、3-辛酮和3-辛醇;而杏鲍菇鲜品中的主体挥发性香气成分是1-辛烯-3-酮和1-辛烯-3-醇。5种食用菌中总游离氨基酸含量为2.72~3.65 mg/g,总呈味核苷酸含量为154.40~1013.60 μg/g,不同品种间总游离氨基酸和呈味核苷酸含量差别较大。本研究有助于深入了解食用菌风味特征,对食用菌品种的改良、定向培育及食用菌的加工应用具有指导作用。     

Human olfactory responses to 5-alpha-androst-16-en-3-one--principal component of boar taint

Analysis of the olfactory responses of men and women to a pure sample of 5α-androst-16-en-3-one showed that 7·6% of women were unable to detect the odour compared with 44·3% of men. For subjects able to detect the odour, there was a highly significant difference between sexes in the hedonic scores, but not in the individual threshold values. Women found the odour significantly more unpleasant than did men, and the relevance of this result to the meat industry is discussed.     

14 种侧耳属食用菌干品挥发性香味成分分析

挥发性香味成分是影响食用菌品质的重要指标。为探究不同侧耳属食用菌挥发性香味物质的组成和相对含量,采用顶空固相微萃取结合气相色谱-质谱联用方法对14 种侧耳属食用菌干品中的挥发性香味物质进行分析,并通过相对气味活度值（relative odor activity value,ROAV）和共有成分分析研究不同组分对整体风味的贡献。结果显示：14?种侧耳属食用菌干品中共鉴定出41?种挥发性化合物,主要包括醛类、醇类、酮类、酯类、羧酸类和呋喃类等;其中共有成分8?种,分别为正己醛、2-丁基-2-辛烯醛、1-己醇、1-辛烯-3-醇、正辛醇、2-辛烯-1-醇、3-辛酮和1-辛烯-3-酮;此外,醇类化合物在14?种侧耳属食用菌中相对含量远高于其他类化合物。除佛罗里达侧耳PF6中主体挥发性香气成分为1-辛烯-3-酮、1-辛烯-3-醇和正辛醛外,其他13?种侧耳属食用菌中主体挥发性香气成分均为1-辛烯-3-酮和1-辛烯-3-醇。共有香气物质主成分分析显示前3?个主成分方差累计贡献率达到83.627%,主要代表性成分为1-己醇、正己醛、2-丁基-2-辛烯醛、正辛醇、2-辛烯-1-醇、1-辛烯-3-酮和3-辛酮等,它们是影响食用菌风味的关键性香味成分。     

Study of the aroma compounds of rose apple (<Emphasis Type="Italic">Syzygium jambos</Emphasis> Alston) fruit from Brazil

Volatiles of the headspace and total aqueous extract from the rose apple fruit were investigated by gas chromatography (GC)–flame ionization detection, GC–mass spectrometry and GC–olfactometry/aroma extract dilution analysis O/AEDA). The headspace fraction was rich in low boiling compounds, while medium and high volatility components predominated in the total aqueous extract. GC–O/AEDA revealed that hexanal, 3-penten-2-one, hexanol, (Z)-3-hexen-1-ol, linalool, isovaleric acid, benzyl alcohol, 2-phenylethylalcohol and (E)-cinnamaldehyde were potent odorants contributing to the headspace aroma. Thus, they might be related to the first odour impression of the fruit. Other potent volatiles, such as caproic and phenylacetic acids, methyl-(E)-cinnamate and (E)-cinnamyl alcohol were identified in the total aqueous extract, only. These results indicated that some volatiles, with medium and high boiling points, might also contribute to the overall rose apple flavour. Besides them, volatiles with lower odour potency, such as 7-octen-4-ol, acetic acid, 2-octen-1-ol and cinnamic acid, could have some additional effect for the overall fruit aroma.     

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.     

Synthesis and analysis of l-octen-3-ol,the main flavour component of mushrooms

The most abundant volatile occurring in mushrooms and responsible for the mushroom odour is 1-octen-3-ol. To meet the demand for a flavour compound yielding a mushroom odour a study was carried out on the possibility of obtaining l-octen-3-ol synthetically. On the basis of literature data and experiments performed the synthesis of this compound was carried out by two methods, i.e. by GRIGNARD reaction between acrolein and amyl iodide and by selective reduction of l-octen-3-on. The purity of the l-octen-3-ol obtained was determined by GLC chromatography and by spectroscopic methods. The compound obtained by GRIGNARD reaction had its IR, ¹³C NMR spectra and GLC chromatogram identical with those of the standard. The yield of 1 -octen-3-ol by GRIGNARD reaction was 65 %, while the reduction of the ketone to the alcohol gave a yield of 90%.     

Volatile compounds from the fruiting bodies of three Hygrophorus mushroom species from Northern Greece

The volatile composition of the wild edible mushroom species Hygrophorus chrysodon , Hygrophorus eburneus and Hygrophorus russocoriaceus was analysed by headspace-solid phase microextraction combined with gas chromatography–mass spectrometry. Forty-five volatile compounds were detected, including alcohols, aldehydes, ketones, hydrocarbons, esters and terpenes. The most abundant compounds in the three species were 3-methyl butanal, hexanal, p -cymene, 3-octanone, 1-octen-3-one, 3-octanol, 1-octen-3-ol and benzoic acid methyl ester. The concentration of eight-carbon (C₈) compounds relative to the total volatiles varied widely ranging from 24.14% to 61.41% among the three species. Finally, the presence of sesquiterpenes only in Hygrophorus russocoriaceus , confirms the characteristic distinctive cedar odour of this species.     

Relationship between odour-active compounds and flavour perception in meat from lambs fed different diets

To identify the most important aroma compounds in 20 d-aged meat from castrated heavy Corriedale lambs fed one of four diets, grilled loin samples were subjected to a dynamic headspace-solid phase extraction (DHS-SPE) and gas chromatography–olfactometry (GC–O). Most of the important odorants were aldehydes and ketones. To evaluate the effect of finishing diet on carbonyl compounds, a derivatization of the headspace carbonyls using o-[(2,3,4,5,6-pentafluorophenyl)methyl]hydroxylamine hydrochloride (PFBHA) and analysis by GC–MS was conducted. Diet did not affect aliphatic saturated aldehydes. The meat from lambs finished on pastures, without a concentrate supplement, had very low concentrations of lipid-derived unsaturated aldehydes and ketones and Strecker aldehydes, possibly because of the protective effect of antioxidants that occur in the diet naturally. Lamb flavour was related to the concentration of heptan-2-one and oct-1-en-3-one, but rancid or undesirable flavours were not related to the abundance of carbonyl compounds.     

黄牛肝菌中挥发性成分的GC-MS分析

利用顶空GC-MS技术对黄牛肝菌干品和蒸馏萃取得到的黄牛肝菌馏分中的挥发性成分进行了分析。从黄牛肝菌干品中鉴定出59种挥发性成分,占色谱流出峰总面积的相对质量分数为61.42%,主要为杂环类、酸类、酮类和酯类,主要成分有:戊酸、2,6-二甲基吡嗪、1-乙基-2-甲酰基吡咯、苯乙酮、苯甲醛、2,5-二甲基吡嗪、丙位戊内酯、2-乙基-(5或6)-甲基吡嗪和乙醇。从黄牛肝菌馏分中鉴定出46种挥发性成分,占色谱流出峰总面积的相对质量分数为55.25%,主要为酮类、醛类、酯类和醇类,主要成分有:苯乙酸甲酯、苯甲醛、1-辛烯-3-酮、1-辛烯-3-醇、苯乙酮、环辛醇和2-辛烯醛。微量芳香含硫化合物在黄牛肝菌馏分中有检出。样品在两种处理方式下鉴定得到16种相同组分,主要成分相对质量分数有显著差异。研究发现,干品分析得到的挥发性组分种类较馏分组分丰富,但蒸馏萃取对挥发性组分含量有富集作用。     

不同类型发花砖茶特征香气成分研究

采用感官审评方法、固相微萃取/气相色谱-质谱联用技术、香气活性值(odor activity value,OAV)法结合化学计量学方法,分析茯砖茶、发花白茶砖及发花红茶砖特征香气成分。结果表明,从感官上,3种发花砖茶均有典型"菌花香",但茯砖茶菌花香中带木香,且略带泥土气,发花白茶砖菌花香中带清香,发花红茶砖菌花香中带花香、甜香。3种发花砖茶中共检测出75种挥发性成分,以醛类、醇类、酮类及碳氢化合物为主,其中27种挥发性成分为呈香物质。基于OAV值和偏最小二乘判别分析,鉴定了3种发花砖茶中15种特征香气成分。其中,茯砖茶以具有青气和木香属性的己醛、壬醛、(E,E)-2,4-壬二烯醛、(E,E)-2,4-庚二烯醛、2-正戊基呋喃、3,5-辛二烯-2-酮、甲基庚烯酮、β-紫罗兰酮和氧化芳樟醇Ⅰ为特征香气成分;发花白茶砖以具有清香属性的苯乙醛为特征香气成分;发花红茶砖以具有蘑菇香、泥土气属性的1-辛烯-3-醇,具有花香属性的樟醇、芳樟醇和水杨酸甲酯以及甜木香的雪松醇为特征香气成分。     

Acidic components of boar preputial fluid

Several acids present in the acidic fraction of boar preputial fluid have been identified by gas chromatography. They are acetic, propionic, n-butyric, isobutyric, n-valeric, isovaleric, α- and β-methylvaleric, caproic, n-nonanoic and n-undecanoic acids. Unsaturated aliphatic acids include pent-4-enoic, pent-2-enoic, hept-2-enoic and oct-2-enoic acids. Benzoic, phenylacetic and β-phenylpropionic acids were also identified. Several peaks remained unidentified. Quantitative data for the major components (aromatic acids and acetic acid) are presented and also for the C₃ to C₅ saturated aliphatic acids which are known to have unpleasant odours and low thresholds of detection. The contribution of these compounds to the odour of a boar is discussed, but it is concluded that they contribute little to the taint of heated boar fat.     

Volatile Components of Mushroom (Agaricus subrufecens)

Volatile components of mushroom (Agaricus subrufecens) were extracted by the simultaneous distillation-extraction method. About 30 volatile components could be identified by GC and GC-MS analyses. Aromatic compounds, such as benzyl alcohol, benzaldehyde, benzonitrile, methyl benzoate, and a phenyl acetic acid-like compound, were the major volatiles (>85%) and are possibly the cause of “almond-like” aroma of this mushroom. Eight carbon compounds which are common to most mushroom volatiles make up only a minor part (ca 2%) of the total volatiles.     

Odor thresholds of the C(19)-Δ(16)-steroids responsible for boar odor in pork

Odor thresholds for each of the five C(19)-Δ(16)-steroids believed to contribute to boar odor in pork were determined using duo-trio test methodology. Threshold values for 5,16-androstadien-3β-ol (I) and 4,16-androstadien-3-one (II) were approximately 10 μg/g, whereas those for 5α-androst-16-en-3-one (III), 5α-androst-16-en-3α-ol (IV) and 5α-androst-16-en-3β-ol (V) were about 1 μg/g. Statistical comparisons of the mean threshold values for each of these compounds showed no difference (P < 0·05) among the mean thresholds of III, IV and V or between compounds I and II. The mean thresholds of compounds I and II were different (P < 0·05) from those of compounds III, IV and V. Triangle test methodology was employed to measure the ability of trained panelists to differentiate the odors of each of these five compounds either singly or in all combinations. Results showed that panelists were able to differentiate (P < 0·05) between the odors of the C(19)-Δ(16)-steroids possessing ketone groups (II and III) and those containing alcohol groups (I, IV and V). Panelists were not able, however, to differentiate (P < 0·05) between the odors of the three alcoholic steroids (I, IV and V), nor were they able to differentiate between the odors of the two ketonic steroids (II and III).     

Flavour profiling by gas chromatography–mass spectrometry and sensory analysis of yoghurt derived from ultrasonicated and homogenised milk

The odour, flavour, taste, sensory and volatile components profile of yoghurt, derived from milk homogenised by ultrasound or pressure were compared. The ultrasonication of milk led to yoghurts with lower degree of likeness (DOL) and off-flavours compared with those of yoghurts from pressure treated milk; also, burned, pungent and fatty flavour characteristics were more intense. The volatile components were identified by solid phase microextraction–gas chromatography–mass spectrometry (SPME–GC–MS). Both homogenisation treatments lead to chromatograms with similar peak areas of 2,3-butadione, 3-hydroxy-2-butanone, delta-decalactone, while the chromatogram peak areas of acetone, 2-butanone, 2-heptanone, bicyclo[2,2,1]-heptan-2-one, 2-nonanone, 2-undecanone, butanoic acid, hexanoic acid, octanoic acid, n-decanoic acid, hexadecanoic acid, acetaldehyde, hexanal, 1-buten-3-yne, heptane and dimethylsulphide were higher for the ultrasonicated samples. Sensory characteristics and GC–MS profiles were correlated with DOL and two models created with PLS regression. Both models included the appropriate variables and showed adequate ability to describe DOL by sensory characteristics or volatile components.     

Influence of pig crossbreed on the composition, volatile compound content and flavour of dry cured ham

The extraction of volatile compounds from dry-cured ham using a dynamic head-space method coupled with gas chromatography mass-spectrometry (GC-MS) enabled the identification of a large number of components. Some of these compounds exhibited intense sensory characteristics during odour assessment. Using similar technology, the effect of pig crossbreeds: Landrace × Large-White, Duroc × Gascon-Meishan, Piétrain × Gascon-Meishan and Large-White × Gascon-Meishan, on both volatiles and the flavour of dry-cured hams was limited, although differences were observed in aromatic compounds like 1-octen-3-ol (mushroom), 2,3-butanedione and acetoin (butter like).     

不同产地红茶香气品质的SPME/GC-MS分析

为了探究云南、福建、宜昌三地红茶香气的物质基础及其主要呈香特征,本试验采用感官审评方法及顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用技术（GC-MS）,对不同产地红茶的挥发性香气成分进行了比较分析。结果表明:在感官上,6种红茶均是以甜香为主,其中滇红茶甜香浓郁,福鼎红茶花香与甜香兼具,宜昌红茶则是甜香纯正。利用气质联用技术检测,在6种红茶中共分离鉴定出67种香气化合物,包含醇类、醛类、酮类、酯类、烯烃类、烷烃类、酸类等,主体香气成分包括芳樟醇及其氧化物、2,2,6-三甲基-6-乙烯基四氢-2H-呋喃-3-醇、橙花叔醇、β-紫罗酮、香叶基丙酮、水杨酸甲酯等;其中,滇红茶中以芳樟醇及其氧化物为特征香气成分;福鼎红茶中以β-二氢紫罗兰酮、β-柏木烯为特征性香气成分,宜昌红茶则以香叶醇、棕榈酸为特征性香气成分。该研究从香气组分的角度明确了不同产地红茶香气品质形成的化学物质基础,为红茶品质提升及产地鉴别提供理论依据。