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。     

Static Headspace and Aroma Extract Dilution Analysis of Parmigiano Reggiano Cheese

ABSTRACT The aroma compounds in Parmigiano Reggiano cheese were studied with Aroma Extract Dilution Analysis (AEDA). Both static headspace and solvent extraction, high-vacuum distillation techniques were used to isolate aroma compounds. Thirty-six odor-active compounds had high flavor dilution values. Static headspace gas chromatography/olfactometry (GC/O) analysis found that acetaldehyde, 2-methylpropanal, 2-methylbutanal, 3-methylbutanal, ethyl butanoaic, and ethyl hexanoate had low detection volumes, while high-vacuum distillation revealed that acetic, butanoic, hexanoic, octanoic, and decanoic acids, and ethyl butanoate, ethyl hexanoate, dimethyl trisulfide, methional, and phenylacetaldehyde had high flavor dilution values. In addition, some pyrazines appear to be important to the aroma of this cheese.     

基于OAV和AEDA对工夫红茶的PLSR分析

采用顶空蒸汽蒸馏提取结合气相色谱-质谱联用技术及气相色谱-嗅闻技术,对4?种中国工夫红茶进行定性、定量分析。根据香气成分的香气活力值和芳香萃取物稀释分析分别筛选出30、36?种挥发性成分作为香气成分,结合2?种方法确定22?种香气成分为工夫红茶的香气关键成分,并将其与感官属性和红茶样品进行偏最小二乘法相关性分析。确定对工夫红茶香气起重要作用的22?种关键香气物质为：1-戊醇、叶醇、1-辛烯-3-醇、反式氧化芳樟醇、芳樟醇、顺-6-壬烯醇、香叶醇、苯甲醇、苯乙醇、橙花叔醇、戊醛、己醛、反-2-己烯醛、糠醛、（反,反）-2,4-庚二烯醛、苯乙醛、（反,反）-2,4-癸二烯醛、水杨酸甲酯、丙位-壬内酯、2,3-丁二酮、2-庚酮和香豆素。     

棘托竹荪蛋中的挥发性成分分析研究

采用同时蒸馏萃取法（SDE）结合气质联用仪（GC-MS）对棘托竹荪蛋的挥发性成分进行分析,同时采用芳香萃取物稀释法（AEDA）结合嗅闻仪（GC-O）对其挥发性成分进行了鉴定。研究结果表明通过GC-MS从棘托竹荪蛋中共鉴定出97种挥发性成分,其中包括18种醛、13种酮、11种醇、8种呋喃类化合物、6种含氮化合物、2种含硫化合物、3种酚、4种酯、3种大环化合物、21种酸、7种烃和1种醚;采用GC-O鉴定出12种稀释系数（FD）在1～27之间的活性香成分,包括3-甲基丁醛（FD27,0.88mg/kg,果香、似巧克力的香气）、己醛（FD27,13.41mg/kg,青香）、1-辛烯-3-酮（FD27,3.01mg/kg,蘑菇香）、糠醛（FD27,62.16mg/kg,甜香,烤香）、5-甲基糠醛（FD27,25.55mg/kg,焦糖香）、2,4-癸二烯醛（FD27,1.83mg/kg,青香,甜香,似柑橘香）等。可以为进一步开发、研究竹荪功能性食品,以及对竹荪进行安全性评价等提供基础数据和理论依据。     

Evaluation of fat-derived aroma compounds in blue cheese by dynamic headspace GC/Olfactometry-MS

The aroma compounds in Blue cheese were studied with a dynamic headspace-GC/olfactometry (GC/O-DH) technique and evaluated by both aroma extract dilution analysis (AEDA) and the Osme technique to identify and assign importance to aroma compounds. AEDA aroma dilution values were obtained by sequential reduction of sample size, and Osme values were obtained based on aroma intensity and duration. The most important compounds contributing to Blue cheese aroma were diacetyl, 2-methylpropanal, 3-methylbutanal, ethyl butanoate, ethyl hexanoate, methional, dimethyl trisulfide, 2-heptanone, and 2-nonanone. Compounds central to the characteristic Blue cheese aroma and typically derived from milkfat included 2-heptanone, 2-nonanone, butanoic acid, hexanoic acid, and ethyl esters. Since the methyl ketones contributed the characteristic Blue cheese aroma, a flavor concentrate enriched in methyl ketones to impart characteristic Blue cheese aroma was synthesized using Penicillium roqueforti spores in a model system. A fivefold enhancement in methyl ketone production was obtained by providing aerobic conditions. The addition of sucrose and serine, compounds known to affect mold spore metabolism, did not enhance methyl ketone production but caused generation of an uncharacteristic fruity, floral aroma.     

Potent odorants in "Smen", a traditional fermented butter product

 Potent odorants in a sample of traditional Moroccan smen were characterized by an aroma extract dilution analysis. In the acidic fraction, butanoic acid followed by hexanoic acid showed the highest flavor dilution (FD)-factors. Further quantitative determination of both acids in the same sample revealed high concentrations, in the g/kg level. In contrast, the low FD-factors found for the volatiles detected in the neutral fraction suggest that they contribute little to overall flavor. Butanoic and hexanoic acids are likely the key odorants of smen flavor, which is consistent with lipolysis being the primary mechanism of aroma development in the product. Received: 24 January 2000 / Revised: 8 June 2000     

Identification of the odour-active cyclic diketone cis-2,6-dimethyl-1,4-cyclohexanedione in roasted Arabica coffee brew

We investigated odour-active trace compounds in roasted Brazilian Arabica coffee. Aroma dilution extract analysis (AEDA) applied to the volatile oil extracted from roasted coffee brew revealed 34 odour-active compounds. Among these, a pungent-smelling unknown odour-active compound was determined. The volatile oil was fractioned by silica gel column chromatography. Gas chromatography–olfactometry (GC–O) and multidimensional gas chromatography–mass spectrometry (MDGC–MS) of the fraction which contained a significant amount of the target unknown compound revealed the cyclic 1,4-diketone, cis-2,6-dimethyl-1,4-cyclohexanedione, which had a pungent odour, and was thus first identified in roasted coffee. Model experiments revealed that cis-2,6-dimethyl-1,4-cyclohexanedione was formed via thermal degradation of sugars, especially monosaccharides, under alkaline conditions. Further, we demonstrated that 2-hydroxy-3-pentanone and 1-hydroxy-2-propanone, thermal degradation products of monosaccharides, were closely related to the formation of cis-2,6-dimethyl-1,4-cyclohexanedione.     

Identification of impact odorants of young red wines made with Merlot,Cabernet Sauvignon and Grenache grape varieties: a comparative study

An Aroma Extract Dilution Analysis (AEDA) has been carried out on three monovarietal young red wines plus a mixture of wines aged one year. The aromograms contain 85 odour-active regions classified in four categories of intensity. The 11 most powerful odorants, 14 out of the 17 second-most powerful, and 34 of the rest could be identified using a HPLC prefractionation method and standard HRGC-MS-olfactometric techniques. The most active odorants of the monovarietal wines were isoamyl and β-phenylethyl alcohols, the ethyl esters of butyric, isobutyric, 2-methyl butyric and hexanoic acids, γ-nonalactone and eugenol. Some others worth mentioning are ethyl isovalerate, isoamyl acetate, hexanol, c-3-hexenol, linalool, geraniol, guaiacol, ethyl cinnamate, ethyl dihydrocinnamate, β-damascenone, δ-decalactone and wine lactone. Compounds with less aromatic intensity but also present in some of the wines were sotolon, isopropyl- and isobutylmethoxypyrazines and 4-mercapto-4-methylpentan-2-one. Data show that there are no impact compounds characteristic of only one variety, and that differences between varieties are quantitative rather than qualitative. © 1999 Society of Chemical Industry