Volatile Components of Roasted Shrimp

The components of the strong and favorable aroma obtained from roasted shrimp were investigated. The aroma concentrate of roasted shrimp was isolated by combining the dichloromethane extract and carbon dioxide distillation methods. The concentrate was fractionated into acidic, basic and neutral fractions. Each fraction was analyzed by combined gas chromatography-mass spectrometry. Seventy-seven compounds were identified, among which isovaleric acid, alkyl pyrazines, isovaleramide, ketones and some sulfur-containing compounds were the main and characteristic constituents of the roasted shrimp aroma.

These constituents were compared with those of the volatiles of boiled shrimp, which was prepared by using simultaneous distillation and extraction methods in a modified Likens and Nickerson’s apparatus.     

Volatile Components of Roasted Almonds: Basic Fraction

Roasted almond volatiles were isolated by vacuum carbon dioxide distillation of acetone extracts and separated into basic and non-basic fractions. The basic fraction was analyzed by combination gas chromatography-mass spectrometry utilizing open tubular column. Seventeen pyrazines and 2-formyl pyrrole were identified by comparison of their mass spectra with reference spectra. Besides them, five compounds were tentatively identified by mass spectrometry.     

Flavor Components of Roasted Almond

Roasted almond volatiles were separated into basic, carbonyl and non-carbonyl fractions. Each fraction was analyzed by combination gas chromatography-mass spectrometry. Twenty-five compounds, in addition to eighteen known components, were identified. Many of the components identified were considered to contribute to the overall flavor. 2,5-Dimethyl-4- hydroxy-3(2H)-furanone, which was identified from methanol extract of roasted almond, seemed to make the largest contribution to the sweet aroma of roasted almond.     

Studies on Flavor Components of Roasted Barley

Basic compounds in the volatiles of roasted barley were analyzed by a gas chromatograph and a combination instrument of gas chromatograph-mass spectrometer. As major components, the following nitrogeneous aromatic compounds were identified: pyridine, 2-methylpyrazine, 2,5-dimethylpyrazine, 2-ethyl-5-methylpyrazine, 2,3,5-trimethylpyrazine and a dimethylethylpyrazine. Ammonia was also detected in the volatiles of roasted barley by an amino acid analyzer.

The formation of 2,5-dimethylpyrazine from pyruvaldehyde-amino acid model systems during roasting was shown, and the possible formation mechanism of pyrazines was presented.     

Studies on Flavor Components of Roasted Barley

From the volatiles of roasted barley or those formed during roasting of barley, furfural, 2-methylbutanal, 2-methylpropanal, 3-methylbutanal, 2,3-pentanedione, ethylglyoxal and pyruvaldehyde were isolated and identified as their mono- or bis-2,4-dinitrophenylhydrazones.

Removal of the carbonyl compounds from the volatiles resulted in a loss of the characteristic aroma of roasted barley.     

Analysis of Volatile Components in Rice Bran

Volatiles stripped from rice bran are analyzed by gas chromatography and thin-layer chromatography either directly or after converted into 2, 4-DNPH’s or 3, 5-DNB’s. Most of prominent peaks revealed by a direct gas chromatography of the volatiles condensates behave as alcohols against classification reagents and are identified as methanol, ethanol, n-propanol, sec-butanol, isobutanol, n-butanol, isopentanol, n-pentanol and n-hexanol, respectively. Ethanol and methanol, being major components in the condensates are also detected by thin-layer chromatography of their 3, 5-DNB’s. Carbonyls identified by a flash exchange gas chromatography of 2, 4-DNPH’s of the volatiles are ethanal, propanal, isobutanal, acetone, n-butanal, isopentanal, n-pentanal and n-hexanal. Thin-layer chromatography of 2, 4-DNPH’s reveals presence of ethanal, acetone, isopentanal or/and isobutanal and n-hexanal in the volatiles. The experimental data have been integrated to furnish a basis for extensive comparison with other rice products and by-products.     

桑椹挥发性成分的分析研究

对广东桑桑椹石油醚和乙酸乙酯提取物中的化学成分进行GC-MS分析。与WILEY谱库的标样质谱图进行比较,鉴定出21种化学成分。     

生姜的挥发性化学成分

用ＧＣ／ＭＳ方法,定性定量地分析了用３种不同方法提取的姜油的化学成分,分别鉴定了４６,５０,６１个化合物。蒸馏油主要含有单萜、倍半萜烯类化合物,未见生姜特有的辣味成分。冷榨油和超临界ＣＯ２萃取油除倍半萜类化合物外,主要含有辣味成分,含量分别为１８．６１％,２３．０９％。冷榨油及超临界ＣＯ２萃取油较好地保持了生姜的特征辛香气及辣味成分     

南瓜5个品种果肉的挥发性成分分析

为了解南瓜（Cucurbita sp.）果实中的特征风味物质,采用顶空固相微萃取气质联用（HS-SPME-GC-MS）技术对5个品种（‘新美玉’、宝丰’、‘金磨盘’、‘健宝’和‘东升’）果肉的挥发性成分和含量进行测定并进行主成分分析。结果表明,从5个品种南瓜果肉中共检测出68种挥发性成分,以醇类、醛类和烃类为主,其中壬醛、正己醛、反,反-2,4-庚二烯醛、顺-壬-3-烯-1-醇和正己醇等化合物为南瓜果肉的主要风味物质。主成分分析表明,南瓜5个品种果肉的风味差异化合物主要有9种,其中十一醛和反-2-壬烯醛为‘健宝’和‘东升’的特征风味物质;1,9-壬二醇是‘宝丰’的标志性风味物质;‘金磨盘’和‘新美玉’因3-壬炔-1-醇相对含量较高而区别于其他品种。因此,特征挥发性物质为南瓜品种改良和品质评价提供参考。     

Major Volatile Components Formed from Casein during Roasting

The volatiles, produced from casein during roasting at 250°C for 1 hr, were fractionated and analyzed by various methods including the combination of gas chromatography and mass spectrometry. The following kinds of compounds were tentatively or conclusively identified: six aliphatic aldehydes, benzaldehyde, acetophenone, hydrogen sulfide, methanethiol, dimethyl disulfide, five primary alkylamines, piperidine, N-ethylcyclohexylamine, two alkylpyrazines, ethylmethylpyridine, three aliphatic carboxylic acids, pyruvic acid, benzoic acid, six aliphatic alcohols, and three aromatic hydrocarbons. α-Dicarbonyls were not formed in any detectable amount.

The results obtained above are discussed in comparison with those of pyrolysis of some kinds of α-amino acid and also with those of some roasted foods.     

Volatile Flavor Components of Kumazasa (Sasa albo-marginata)

The volatile flavor components of Kumazasa (Sasa albo-marginata) were studied by headspace and steam distillation analyses. Thirty nine and 90 components were identified in the headspace and steam distillation concentrate respectively by GC and GC-MS. The identified components include 7 hydrocarbons, 23 alcohols, 14 aldehydes, 8 ketones, 17 phenols and 14 acids.

The components which are believed to contribute to the characteristic flavor of Kumazasa are deduced to be: 1-penten-3-ol, trans-2-hexenal, 1-hexanol, cis-3-hexen-1-ol, cyclohexanol, α-ter-pineol, 4-octanolide and β-ionone.     

Volatile Flavor Components of Watermelon (Citrullus vulgaris)

Volatile flavor components of watermelon fruit (Citrullus vulgaris) were obtained by distilling juice under reduced pressure and extracting the resulting distillate with Freon-11. The volatiles were separated into acidic and neutral fractions and then analyzed by gas chromatography and gas chromatography-mass spectrometry.

Fifty-two compounds were found for the first time as flavor components of watermelon. Among them, the following compounds have not been previously reported as naturally occurring flavor components: 4-oxononanal and 2-hydroxy-, 2-pentyloxy-, 2-hexyloxy-, 2-octyloxy-, 2-nonyloxy-, 2-[(Z)-3-noneyloxy]-, 2-[(Z)-2-nonenyloxy]-, 2-[(Z,Z)-3,6-nonadienyloxy]-, 2-benzyl-oxy-, and 2-phenetyloxy-5-pentyltetrahydrofurans.     

光叶三角梅'Formosa'叶片挥发性组分的GC-MS分析

三角梅不仅观赏性强,而且具有多方面的保健作用。为了阐明三角梅的次生代谢机制,本研究采用水蒸气蒸馏法提取光叶三角梅（Bougainvillea glabra‘Formosa’）叶的挥发性成分,并通过GC-MS法进行定性和定量分析。本试验共分离出61种成分,经NIST数据库检索、与标准谱图比较,鉴定出47个化学组分,占总挥发性组分含量的90％以上。结果表明,该三角梅叶中舍有叶醛、植醇、棕榈酸,对乙烯基愈创木酚、柠檬烯等对人体有益的化合物。     

顶空进样气相色谱-质谱联用法分析木棉花挥发性成分

为研究木棉Bombax ceiba 鲜花的挥发性成分,采用顶空固相微萃取-气相色谱-质谱联用法(HS-SPME-GC-MS)进行鉴定分析。通过GC-MS,采用面积归一法从木棉花中鉴定了56 个主要组分及其相对含量。结果表明,主要组分为模菲(13.74%)、(1R,3aS,5aS,8aR)-1,3a,4,5a 四甲基-1,2,3,3a,5a,6,7,8-八氢环戊二烯并[c]环戊二烯(10.95%)、2-亚甲基-4,8,8-三甲基-4-乙烯基-双环[5.2.0]壬烷(10.36%)等。其中萜烯类化合物占55.24%,烷类化合物占29.72%,还有少量的醛类、酮类和酯类化合物。     

GC-MS分析甜菊叶的挥发性成分

甜菊(Stevia rebaudianum Bertohi)叶经固相微萃取(SPME)和同时蒸馏萃取(SDE),用气相色谱/质谱法(GC-MS)检测其挥发性成分.从甜菊叶中共检出101种化学物质,其中从SPME萃取物中检出67种,SDE萃取物中检出80种,二者共有组分46种.主要成分为反式-α-香柠檬烯、β-蒎烯、石竹烯氧化物、匙叶桉油烯醇、橙花叔醇等,其主要成分与菊科(Compositac)其他植物的明显不同.     

紫锥菊挥发性成分分析研究

采用气-质(GC-MS)联用技术结合顶空固相微萃取(HS-SPME)与传统共水蒸馏法,对紫锥菊植物干花与干根中挥发性成分进行分析方法研究。GC-MS(配N ist2005标准质谱库)从传统方法提取的紫锥菊干根挥发油中分离分析出188个峰,初步鉴定出68种化合物,从聚二甲基硅氧烷(PDMS 7,100μm)及聚丙烯酸酯(PA 85μm)三种固相微萃取涂层吸附的紫锥菊干花挥发性成分中分别分离分析出27、118、105个峰,各自鉴定出1、22、23种化合物。对不同处理方法及紫锥菊植物不同部位所得数据进行了相识性与差异性的比较,所建分析方法及所得结果为了解紫锥菊植物体挥发性有效成分提供了参考。     

GC-MS法分析曼陀罗挥发油的化学成分

用水蒸气蒸馏法从曼陀罗中提取挥发油,并用气相色谱/质谱联用技术(GC-MS)对挥发油的化学成分进行分离鉴定,用气相色谱峰面积归一化法确定各组分的相对含量.结果从曼陀罗挥发油中鉴定出58种化合物,占总挥发油量的92.37%.其中主要成分为5,6-二氢-6-戊基-2H-吡喃-2-酮(44.29%)、二苯胺(12.50%)、四十四烷(10.41%)、二十烷(4.19%)、(E)-3-己烯-1-醇(2.38%)、3,7,11,15-四甲基-2-十六碳烯-1-醇(2.28%)等.     

华北落叶松枝叶挥发性成分

利用水蒸气蒸馏法提取华北落叶松枝叶的挥发油,进一步采用气相色谱-质谱联用方法对其化学成分进行分析,共分离鉴定出79种化学成分,主要有大根香叶烯（11．35％）、1-异丙基4,7．二甲基-1,2,4a,5,8,8a-六氢萘酚（6．53％）、石竹烯（5．84％）、长叶松节烷（5．23％）、7-甲基4-亚甲基-1-（1-甲基乙基）-1,2,3,4,4a,5,6,8a-八氢萘（5．21％）、（E）-3,7,11-三甲基-1,6,10-十二烷三烯-3-醇（5．17％）、．tau．-muurolol（4．55％）、α-杜松醇（4．31％）、α-石竹烯（4．22％）等,其中萜烯类及其含氧衍生物占较大比例。