Simultaneous Steam Research Articles

Comparison of volatile components in fermented soybean pastes using simultaneous distillation and extraction (SDE) with sensory characterisation

In this study, the volatile compounds in nine fermented soybean pastes were extracted and analysed by simultaneous steam distillation and extraction (SDE) and gas chromatography–mass spectrometry (GC–MS), respectively. A total of 91 volatile components were identified. The differences in volatiles were observed by applying principal component analyses (PCA) to GC–MS data sets. Most of the samples did not show apparent groupings; however, a three sample clustering (CJW, SIN and HAE) was observed for pastes made by Aspergillus oryzae inoculation. From the PCA of the sensory data, samples are primarily separated along the first PC (explained 68% of the total variance), between samples like SUJA, CHJA and SOHI with high intensities of ‘briny’, ‘soy sauce’, ‘musty’ and ‘astringent’ and the samples (CJW and SIN) with intense levels in ‘sweet-grain’, ‘sweet’ and ‘MSG’ attributes. The individual concentrations of volatile compounds such as isoamyl acetate, furfuryl alcohol, maltol, pyrazines, 1-octen-3-ol and 2-methoxy-4-vinyl phenol corresponded well to the intensities of related sensory attributes by the correlation analysis.

Volatile Compounds Collected by Simultaneous Steam Distillation-Solvent Extraction from Hong Kong Salt-Dried Croakers

We compared the quality and quantity of volatile components in salt-dried croakers prepared by different methods and obtained from different locations. In total, 110 compounds were found among regular- and delay-type salt-dried croakers purchased from two locations in Hong Kong. The major chemical classes included miscellaneous compounds(17), pyrazines(16), alcohols(15), and sulfur-containing compounds(13). Fish obtained in different locations but prepared by the same method differed only slightly in the number of identified compounds. In general, fish prepared by the delay method had a larger number of compounds compared to fish prepared by the regular method. Further, a greater number and higher levels of compounds were found in the fish obtained from one of the two locations. Overall, the delay preparation method resulted in a greater number of compounds with stronger intensity compared to the regular method.

Antioxidant Activities of Aroma Extracts in Commercially Available Red Wines in Korea

The antioxidant activities of aroma extracts from commercially available red wines in Korea were evaluated. The aroma extracts of the red wines were extracted by simultaneous steam distillation. Antioxidant activity was measured by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and ABTS (2,2-azino-bis-3-ethylbenzothiazoline- 6-sulphonic acid) radical cation scavenging activity. DPPH radical scavenging activity of the aroma extracts in the red wines increased with increases in the amount of wine used for aroma extraction. Antioxidant activities of domestic wine 1, imported wine 7, and imported wine 12 were 97.16, 96.72 and 94.52%/20 mL wine by DPPH assay and 7.09, 8.07 and 7.28 mg ascorbic acid equivalents per mL wine by ABTS assay, respectively. This study demonstrates potent antioxidant activities of the aroma extracts of commercially available red wines in Korea.

건조 조건이 오미자의 휘발성 terpene류 및 색도에 미치는 영향

오미자의 건조공정에 의한 휘발성 terpene류와 색의 변화를 조사하기 위하여, 건조조건을 <TEX>$50^{\circ}C$</TEX>와 <TEX>$70^{\circ}C$</TEX>의 열풍건조, <TEX>$-70^{\circ}C$</TEX>의 진공동결건조의 3종 건조방법으로 건조한 후 SDE 연속추출장치로 terpene류를 추출하여 GC/MS로 분석하고, 각 건조된 오미자를 마쇄한 분말의 색도를 Hunter colorimeter로 측정하였다. 생오미자의 GC/MS 분석 결과, 15종의 monoterpene류, 28종의 sesquiterpene류 및 7종의 terpene alcohol류가 확인되었으며, 또한 myrcene (56.97 <TEX>${\mu}g/g$</TEX>)과 <TEX>${\gamma}-terpinene$</TEX> (58.49 <TEX>${\mu}g/g$</TEX>)이 monoterpene류, <TEX>${\beta}-elemene$</TEX> (120.16 <TEX>${\mu}g/g$</TEX>), <TEX>${\alpha}$</TEX>-bergamotene (<TEX>$103.45{\mu}g/g$</TEX>), <TEX>${\gamma}$</TEX>-selinene (75.97 <TEX>${\mu}g/g$</TEX>), <TEX>${\beta}$</TEX>-cubebene (66.69 <TEX>${\mu}g/g$</TEX>), aristolene (51.25 <TEX>${\mu}g/g$</TEX>) 및 <TEX>${\alpha}$</TEX>-ylangene (28.06 <TEX>${\mu}g/g$</TEX>) 등이 sesquiterpene류, 그리고 T-muurolol (96.45 <TEX>${\mu}g/g$</TEX>)과 terpinen-4-ol (46.02 <TEX>${\mu}g/g$</TEX>)이 terpene alcohol류의 주성분이었다. 건조과정의 초기에 생오미자 terpene류의 절반 이상이 감소되었으며, 이후 건조기간의 경과에 따른 추가적 감소는 아주 적었다. 또한 총 terpene류의 절반 이상을 차지하는 sesquiterpene류의 함량은 진공동결건조에서는 소량 증가하다 6일 이후 감소하는 패턴을 보였다. 그리고 terpene alcohol류는 진공동결건조한 시료에서 그 함량이 비교적 많이 남았으나, 고온인 <TEX>$70^{\circ}C$</TEX>에서 열풍건조한 시료에서는 가장 적게 남아 있었다. 건조방법에 따른 L값은 동결건조, <TEX>$50^{\circ}C$</TEX> 열풍건조, <TEX>$70^{\circ}C$</TEX> 열풍건조 순서로 높았으며, a값 및 b값도 동결건조에서 가장 높았으며 <TEX>$70^{\circ}C$</TEX> 열풍건조에서 가장 낮게 나타났다. Schizandra fruit (Schizandra chinensis fructus) were dried by three processes, <TEX>$50^{\circ}C$</TEX> (50HAD), <TEX>$70^{\circ}C$</TEX> hot air (70HAD) and freeze drying process (FRD). Terpenoid were collected by SDE(Simultaneous Steam Distillation-Extraction) and followed by GC-MSD analysis. Also colour profile of each dried samples were measured by Hunter colorimeter. From fresh schizandra fruit, were detected 15 kinds of monoterpene, 28 kinds of sesquiterpene and 7 kinds of terpene alcohol. Myrcene(56.97 <TEX>${\mu}g/g$</TEX>) and <TEX>${\gamma}$</TEX>-terpinene(58.49 <TEX>${\mu}g/g$</TEX>) were the major monoterpenes, <TEX>${\beta}$</TEX>-elemene(120.16 <TEX>${\mu}g/g$</TEX>), <TEX>${\alpha}$</TEX>-bergamotene (103.45 <TEX>${\mu}g/g$</TEX>), <TEX>${\gamma}$</TEX>-selinene (75.97 <TEX>${\mu}g/g$</TEX>), <TEX>${\beta}$</TEX>-cubebene(66.69 <TEX>${\mu}g/g$</TEX>), aristolene (51.25 <TEX>${\mu}g/g$</TEX>) and <TEX>${\alpha}$</TEX>-ylangene(28.06 <TEX>${\mu}g/g$</TEX>) were the sesquiterpenes, and T-muurolol (96.45 <TEX>${\mu}g/g$</TEX>) and terpinen-4-ol(46.02 <TEX>${\mu}g/g$</TEX>) were the terpene alcohols. The dried samples lost more than half of terpenoid content of fresh schizandra fruit during early stage of drying process, and then the level of terpenoid content was not significantly changed. The content of sesquiterpenes appeared to increase until 6 day of FRD. The amount of residual terpene alcohols contained in schizandra fruit dried by FRD was more than those remained after drying by other processes, and schizandra fruit dried by 70HAD exhibited the least residual terpene alcohols. Brightness parameter <TEX>$L^{\ast}$</TEX> decreased with the rise in the level of drying temperature, to which redness parameter <TEX>$a^{\ast}$</TEX> and yellowness <TEX>$b^{\ast}$</TEX> appeared to be similar.

Roasted Chicory Aroma Evaluation by Gas Chromatography/Mass Spectrometry/Olfactometry

Volatiles were isolated from roasted chicory by simultaneous steam distillation-solvent extraction (SDE) and dynamic headspace sampling (DHS). Many volatile components were identified in SDE (92) and DHS (64) extracts. Many pyrazines and N-furfurylpyrroles (N-furfurylpyrrole, N-furfuryl-2-formylpyrrole, and N-furfuryl-2-acetylpyrrole) were identified for the first time in roasted chicory. Aroma extract dilution analysis showed that those extracts from SDE and DHS were similar with respect to predominant aroma-active components. 2-Ethyl-3,5-dimethylpyrazine, 2,3-butanedione, 1-octen-3-one, 3-methylbutanal, and one unknown compound with a chicory- and burnt sugar-like note were the most intense aroma-active components found in roasted chicory.

Characterization of Volatile Components in Field Bean (Dolichos lablab) Obtained by Simultaneous Steam Distillation and Solvent Extraction

Volatile components in field bean (Dolichos lablab) were collected by simultaneous steam distillation and solvent extraction and analyzed by gas chromatography-mass spectrometry. One hundred and five components were identified including alcohols (32), ketones (18), aldehydes (9), acid (1), alkanes (5), aromatics compounds (4), esters (2), furans (2), naphthalene (1), pyrazines (4), pyridine (3), sulfur-containing compounds (4) and terpenes (7) and miscellaneous compounds (13). Relatively high concentration of n-hexanal found in the field bean might be undesirable to some consumers.

전자선 조사가 신고배의 향기성분에 미치는 영향

신고배(Pyrus pyrifolia cv. Niitaka)의 휘발성 향기성분에 전자선 조사의 영향과 전자선 조사 후 저장기간에 따른 휘발성 향기성분의 변화를 확인하기 위하여 본 연구를 수행하였다. SDE 추출방법과 GC/MS 분석에 의하여 선량에 따른 신고배의 휘발성 향기성분을 분석하였다. 비조사 신고배와 전자선 0.25, 0.5, 1 그리고 3 kGy로 조사된 신고배에서 각각 46, 45, 44, 48 그리고 51종의 화합물을 동정하였다. 신고배의 주요 휘발성 향기성분으로는 C?화합물인 hexanal, n-hexanol, (E)-2-hexenal이 분리 동정되었다. 4℃에서 30일 저장 후 신고배의 휘발성 향기성분의 조성은 유사하였으며, 저장기간 동안 크게 변화가 없었다. 소비자 수용성에 기여하는 휘발성 향기성분에 대하여 전자선 조사는 휘발성 향기성분의 변화에 크게 영향을 미치지 않는 것으로 판단되었다. 관능평가 실시 결과, 1 kGy 이하의 저선량으로 전자선 조사된 배의 기호도가 대조군보다 오히려 약간 높은 것으로 나타났으며 유의적인 차이는 없었다. 위의 결과를 토대로 신고배의 전자선 조사기술을 적용하기 위해서는 다양한 실험방법을 통한 지속적인 연구가 필요할 것으로 사료된다.

Aroma characterisation of Gouda-type cheeses

The aim of this study was to characterise flavour differences between short-ripened Gouda-type cheeses produced from raw and pasteurised milk and to follow, in the case of pasteurised milk cheeses, flavour evolution during ripening. The volatile composition of the cheeses was studied using a combination of simultaneous steam distillation–extraction and gas chromatography–mass spectrometry. Visualisation of the analytical results was performed by principal component analysis. A clear differentiation between raw milk cheese and pasteurised milk cheese was observed and the evolution of the volatile composition of the pasteurised cheese samples during ripening was clearly demonstrated. Partial least squares regression was used to examine possible relationships between the chemical–analytical and sensory descriptive data.

산지별 마늘의 향기 항산화활성과 열처리 효과

The objectives of this study were to compare the aroma characteristics and antioxidant activity of raw and heated garlic (130℃, 2 hr) from different cultivation areas (Danyang, Seosan, Uiseong Namhae, Namdo, Daeseo and China). The volatile compounds were extracted by simultaneous steam distillation extraction and identified with gas chromatography/mass spectrometer. The major volatile compounds of raw garlic were sulfur compounds such as diallyl disulfide, methyl-2-propenyl trisulfide, di-2-propenyl trisulfide etc. After heating, the major volatile compounds were allyl mercaptan, methyl pyrazine, 2,2-dimethyl-1,3-dithiane, 2-propenyl propyl disulfide, allyl methyl sulfide, allyl alcohol, and allyl sulfide etc. The DPPH radical scavenging activity (EDA, %) of volatile compounds from raw garlic and heated garlic was increased in a dose-dependent manner. The antioxidant activities (EDA, %) of volatile compounds from raw garlic cultivated in Danyang, Namhae and China were 20.07, 34.62, and 9.71% respectively. After heating, these values were increased to 79.90, 93.59, and 77.26% respectively. Results showed that heat treatment significantly enhanced the antioxidant activities (EDA, %) of the garlic.

Effect of Supercritical Carbon Dioxide Decaffeination on Volatile Components of Green Teas

Volatile components in regular and decaffeinated green teas were isolated by simultaneous steam distillation and solvent extraction (SDE), and then analyzed by GC-MS. A total of 41 compounds, including 8 alcohols, 15 terpene-type compounds, 10 carbonyls, 4 N-containing compounds, and 4 miscellaneous compounds, were found in regular and decaffeinated green teas. Among them, linalool and phenylacetaldehyde were quantitatively dominant in both regular and decaffeinated green teas. By a decaffeination process using supercritical carbon dioxide, most volatile components decreased. The more caffeine was removed, the more volatile components were reduced in green teas. In particular, relatively nonpolar components such as terpene-type compounds gradually decreased according to the decaffeination process. Aroma-active compounds in regular and decaffeinated green teas were also determined and compared by aroma extract dilution analysis (AEDA). Most greenish and floral flavor compounds such as hexanal, (E)-2-hexenal, and some unknown compounds disappeared or decreased after the decaffeination process.

Effects of gamma irradiation on the yields of volatile extracts of Angelica gigas Nakai

The study was carried out to determine the effects of gamma irradiation on the volatile flavor components including essential oils, of Angelica gigas Nakai. The volatile organic compounds from non- and irradiated A. gigas Nakai at doses of 1, 3, 5, 10 and 20 kGy were extracted by a simultaneous steam distillation and extraction (SDE) method and identified by GC/MS analysis. A total of 116 compounds were identified and quantified from non- and irradiated A. gigas Nakai. The major volatile compounds were identified 2,4,6-trimethyl heptane, α-pinene, camphene, α-limonene, β-eudesmol, α-murrolene and sphatulenol. Among these compounds, the amount of essential oils in non-irradiated sample were 77.13%, and the irradiated samples at doses of 1, 3, 5, 10 and 20 kGy were 84.98%, 83.70%, 83.94%, 82.84% and 82.58%, respectively. Oxygenated terpenes such as β-eudesmol, α-eudesmol, and verbenone were increased after irradiation but did not correlate with the irradiation dose. The yields of active substances such as essential oil were increased after irradiation; however, the yields of essential oils and the irradiation dose were not correlated. Thus, the profile of composition volatiles of A. gigas Nakai did not change with irradiation.

Volatile organic compounds of Angelica gigas Nakai, Korean medicinal herb

The study was performed to find out the profile of volatile flavor components from the aromatic medicinal plant, Angelica gigas Nakai. The volatile organic compounds of A. gigas Nakai were extracted by simultaneous steam distillation and extraction (SDE) method, and identified by gas chromatograph/mass spectrometric (GC/MS) analysis. A total of 116 compounds, including 40 hydrocarbons, 37 alcohols, 15 esters, 12 aldehydes, 7 ketones, and 5 miscellaneous were identified and quantified. Among them, 75 volatile organic compounds were detected which make up 90.52% of total volatile content. α-Pinene was detected as the prime volatile component which accounted for 30.89% of total volatile content and 2,4,6-trimethyl heptane, camphene, α-limonene, β-eudesmol, vervenol, α-murrolene, and sphatulenol were detected as the major components of A. gigas Nakai.

V-SDE와 SPME법에 의한 꽃게(Portunus trituberculatus)육의 휘발성 향기성분 비교

Volatile flavor compounds in meat of the blue crab Portunus trituberculatus were compared using vacuum simultaneous steam distillation-solvent extraction (V-SDE) and solid phase microextraction (SPME)/ gas chromatography (GC)/ mass selective detection (MSD) methods. A total of 100 volatile flavor compounds were identified by both methods: 77 by V-SDE and 59 by SPME. These compounds were composed of 17 aldehydes, 12 ketones, 19 alcohols, 5 esters, 4 sulfur-containing compounds, 6 nitrogen-containing compounds, 23 aromatic compounds, 6 hydrocarbons, 2 terpenes, and 6 miscellaneous compounds. Although more compounds were detected using V-SDE than using SPME, the levels of all groups detected, except esters, were higher using SPME than using V-SDE. In addition to trimethylamine, aldehydes, and aromatic compounds, the S- and N-containing compounds with low thresholds are thought to have positive roles for flavors in the meat of the blue crab.

Comparison of Headspace Solid-Phase Microextraction with Simultaneous Steam Distillation Extraction for the Analysis of the Volatile Constituents in Chinese Apricot

Volatile constituents in fully mature fruits of apricot ( Prunus armeniaca L.) cultivar Xinshiji were extracted using headspace solid-phase microextraction (HS-SPME) and simultaneous steam distillation extraction (SSDE) and then analyzed using capillary gas chromatography and gas chromatography-mass spectrometry. A total of 70 components were identified by HS-SPME, including 20 esters, 19 hydrocarbons, 5 alcohols, 5 ketones, 4 acids, 4 lactones, 3 aldehydes, and 10 miscellaneous components, with the esters being the dominant constituent. On the basis of the odor unit values, it is believed that the following compounds probably contributed to the fresh apricot odor: hexyl acetate, β-ionone, butyl acetate, (E)-2-hexcnal, linalool, limonene, γ-decalactone, and hexanal. A total of 49 components were also detected by SSDE, including 13 hydrocarbons, 9 alcohols, 7 aldehydes, 9 esters, 4 ketones, 4 lactones, 2 acids, and 1 miscellaneous component, of which the monoterpene alcohols were the dominant constituents. It could be judged from the odor unit values that the following compounds were the major contributors to boiled apricot aroma: β-ionone, linalool, hexyl acetate, γ-dodecalactone, γ-decalactone, (E)-2-hexenal, hexanal, γ-octalactone, phenylacetaldehyde, butyl acetate, limonene, α-terpineol, and δ-decalactone. The results show that HS-SPME is a simple, rapid, and solvent-free method, which is an alternative to the classical SSDE.

Activity of gaseous phase steam distilled propolis extracts on peroxidation and hydrolysis of rice lipids

The effects of simultaneous steam distilled extracts of Brazilian propolis in the static gas phase on curbing peroxidation and hydrolysis in rice lipids were examined. Gas chromatograph–mass spectrometry analysis and subsequent fragment pattern identification revealed the presence of over 30 compounds. Propene, acetophenone and beta-linalool were some of the dominant fractions. The peroxide value (POV) of extracted rice bran lipids was lower in samples treated with propolis extract than in rosemary oil-soluble (RM21Bbase) and water-soluble (RM21Abase) extracts that were used as positive controls. Except for rosemary oil-soluble extract (RM21Bbase), the rest of the treatments (propolis and rosemary water-soluble (RM21Abase) extracts) suppressed the accumulation of α-linolenic and linoleic acids. Assessment of the lipolytic associated freshness indices: plate count agar for total aerobic bacterial count, potato dextrose agar for total yeast, and mold counts as well as carbon dioxide evolution of the stored brown rice revealed a strong antimicrobial activity associated with the depression of carbon dioxide evolution after treatment with propolis extracts. This is the first report on Brazilian propolis extract in the static gas phase displaying an antilipolytic efficacy on rice lipids.

건생강에 함유된 키랄성 향기성분의 이성질체 조성 분석

The volatile compounds of Zingiber officinale Roscoe were extracted by simultaneous steam distillation and extraction (SDE) method and identified with gas chromatography/mass spectrometer (GC/MS) analysis. Enantiomeric compositions of chiral compounds were determined by multidimensional gas chromatography/ mass spectrometer (MDGC/MS). A total of 57 compounds were identified and quantified, including zingiberene, β-sesquiphellandrene, β-bisabolene, (E,E)-α-farnesene and α-curcumene. Among them, zingiberene (38.41%) was found as the predominantly abundant component. α-Pinene and nerolidol in dried ginger were detected by high enantiomeric purity (＞96%) for (S)-form, and β-pinene was detected only (R)-form. The enantiomeric composition of α-terpineol revealed 72.0% for (R)-form, and linalool and 4-terpineol showed mixtures of both enantiomers. (S)-Enantiomer was the major enantiomer of limonene having enatiomeric excess of 17.2%. Hence the enantiomeric composition of these compounds can be used as parameter for authenticity control of Zingiber officinale.

Volatile constituents of cooked bullfrog ( Rana catesbeiana) legs

Volatile extracts obtained from pressure-cooked bullfrog legs by simultaneous steam distillation and solvent extraction were analyzed by gas chromatography–mass spectrometry. Although the raw bullfrog legs used in this study contained 0.6% fat only, the extracts were dominated (qualitatively and quantitatively) by lipid oxidation volatiles such as alkanals, alkenals, alkadienals, alkanols and alkenols. Few Maillard volatiles were found, amongst them 2-acetylthiazole, the only sulfur-containing compound found in the extract. This profile of volatiles may be explained by the high proportion of phospholipids and low concentration of sulfur amino acid cystine in raw bullfrog meat, as previously reported by other researchers. Odour activity values (OAV) of volatiles were also estimated and major OAV compounds were: ( E, E)-2,4-decadienal, ( E, Z)-2,4-decadienal, ( E, Z)-2,6-nonadienal, 1-octanol, and ( E)-2-nonenal. Some of these potent unsaturated aliphatic aldehydes have also been associated with chicken flavour. This may contribute to flavour resemblances between bullfrog and chicken meat.

부재료 첨가에 따른 별미장의 향기특성

Aroma compounds in four different Byeolmijang made from optional ingredient addition were extracted by SDE (simultaneous steam distillation extraction) and analyzed with GC (gas chromatography) and GC/MS (mass-spectrometry). The major aroma compounds in the four different Byeolmijang during aging were 1-octene-3-ol, hexanal, benzeneacetaldehyde, benzaldehyde, fufural, pyrazine, furan and phenol type compounds. Generally, benzeneacetaldehyde, benzaldehyde, fufural and phenol type compounds were increased during aging. On the other hand, 1-octen-3-ol, hexanal and furan were decreased during aging. Furfural, 2-furanmathanol and benzeneacetaldehyde in Sanghwangjang, 3-methyl-1-butanol, phenol and 1H-indole in Mujang, hexanal, 1-octen-3-ol and 2,4-decadienal in Bizijang and hexanal, tetramethylpyrazine and 2-methoxy-4-vinylphenol in Jigeumjang were identified as major aroma compounds, respectively. Generally, the major aroma compound in four different Byeolmijang with optional ingredient was similar with control and pyrazine, furan and phenol type compounds were decreased to addition with optional ingredient. The major aroma compound in Sanghwangjang with optional ingredient (onion) were 1-hexanol and 2,5-dimethylthiophene and the major aroma compounds were 1,2,4-trithiolane and 2-buthyl-2-octenal in Mujang with optional ingredient (Letinus edodes). Furfural, benzaldehyde, benzeneacetaldehyde, 1,2,4-trithiolane and lenthionine were detected in Bizijang due to the addition of powdered Letinus edodes. Linaool and were detected in Jigeumjang due to the addition of powdered red pepper.

Partial oxidation of methane to syngas with or without simultaneous steam or CO 2 reforming over a high-temperature stable-NiCoMgCeO x supported on zirconia–hafnia catalyst

A NiCoMgCeO x (Ni/Co/Mg/Ce:1:0.2:1.2:1.2)/zirconia–hafnia catalyst with unusually high thermal stability has been investigated for syngas generation via a process that includes the catalytic partial oxidation of methane (CPOM), the oxidative steam reforming of methane (OSRM) and the oxidative CO 2 reforming of methane (OCRM). The catalyst calcined at 1400 °C (for 4 h) showed excellent activity/selectivity for the CPOM, OSRM and the OCRM reactions; furthermore no catalyst deactivation was observed for a period of 20 h. For the CPOM process, the selectivity for H 2 was >95% at reaction temperatures ≥650 °C; however temperatures above 800 °C were required to achieve >95% CO selectivity. While the reaction temperature had a considerable influence on the CPOM product H 2/CO ratio, the space velocity (at 850 °C) did not affect it to any significant extent. For the OSRM process, the H 2O/CH 4 ratio and the reaction temperature had a strong effect on the product H 2/CO ratio and the heat of the reaction; depending on the H 2O/CH 4 ratio and reaction temperature, the OSRM process could be operated in a mildly exothermic, thermoneutral or mildly endothermic mode. The CO 2 conversion was very strongly affected by the reaction temperature in the OCRM process; reasonably high CO 2 conversion (>40%) could only be obtained at high OCRM reaction temperatures (>850 °C). The exothermicity of the OCRM reaction was found to decrease with increasing reaction temperature.

Comparison of Odor-Active Volatile Compounds of Fresh and Smoked Salmon

The odorant volatile compounds of raw salmon and smoked salmon have been investigated by two gas chromatography-olfactometry methods (frequency detection and odorant intensity) and gas chromatography-mass spectrometry. After simultaneous steam distillation-solvent extraction with diethyl ether and the recovery of the aromatic extract in ethanol, qualitative olfactometric characterization and identification followed by a quantitative assessment of the odorant volatile compounds were carried out. The origin of many odorant compounds of smoked salmon can be attributed to wood smoke. Another part of smoked salmon aroma is due either to the odorant compounds of the raw fish flesh or to an evolution of fish flesh aroma thanks to the smoking process conditions. Forty-nine odorant compounds have been identified in fresh salmon and 74 in smoked salmon. Carbonyl compounds, such as heptanal or (E,Z)-2,6-nonadienal, show a high detection frequency and odorant intensity in unsmoked fish, giving the flesh its typical fishy odor. For smoked salmon, phenolic compounds, such as cresol or guaiacol, and furanic compounds seem to be responsible for the smoked odor.