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Volatile Compounds (volatile + compound)
Kinds of Volatile Compounds Selected AbstractsCOMPARISON OF VOLATILE COMPOUNDS AND CHEMICAL AND PHYSICAL PROPERTIES IN ORANGE JUICE FROM DIFFERENT PARTS OF JINCHEN FRUITJOURNAL OF FOOD QUALITY, Issue 2 2010YU QIAO ABSTRACT Jinchen is a native sweet cultivar of Citrus sinensis and one of the most important varieties used in orange juice processing in China. The study of flavor components of Jinchen orange juice has not been carried out before. In this paper, the color characteristics, pH value, total soluble solids, total acids, as well as organic acids and sugars were determined in Jinchen orange juice from different parts of fruit (peeled juice, pulp juice, whole fruit juice). The color characteristics were significantly different among three types of Jinchen orange juice. The level of vitamin C and total soluble solids/total acids ratio (TSS/TA) is higher in whole fruit juice. The organic acids and sugars also changed. Pulp juice is rich in the highest amounts of organic acids and sugars. Volatiles from three juices were studied using the solid phase microextraction (SPME) combined with gas chromatography/mass spectrometry. The whole fruit juice has the highest amount of volatile compounds (53.07 mg/L) followed by peeled juice (51.044 mg/L) and pulp juice (27.107 mg/L). Some differences in the constituents of the volatile compounds of three type juices were observed. These results indicated that volatile compounds and quality properties differed in Jinchen orange juice from different parts of fruit. PRACTICAL APPLICATIONS The peeled orange fruits are usually used for juice processing. Great amounts of aroma components with intensive odor are located in the peel of orange. The aroma of pulp possessing weak fresh citrus odor is different from peel. The different parts of the orange utilized in processing have direct impact on juice quality. It is very essential to obtain the data of chemical and physical properties in juice from different parts of orange fruit. The quality information could be used to modify the orange aroma. [source] COMPARISON OF HEADSPACE SOLID PHASE MICROEXTRACTION AND XAD-2 METHODS TO EXTRACT VOLATILE COMPOUNDS PRODUCED BY SACCHAROMYCES DURING WINE FERMENTATIONSJOURNAL OF FOOD QUALITY, Issue 1 2006JEFFRI C. BOHLSCHEID ABSTRACT A modified headspace solid phase microextraction (HS-SPME) method was compared with Amberlite® XAD-2 resin for the extraction of volatile compounds. In the HS-SPME method, volatiles were extracted using an 85 ,m polyacrylate fiber from wines that contained a standardized amount of ethanol (10% v/v), NaCl (0.325 g/mL) and internal standards (dodecanol and nonanoic acid). Both extraction procedures yielded high relative recoveries (>92%) and reproducibilities (coefficient of variations , 11%) for the different higher alcohols, esters and medium-chain fatty acids. Overall, limits of detection for the HS-SPME and XAD-2 methods were below sensory threshold concentrations. HS-SPME and XAD-2 performed similarly in the analysis of a Riesling wine; however, the HS-SPME method did not require organic solvents and was generally quicker to perform. In applying the HS-SPME method, differences in concentrations of volatile compounds produced in Riesling and Chenin blanc wines by 11 different yeast strains were noted. [source] Analysis of Volatile Compounds Emitted by the Helicobacter pylori Reference Strain NCTC 11637 In VitroHELICOBACTER, Issue 1 2006Matthias Lechner No abstract is available for this article. [source] Characterization by Volatile Compounds of Microbial Deep Spoilage in Iberian Dry-Cured HamJOURNAL OF FOOD SCIENCE, Issue 6 2010Alberto Martín Abstract:, In the present study, volatile compounds of spoiled dry-cured Iberian ham with deep spoilage or "bone taint" were analyzed and correlated with level of spoilage and the microorganisms detected. Volatile compounds extracted by a solid phase micro-extraction technique were assayed by gas chromatography/mass spectrometry. The spoiled hams were evaluated sensorially, and the correlations among volatile compounds, spoilage level, and microbial counts were studied. The spoiled hams had higher concentrations of hydrocarbons, alcohols, acids, esters, pyrazines, sulfur compounds, and other minor volatile compounds than unspoiled hams. The sensorial analysis showed that the spoilage level of hams correlated with several volatile compounds, most of them associated with Gram-positive catalase positive cocci and,Enterobacteriaceae,counts. Cyclic compounds such as cyclohexanone, some ethers, and pyrazines should be considered as indicators to monitor incipient microbial deep spoilage in the elaboration of this meat product. [source] Analysis of Volatile Compounds in Beef Fat by Dynamic-Headspace Solid-Phase Microextraction Combined with Gas Chromatography,Mass SpectrometryJOURNAL OF FOOD SCIENCE, Issue 5 2008A. Watanabe ABSTRACT:, A solid-phase microextraction (SPME) technique has been applied to the determination of the volatile compounds, including diterpenoids and lactones, in cooked beef fat. The ability of static-headspace SPME to extract lactones was disappointing, regardless of the type of SPME fiber or the temperature used. Dynamic-headspace SPME extraction with 50-/30-,m divinylbenzene-Carboxen on a polydimethylsiloxane fiber at 100 °C, by contrast, enabled the analysis of volatiles, including delta-lactones, gamma-lactones, and diterpenoids, with 50-/30-,m divinylbenzene-Carboxen on a polydimethylsiloxane fiber at 100 °C. Fifty-three compounds were identified from only 0.20 g of rendered beef fat, and 76% of these showed reliable peak size repeatability: the coefficient of variation was less than 10% on the total ion chromatograms obtained from gas chromatography,mass spectrometry (GC,MS) analysis. Some lactones showed higher CV values (>10%), but single-ion mode GC,MS analysis reduced them to 10% or less. In a study of beef samples available to the Japanese market, our analytical procedure revealed significantly higher levels of 1-hexanol, octadecane, ethyl tetradecanoate, gamma-nonalactone, but lower levels of delta-decalactone, delta-dodecalactone, and neophytadiene, in Japanese Black cattle than in beef imported from Australia. [source] Analysis of Headspace Volatile and Oxidized Volatile Compounds in DHA-enriched Fish Oil on Accelerated Oxidative StorageJOURNAL OF FOOD SCIENCE, Issue 7 2003H. Lee ABSTRACT: Oxidative stability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and volatile and oxidized volatile compounds in 2 types of DHA-enriched fish oil, triacylglycerol (TG) and ethyl ester (EE), were studied during storage at 80 °C with aeration. The rate of DHA autoxidation was higher than that of EPA. DHA in EE form was more susceptible to autoxidation than in TG form. Thirty-one volatile compounds were identified in EE and 23 volatile compounds in TG. (E)-2-pentenal, 2-(1-pentenyl) furan, and (E,E)-2,4-heptadienal were commonly detected as oxidized volatile compounds from TG and EE fish oil. These volatile oxidized compounds might be formed mainly from the oxidation of DHA and EPA, the main fatty acids of the oil. [source] Changes of Volatile Compounds, Lactic Acid Bacteria, pH, and Headspace Gases in Kimchi, a Traditional Korean Fermented Vegetable ProductJOURNAL OF FOOD SCIENCE, Issue 3 2003J.H. Kang ABSTRACT Headspace volatiles of Kimchi stored at 5 °C increased over a 7 d period by 20.0% and then decreased from 7 to 27 d by 8.3%. Forty volatile compounds including 18 sulfur compounds were identified in Kimchi. Lactic acid bacteria in Kimchi increased from 3.1 to 4.5 (1 × 108cfu/mL) over a 17-d period and decreased by 40% from 17 to 27 d. As the storage time increased from 2 to 27 d, pH decreased from 4.3 to 3.8, headspace oxygen decreased from 14.3 to 1.3%, and headspace carbon dioxide increased from 27.7 to 45.3%. Enzymatic reactions and chemical oxidations in Kimchi explained the changes of volatile compounds, lactic acid bacteria, pH, headspace oxygen and carbon dioxide. [source] Volatile Compounds of Raw Beef from 5 Local Spanish Cattle Breeds Stored Under Modified AtmosphereJOURNAL OF FOOD SCIENCE, Issue 4 2002K. Insausti ABSTRACT Volatile compounds of raw beef from Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta cattle breeds were studied. Steaks were packaged under 60% O2, 30% CO2, and 10% N2, and 53 volatile compounds were tentatively identified by purge-and-trap extraction and gas chromatography with mass spectrometry after 0, 5, 10, and 15 d of chill storage. The degradation of beef quality with increasing storage time was evidenced by the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-octene, 3-methyl-2-heptene, 2-octene, and 2-propanone and by the decrease in dimethyl sulfide. Consequently, some of the volatile compounds, which are believed to be formed by thermal degradation of meat, might be formed during chill storage, and the rate of formation of some was dependent on the specific compound. [source] Effect of Aging Time on Volatile Compounds, Odor, and Flavor of Cooked Beef from Pirenaica and Friesian Bulls and HeifersJOURNAL OF FOOD SCIENCE, Issue 3 2002C. Gorraiz ABSTRACT: Volatile compounds, odor, and flavor produced by beef from bulls and heifers of the Pirenaica and Friesian breeds were studied during 7 d of aging. The Friesian breed beef had stronger fatty flavor and aftertaste than the Pirenaica, as well as differences in the content of several volatile compounds. Bull beef had stronger liver-like odor and flavor, and bloody flavor that were related to a higher 2-propanone content, while beef from heifers had stronger characteristic flavor. Aging of meat increased characteristic flavor and aftertaste. Ethanal showed a positive correlation with livery flavor and a negative correlation with the characteristic odor. The hexane seems to contribute to fatty flavor, 2-propanone was related to livery and bloody notes, and 2,2,4,6,6-pentamethylheptane to characteristic flavor. [source] Production of Volatile Compounds from Irradiated Oil Emulsion Containing Amino Acids or ProteinsJOURNAL OF FOOD SCIENCE, Issue 4 2000C. Jo ABSTRACT Oil emulsions containing amino acids, glutathione, bovine serum albumin, gelatin, or myofibrillar proteins were prepared. The emulsions were irradiated at 0, 2.5, 5.0, or 10.0 kGy absorbed doses and analyzed for volatile compounds. Irradiation increased the production of aldehydes (for example, hexanal, heptanal, octanal, and nonanal) indicating that lipid oxidation of oil emulsion was accelerated by irradiation. Irradiation produced, by radiolytic degradations, new volatile compounds from oil emulsions containing leucine, valine, isoleucine, phenylalanine, methionine, or cysteine. This indicated that radiolysis of protein may play an important role in off-odor generation of irradiated meat. [source] Fragrant Volatile Compounds in the Liverwort Drepanolejeunea madagascariensis (Steph.) Grolle: Approach by the HS-SPME TechniqueCHEMISTRY & BIODIVERSITY, Issue 3 2010Anne Gauvin-Bialecki Abstract Three populations of the epiphyllous liverwort Drepanolejeunea madagascariensis collected in the cloud forests of Reunion Island (Mascarene Archipelago) were investigated for their volatile compounds, because of the pleasant, sweet, warm, woody-spicy, and herbaceous fragrance, slightly reminiscent of dill, of this species. By applying the headspace solid-phase microextraction (HS-SPME) technique coupled to GC/MS analysis, 34 compounds were detected in total, with p -menth-1-en-9-ol (28.8,43.5%), limonene (10.5,14.7%), , -phellandrene (8.8,11.6%), and the so-called dill ether (8.5,16.6%) as the main components. The presence of 1-epi- , -pinguisene confirms the possible use of pinguisane-type sesquiterpenoids as a characteristic chemical marker for the order Jungermanniales. [source] Volatile Compounds from Melicope obscuraCHEMISTRY & BIODIVERSITY, Issue 2 2010Jacqueline Smadja Abstract To evaluate the interpopulation variability of volatile compounds in Melicope obscura, four samples representing four populations were collected all over the distribution area of the species in Reunion Island (Indian Ocean). The samples were extracted by hydrodistillation, and analyzed using GC/FID and GC/MS techniques. The study revealed that, in the four essential oils obtained, oxygenated sesquiterpenes were one of the major chemical classes (9.2,35.2%), mainly consisting of a new compound, (+)-6-ethenyl-2-hydroxy-6,10-dimethylundeca-2,9-dien-4-one (1), called melicopenol (8.6,30.1%). The compound was isolated by column chromatography and identified by spectral analyses including 1D- and 2D-NMR. [source] Studies on the Volatile Compounds of Roasted Spotted ShrimpCHEMISTRY & BIODIVERSITY, Issue 12 2004Toru Tachihara The aroma of spotted shrimp (Sergia lucence Hansen) was analyzed upon roasting to determine the components that constitute the characteristic roasted shrimp flavor. Our analyses resulted in the identification of ca.,200 volatiles, including high-impact sulfur and nitrogen compounds. In addition, we synthesized all possible stereoisomers of the pyrrolidine derivatives 1 and 4, and of the imine derivatives 16 and 18,20, which are very characteristic for the aroma. The odor evaluation of these chemicals revealed distinct differences, each possessing different aroma characteristics. [source] Influence of extraction temperature on the final quality of espresso coffee,JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2003Susana Andueza Abstract The final quality of espresso coffee (EC) depends upon certain technical conditions, such as the extraction temperature used in preparing it. The aim of this work was to investigate the effects of water temperature (88, 92, 96 and 98,°C) on the final quality of three types of EC (Arabica, Robusta Natural blend and Robusta Torrefacto blend) in order to select the optimal temperature. Volatile compound (analysed by Static headspace gas chromatography/mass spectrometry) and sensory flavour profiles were the most relevant parameters, whereas physicochemical, taste and mouthfeel parameters were not very useful for selecting the water temperature. For Arabica and Robusta Natural blend ECs, 92,°C was the optimal water temperature. For Robusta Torrefacto blend EC the overall acceptability might lead to the selection of 88,°C as the ideal water temperature, but the high percentages of key odorants related to roasty and earthy/musty flavours and the ,not hot enough' perception dictated the selection of 92,°C in this case as well. © 2003 Society of Chemical Industry [source] Volatile compounds of original African black and white shea butter from Tchad and CameroonEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 7 2006Sabine Krist Abstract Shea butter is used as an edible vegetable fat in many African countries. It can be utilized as a substitute or complete replacement for cocoa butter in various applications and plays an important role in traditional African medicinal practice. Although detection of volatile compounds by solid-phase micro-extraction gas-chromatography mass-spectroscopy (SPME-GC-MS) is a very reliable and reproducible technique, which can be used as an important part of authenticity checking, production monitoring and contamination detection, no published data about volatile compounds of shea butter are available so far. In this investigation, the characteristic volatiles in the headspace of original African shea butter samples were identified by using SPME-capillary-GC coupled to a mass selective detector. Almost 100,different volatile components were identified, e.g. fatty acids, saturated and unsaturated aldehydes and ketones, terpenes, and typical Maillard reaction products such as methylfuranes and pyrazines. Furthermore, the samples have been olfactorily evaluated by a panel of professional flavorists and trained analytical chemists. It can be stated that variations in processing conditions of shea butter result in considerable differences in the composition of headspace volatiles, detected by SPME-GC-MS and human olfaction. [source] Volatile compounds after spontaneous fermentation of musts from Vitis vinifera cv. Albariño grapes cultivated in different origins from Rías Baixas AOC, SpainFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2006S. Zamúz Abstract White wines experimentally produced from the white grape variety Albariño from three different areas from Rias Baixas AOC, north-western Spain, have been analysed in this study. The contents of terpenes, C13 -norisoprenoids, alcohols, acetates and ethyl esters were determined by GC,MS. The Albariño wines from O Rosal are characterized by a high content of higher alcohols, while wines from Val do Salnés show the highest concentrations of free terpenes, acetates and ethyl esters; and wines of Condado do Tea show the highest concentrations of C13 -norisoprenids, principally due to the ,-ionone. Two principal components accounting for 90.7% of the total variance were calculated by means of a principal components analysis (PCA), and the graphical representation of these two components allows grouping the wines according their respective origins. Volatile compounds with fruity and floral odours showed the highest odour activity values, contributing in a great measure to the aroma of Albariño wines. Copyright © 2006 John Wiley & Sons, Ltd. [source] Volatile composition of the laksa plant (Polygonum hydropiper L.), a potential source of green note aroma compoundsFLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2005J. Jiang Abstract Volatile compounds were extracted from laksa plant (Polygonum hydropiper L.) by three isolation techniques,dynamic headspace sampling, simultaneous distillation and extraction (SDE) and liquid,liquid extraction with dichloromethane (DCM). In the GC,MS analysis of the volatile extracts, a total of 46 compounds were identi,ed, including 14 carbonyls, 14 alcohols, 10 hydrocarbons, four esters, two furans, one acid and one base. Carbonyls (aldehydes/ketones) and alcohols are the predominant classes of volatile compounds, accounting for almost 90% (or above) of the total volatiles extracted from the plant. The major compounds include dodecanal (3,40%), (E)-2-hexenal (20,35%), decanal (4,22%), (Z)-3-hexen-1-ol (4,31%), hexanal (1.7,5.1%) and , -caryophyllene (1.7,2.3%). Signi,cantly high levels of both (E)-2-hexenal (leaf aldehyde) and (Z)-3-hexen-1-ol (leaf alcohol) may make the weed plant become a potential source of green note aroma componds. More (Z)-3-hexen-1-ol was found in the stem while more (E)-2-hexenal was detected in the leaf. The laksa stem appeared to contain more decanal and dodecanal but less esters than the leaf. Different isolation techniques produced volatile extracts with different proportions of the major volatile components. Copyright © 2005 John Wiley & Sons, Ltd. [source] Volatile constituents of benzoin gums: Siam and Sumatra.FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2003Part Abstract The volatile extract composition of two different benzoin gums, Siam and Sumatra, were analysed by GC,MS. Twenty components representing more than 99.1% of the oil from Siam and 29 components representing more than 97.4% of the oil from Sumatra were analysed. The major components were benzyl benzoate (76.1,80.1%) for the two oils and benzoic acid (12.5%), methyl benzoate (1.5%) and allyl benzoate (1.5%) for Siam, and styrene (2.3%), cinnamic acid (3.5%) and benzyl cinnamate (3.3%) for Sumatra. Volatile compounds of oils and crushed benzoins were also studied using solid-phase microextraction (SPME) employing carboxen/polydimethylsiloxane and carbowax/divinylbenzene ,bres. Copyright © 2003 John Wiley & Sons, Ltd. [source] Volatile compounds characterising Tunisian virgin olive oils: the influence of cultivarINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2010Dhouha Krichene Summary In this work, the volatile profiles of four Tunisian virgin olive oils were established by headspace-solid phase microextraction and gas chromatography, using flame ionisation and mass spectrometer detectors. More than eighty compounds were isolated and characterised, representing 97,99% of the total GC area. The main volatile compounds present in the oil samples were determined quantitatively, the major constituents were often aldehydes, particularly (E)-2-hexenal (48,90%). Significant differences in the content of volatile constituents were observed. These quantitative differences were used to distinguish between virgin olive oils from different varieties. [source] DETECTION OF OLIVE OIL ADULTERATION WITH RAPESEED AND SUNFLOWER OILS USING MOS ELECTRONIC NOSE AND SMPE-MSJOURNAL OF FOOD QUALITY, Issue 1 2010SYLWIA MILDNER-SZKUDLARZ ABSTRACT The study analyzed the effectiveness of two types of electronic nose systems to detect adulteration of extra virgin olive oil (EVOO) with rapeseed and sunflower oils. Tested methods included volatile analysis with the electronic nose based on MOS sensors (HS-E nose) and by direct coupling of SPME to MS (SPME-MS). Volatile compounds were analyzed also by SPME-GC/MS. Samples of EVOO were mixed with different proportions, ranging from 5 to 50% (v/v), of seed oils and fingerprints of volatile profiles of all samples were generated. In order to obtain as much chemical information as possible and to find a volatile marker to detect adulterations of EVOO with seed oils, principal component analysis (PCA) and partial least squares (PLS) analyses were applied to the data. The application of PCA and PLS analyses to the data from two electronic noses and SMPE-GC/MS were sufficient to differentiate the adulterated samples from pure EVOO. Excellent results were obtained in the prediction of the percentage of adulteration by PLS analysis. SPME-GC-MS analysis with subsequent PCA yielded good results; however, it was time-consuming. The two electronic noses, with subsequent PCA treatment of data, offering the advantages of rapidity and reliability, enabled detection of olive oil adulteration with different contents of seed oils. PRACTICAL APPLICATIONS Virgin olive oil is highly appreciated by consumers due to its nutritional benefits. Thus, its adulteration with low-grade olive oils or cheaper vegetable oils could potentially be very profitable for sellers or raw material suppliers and may yield large economic profits. In this way, authentication of virgin olive oils has become an interesting subject from both commercial and health perspectives. It has been proved that the two proposed types of electronic nose systems facilitate reliable detection of rapeseed and sunflower oils in extra virgin olive oil. Both MOS and MS electronic noses are faster than the conventional SMPE-GC/MS analysis. These well-correlated methodologies, offering the advantages of rapidity and reliability, opened up a new way of detecting adulteration of virgin olive oils. [source] Characterization by Volatile Compounds of Microbial Deep Spoilage in Iberian Dry-Cured HamJOURNAL OF FOOD SCIENCE, Issue 6 2010Alberto Martín Abstract:, In the present study, volatile compounds of spoiled dry-cured Iberian ham with deep spoilage or "bone taint" were analyzed and correlated with level of spoilage and the microorganisms detected. Volatile compounds extracted by a solid phase micro-extraction technique were assayed by gas chromatography/mass spectrometry. The spoiled hams were evaluated sensorially, and the correlations among volatile compounds, spoilage level, and microbial counts were studied. The spoiled hams had higher concentrations of hydrocarbons, alcohols, acids, esters, pyrazines, sulfur compounds, and other minor volatile compounds than unspoiled hams. The sensorial analysis showed that the spoilage level of hams correlated with several volatile compounds, most of them associated with Gram-positive catalase positive cocci and,Enterobacteriaceae,counts. Cyclic compounds such as cyclohexanone, some ethers, and pyrazines should be considered as indicators to monitor incipient microbial deep spoilage in the elaboration of this meat product. [source] Characterization of a Cabbage Off-flavor in Whey Protein IsolateJOURNAL OF FOOD SCIENCE, Issue 2 2006Joy M. Wright ABSTRACT Whey protein isolate (WPI) is a value-added protein with multiple ingredient applications. A bland flavor is expected in WPI, and off-flavors can limit its use in foods. Recently, a cabbage off-flavor was noted in some WPI. The objective of this study was to characterize the source of cabbage flavor in WPI. WPI with and without cabbage flavor were collected, and descriptive sensory analysis was conducted on the rehydrated WPI using a trained panel and a previously identified sensory language. Volatile compounds were extracted by solvent extraction followed by solvent-assisted flavor evaporation (SAFE), followed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GCO), to identify and characterize aroma-active compounds. Dimethyl trisulfide (DMTS) (cabbage aroma) was identified by GCO and GC-MS in WPI with the cabbage flavor. DMTS was quantified by solid-phase microextraction (SPME) with GC-MS. Orthonasal thresholds of DMTS in deodorized water and WPI were determined by ascending forced choice analysis, and descriptive analysis of model systems was used to confirm instrumental results. DMTS levels were 1.94 ± 0.26 and 3.25 ± 0.61 parts per billion (ppb) in WPI with cabbage flavor, and 0.44 ± 0.25 and 0.43 ± 0.18 ppb in those without cabbage flavor. The orthonasal thresholds for DMTS in water and WPI were 0.07 ± 1.28 parts per trillion (ppt) and 0.80 ± 0.45 ppb, respectively. Descriptive analysis of model systems confirmed the role of DMTS in the cabbage off-flavor. Knowledge of the source of this flavor will aid in identification of ways to minimize or prevent DMTS formation in WPI. [source] Volatile Compounds of Raw Beef from 5 Local Spanish Cattle Breeds Stored Under Modified AtmosphereJOURNAL OF FOOD SCIENCE, Issue 4 2002K. Insausti ABSTRACT Volatile compounds of raw beef from Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta cattle breeds were studied. Steaks were packaged under 60% O2, 30% CO2, and 10% N2, and 53 volatile compounds were tentatively identified by purge-and-trap extraction and gas chromatography with mass spectrometry after 0, 5, 10, and 15 d of chill storage. The degradation of beef quality with increasing storage time was evidenced by the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-octene, 3-methyl-2-heptene, 2-octene, and 2-propanone and by the decrease in dimethyl sulfide. Consequently, some of the volatile compounds, which are believed to be formed by thermal degradation of meat, might be formed during chill storage, and the rate of formation of some was dependent on the specific compound. [source] Effect of Aging Time on Volatile Compounds, Odor, and Flavor of Cooked Beef from Pirenaica and Friesian Bulls and HeifersJOURNAL OF FOOD SCIENCE, Issue 3 2002C. Gorraiz ABSTRACT: Volatile compounds, odor, and flavor produced by beef from bulls and heifers of the Pirenaica and Friesian breeds were studied during 7 d of aging. The Friesian breed beef had stronger fatty flavor and aftertaste than the Pirenaica, as well as differences in the content of several volatile compounds. Bull beef had stronger liver-like odor and flavor, and bloody flavor that were related to a higher 2-propanone content, while beef from heifers had stronger characteristic flavor. Aging of meat increased characteristic flavor and aftertaste. Ethanal showed a positive correlation with livery flavor and a negative correlation with the characteristic odor. The hexane seems to contribute to fatty flavor, 2-propanone was related to livery and bloody notes, and 2,2,4,6,6-pentamethylheptane to characteristic flavor. [source] Insoluble Grape Material Present in Must Affects the Overall Fermentation Aroma of Dry White Wines Made from Three Grape Cultivars Cultivated in GreeceJOURNAL OF FOOD SCIENCE, Issue 1 2002S. Karagiannis ABSTRACT: Musts from 3 grape varieties were used to elucidate the effect of the presence of grape solids in must on the volatile composition of the resultant white wines. Volatile compounds were analyzed by GC/MS and GC/FPD except H2S, which was measured spectrophotometrically. Increasing quantities of grape insoluble material decreased the substances that enhanced aroma of Savatiano and Batiki wines. Simultaneously, the levels of compounds that degrade wine aroma, when formed in large amounts, were increased. However, in Muscat of Hamburg wines, the levels of some volatiles were not influenced by must turbidity in the same way as in wines of the other cultivars. [source] Headspace Evaluation of Methanethiol and Dimethyl Trisulfide in Aqueous Solutions of Soy-protein IsolatesJOURNAL OF FOOD SCIENCE, Issue 5 2000W.L. Boatright ABSTRACT Volatile compounds from 2 samples of aqueous soy-protein isolates (SPI) (7%) were analyzed using both static and dynamic headspace methods. Based on dynamic headspace analyses, the most powerful odorants were (1) dimethyl trisulfide, (2) methanethiol, (3) hexanal, (4) an unidentified charred, sweaty feet-like odor, (5) 2-pentyl furan, (6) 2,3-butadione, and (7) an unknown burnt-like odor. The most powerful odorants by static headspace analyses were (1) dimethyl trisulfide, (2) hexanal, (3) methanethiol, and (4) 2-pentyl furan. Using deuterium labeled DMTS as an internal standard, DMTS was quantified at 60.1 and 45.5 ppb in the SPIs. This corresponds to odor values of 6014 and 4554, respectively. Using a cool, on-column technique, direct injection of concentrated-headspace volatiles and solvent-recovered volatiles with an internal standard of d6 -DMTS detected both methanethiol and DMTS at similar levels as with the traditional injection methods. [source] SPME , A valuable tool for investigation of flower scentJOURNAL OF SEPARATION SCIENCE, JSS, Issue 8 2003Petr Barták Abstract A novel Headspace Solid Phase Microextraction (HS-SPME) protocol is proposed for the analysis of floral scent. Volatile compounds emitted from the flower are collected on a Carboxen/PDMS fiber for 1 hour, transferred to the GC, and analyzed by GC/MS. The method completely eliminates the use of organic solvents, does not require special instrumentation, and may readily be performed in the field without access to mains electricity and other energy supplies. The method is robust, sensitive, and reduces the sampling stress on the investigated plant. Since enzymatic reactions in living flowers may cause changes in the composition of emitted fragrance, dried rosemary (Rosmarinus officinalis L.) was used as a stable standard for the method development and optimization. In addition, grape wine was also suggested as homogeneous, bio-compatible, and relatively stable standard of pronounced and typical scent for the same purpose. The optimized method was used for the comparative investigation of the fragrances emitted by two different species , Lathyrus vernus (L.) and Orchis pallens (L.). Several monoterpenes (C10 compounds) were found as the main fragrance components of lathyrus, while sesquiterpenes (C15 compounds) were typical for the orchid. [source] Effect of Saccharomyces cerevisiae F12 on volatile compounds in wines at three different stages of industrial biological ageingAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2008D. MUÑOZ Abstract Background and Aims: Wines subjected to biological ageing for variable lengths of time were inoculated with Saccharomyces cerevisiae F12 and were microaerated in order to reduce their overall ageing time. Methods and Results: Volatile compounds as determined by gas chromatography (GC) and GC,mass spectrometry (MS) were grouped according to their aroma descriptors into nine odourant classes, which exhibited similar changes in wines obtained by traditional ageing, and in others inoculated with S. cerevisiae F12 and microaerated. A tasting panel found the wine previously aged for 2 years and inoculated with S. cerevisiae F12 to be of better quality than the identical wine subjected to no inoculation. Conclusion: Based on the results, the ageing time for wines previously aged under typical winery conditions for 0 and 2 years can be shortened by the inoculation of S. cerevisiae F12 flor yeasts. Significance of the Study: The biological ageing system used allows the production cost of fino wines to be reduced by shortening the ageing process. [source] Liquid,vapour partition of ethanol in bakery productsFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2006Paola Pittia Abstract Ethanol is a common ingredient in formulated foods, naturally present or added in liquid form in order to achieve the desired sensorial properties. In many complex foods this volatile compound could also serve interesting technological functions, as well as extending their shelf-lives, owing to its capacity to inhibit or reduce the rate of microbial growth. At the European level there are no known restrictions regarding the use of ethanol in foods as a preservative, while in Italy, current regulations allow its addition as an anti-moulding agent in pre-packed bread, at a maximum concentration of 2% on a dry weight basis. This research studied the effect of water activity (aw) and water content on the ethanol vapour pressure of sliced white bread, previously equilibrated at various aw values and with 2% ethanol added. Different aw values were obtained by both rehydration from previously freeze-dried bread, and dehydration from the fresh product. The results showed that both aw and moisture affected the vapour pressure of ethanol as a consequence of water,solute and ethanol,solute interactions in the matrix. These interactions varied according to the modality of equilibration (desorption or absorption) at a given aw. The results are discussed in terms of ethanol activity (ae), computed as the ratio between the ethanol vapour pressure in bread and the vapour pressure of pure ethanol at the same temperature. This index, analogous to aw, proved to be useful in evaluating the ,freedom' of the ethanol present in a food matrix to be released in the vapour phase. Copyright © 2006 John Wiley & Sons, Ltd. [source] Probiotic buttermilk-like fermented milk product development in a semiindustrial scale: Physicochemical, microbiological and sensory acceptabilityINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2009ADRIANE E C ANTUNES Probiotic buttermilk-like fermented milk in different flavors in versions with sucrose and sucralose were processed in a pilot plant. The Mesophilic Aromatic Culture CHN-22 and Bifidobacterium animalis Bb12 were the cultures employed for fermentation. Physicochemical composition, apparent viscosity, diacetyl content, viability of cultures during storage, and acceptance of product via sensorial analysis were assessment factors. The high viability of the probiotic culture was observed (average 8.08 log cfu/ml) during refrigerated storage (28 days) of buttermilk and good acceptance of the product via sensory test. However, the probiotic culture might have been responsible for the loss of diacetyl, a volatile compound that is a characteristic feature of the product. [source] | ||||||||||||||||||||||||||||||||||||||||