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PubMed2004

Identification and sensory evaluation of volatile compounds in oxidized porcine liver.

Headspace solid phase microextraction (HS-SPME) was used to isolate the off-flavor volatile compounds, which are formed during the oxidation of porcine liver induced by iron. Poly(dimethylsiloxane)/divinylbenzene fiber was used in the HS-SPME. Changes in the volatile compounds of oxidized porcine liver and unsaturated fatty acids induced by iron were examined. Results showed that 1-octen-3-one (metallic), hexanol (weak metallic), 1-octen-3-ol (mushroomlike), (E)-2-nonenal (cardboardlike), and (E,E)-2,4-decadienal (fatty, oily) were the main contributors to the overall off-flavor of porcine liver. The results of the sensory evaluation revealed that oxidized arachidonic acid has a major impact on metallic and liverlike off-flavor and that when liverlike off-flavor is perceived, metallic is also included. Oxidized linolenic acid was the most important contributor to the objectionable fishy off-flavor. Oxidized porcine liver exhibited distinct metallic, liverlike, and weak fishy background notes. Liverlike flavor had a high correlation coefficient with odor characteristics such as metallic (0.839) and fishy (0.777). In this study, it was clearly observed that the stronger the metallic and fishy off-flavor the higher the perception of liverlike off-flavor.

Animals↗
PubMed2004

Optimization of dynamic headspace extraction of the edible red algae Palmaria palmata and identification of the volatile components.

A new extraction method was applied to the volatile compounds of Palmaria palmata. Dynamic headspace was optimized according to an experimental design, and descriptive sensory analysis and intensity and similarity tests were performed for each extract to assess their respective representativeness. Results showed that extract obtained with crushed algae after a 30 min purge was the most representative. GC-MS analysis was then performed on this extract to identify the volatile components. Seven halogenated compounds, seven aldehydes, two ketones, three alcohols, and four miscellaneous compounds were identified. Among them, halogenated compounds were the most characteristic of red algae, and more particularly, iodoethane and iodopentane, which had yet been found in other seaweeds.

Aldehydes↗
PubMed2003

On-line gas chromatography combustion/pyrolysis isotope ratio mass spectrometry (HRGC-C/P-IRMS) of pineapple (Ananas comosus L. Merr.) volatiles.

By use of extracts prepared by liquid-liquid separation of the volatiles from self-prepared juices of pineapple fruits (Ananas comosus) (n = 14) as well as commercial pineapple recovery aromas/water phases (n = 3), on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta(13)C(VPDB) and delta(2)H(VSMOW) values of selected pineapple flavor constituents. In addition to methyl 2-methylbutanoate 1, ethyl 2-methylbutanoate 2, methyl hexanoate 3, ethyl hexanoate 4, and 2,5-dimethyl-4-methoxy-3[2H]-furanone 5, each originating from the fruit, the delta(13)C(VPDB) and delta(2)H(VSMOW) data of commercial synthetic 1-5 and "natural" (biotechnologically derived) 1-4 were determined. With delta(13)C(VPDB) data of pineapple volatiles 1-4 varying from -12.8 to -24.4 per thousand, the range expected for CAM metabolism was observed. Compound 5 showed higher depletion from -20.9 to -28.6 per thousand. A similar situation was given for the delta(2)H(VSMOW) values of 3-5 from pineapple ranging from -118 to -191 per thousand, whereas 1 and 2 showed higher depleted values from -184 to -263 per thousand. In nearly all cases, analytical differentiation of 1-5 from pineapple and natural as well as synthetic origin was possible. In general, natural and synthetic 1-5 exhibited delta(13)C(VPDB) data ranging from -11.8 to -32.2 per thousand and -22.7 to -35.9 per thousand, respectively. Their delta(2)H(VSMOW) data were in the range from -242 to -323 per thousand and -49 to -163 per thousand, respectively.

Ananas↗
PubMed2003

Effect of gluconic acid consumption during simulation of biological aging of sherry wines by a flor yeast strain on the final volatile compounds.

Flor yeast Saccharomyces cerevisiae (capensis G1) strain assimilates gluconic acid during the aerobic biological aging process of sherry wines and exerts significant changes on the final volatile compounds of wines, especially a decrease in volatile acidity and butanoic, isobutanoic, 2-methylbutanoic, and 3-methylbutanoic acids. This decrease may have a favorable effect on the quality of sherry wines.

Butyrates↗
PubMed2003

Modification of volatile compound profile of virgin olive oil due to hot-water treatment of olive fruit.

The effect of hot-water treatments of olive fruits before processing on the biosynthesis of virgin olive oil aroma was investigated by quantifying the variation within the major classes of volatile compounds. Data showed that hot-water treatments gave rise to changes in the volatile aroma profile of virgin olive oil from the three olive cultivars under study, Manzanilla, Picual, and Verdial. Different effects by thermal treatments were observed according to cultivar. In general, these changes are mainly due to a decrease in the contents of C(6) aldehydes and C(5) compounds. Contents of C(6) alcohols and esters remained constant or decreased slightly when the temperature of the treatment was increased. Thus, heat treatments seemed to promote a partial deactivation of the lipoxygenase/hydroperoxide lyase enzyme system, whereas other enzymatic activities, within the lipoxygenase pathway, such as alcohol dehydrogenase and alcohol acyltransferase, remained apparently unaffected as a consequence of heat treatments.

Alcohols↗
PubMed2003

Correlations between pulp properties of eucalyptus clones and leaf volatiles using automated solid-phase microextraction.

Analysis of biogenic volatile organic compounds (BVOC) of 14 Eucalyptus clones has been performed using an automated headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography (GC)/ion trap mass spectrometry (ITMS) method. Correlations between pulp properties of Eucalyptus clones and the BVOC of their leaf headspaces were studied. The compounds alpha-terpineol and the sesquiterpene beta-eudesmol were positively correlated with S5, a property related to the hemicelluose content in the pulp. Qualitative results obtained with automated HS-SPME were sufficient to group together the same species and related hybrids through cluster analysis and were confirmed through principal component analysis. A preliminary separation of the essential oils of Eucalyptus dunnii through comprehensive two-dimensional gas chromatography (GC x GC) showed approximately 580 peaks compared to approximately 60 in a typical GC/ITMS first-dimension chromatogram. The potential of HS-SPME coupled to GC x GC to improve the separation of Eucalyptus volatiles and other plant essential oils looks extremely promising for new applications of unsupervised learning methods.

Autoanalysis↗
PubMed2004

Characterization of Fuji apples from different harvest dates and storage conditions from measurements of volatiles by gas chromatography and electronic nose.

Volatile compounds in Fuji apples harvested at two different maturities were measured at harvest and after 5 and 7 months of cold storage (1 degrees C) in four different atmospheres. When the samples were characterized by both chromatographic measurements of volatiles and responses of an electronic nose, the analyses showed a clear separation between fruits from different storage conditions (a normal cold atmosphere and three controlled atmospheres). During poststorage, the apples were left to ripen for 1, 5, and 10 days at 20 degrees C before analytical measurements were done involving headspace-gas chromatography methods and electronic nose type quartz crystal microbalances. Electronic nose responses registered by seven different sensors were used to classify the apples using principal component analysis. It was possible to identify the samples from different storage periods, days of shelf life, and harvest dates, but it was not possible to differentiate the fruits corresponding to different cold storage atmospheres.

Chromatography, Gas↗
PubMed2004

Off-vine grape drying effect on volatile compounds and aromatic series in must from Pedro Ximénez grape variety.

Changes in 36 volatile compounds of must from ripe grapes dried by direct exposure to sun and must from ripe grapes were studied. Compounds not dependent on sampling site in both musts were selected, and their concentration/Brix degree ratio values, were subjected to variance analysis. Only butan-1-ol and isoamyl alcohols showed no differences, while (E)-hex-3-en-1-ol, (Z)-hex-3-en-1-ol, (E)-hex-2-en-1-ol, (E)-hex-2-enal, hexanoic acid, isobutanol, benzyl alcohol, 2-phenylethanol, gamma-butyrolactone, gamma-hexalactone, and 5-methylfurfural, showed significant differences between the two must types, which may be ascribed to the drying process. An approach to describe must odor has been carried out by grouping volatile compounds in aromatic series, increasing their values in the fruity, solvent, sweet, and roasted series and diminishing the herbaceous as a consequence of the drying process.

Desiccation↗
PubMed2004

Influence of lambda-carrageenan on the release of systematic series of volatile flavor compounds from viscous food model systems.

The effect of lambda-carrageenan addition level (0.1, 0.25, 0.4, and 0.5% w/w) and viscosity on the release of systematic series of aroma compounds (aldehydes, esters, ketones, and alcohols) was studied in thickened viscous solutions containing lambda-carrageenan and 10 wt % of sucrose. Air-liquid partition coefficients K (37 degrees C) of a total of 43 aroma compounds were determined in pure water and in the lambda-carrageenan solutions by static headspace gas chromatography. Mass transfer of the aroma compounds in water and in the thickened lambda-carrageenan solutions which had a wide viscosity range was assessed by dynamic headspace gas chromatography. K (37 degrees C) increased as the carbon chain increased within each homologous series. Esters exhibited the highest volatility, followed by aldehydes, ketones, and alcohols. Under equilibrium, no overall effect of lambda-carrageenan was found, except with the most hydrophobic compounds. Analysis of flavor release under nonequilibrium conditions revealed a suppressing effect of lambda-carrageenan on the release rates of aroma compounds, and the extent of decrease in release rates was dependent on the physicochemical characteristics of the aroma compounds, with the largest effect for the most volatile compounds. However, none of the effects was of a magnitude similar to the obtained changes in the macroscopic viscosity, and the suppressing effects are therefore attributable to the thickener and not the physical properties of the increasingly viscous systems.

Alcohols↗
PubMed2004

Identification of trace volatile compounds in freshly distilled Calvados and Cognac using preparative separations coupled with gas chromatography-mass spectrometry.

Gas chromatography coupled with mass spectrometry (GC-MS) using both electron impact and chemical ionization detection modes led to the determination of the volatile composition of two samples of freshly distilled Cognac and two samples of freshly distilled Calvados. A total of 169 volatile compounds were directly identified in dichloromethane extracts obtained by liquid-liquid extraction. Trace compounds present in both spirits were characterized with the help of preparative separations. In a first step, groups of compounds were separated by preparative GC, and the fractions were analyzed on a polar stationary phase by GC-MS. In a second step, silica gel fractionation was used to separate them by polarity. In this study, 331 compounds, of which 162 can be considered as trace compounds, were characterized in both freshly distilled Cognac and Calvados. Of these, 39 are common to both spirits; 30 are specific to Cognac with numerous hexenyl esters and norisoprenoidic derivatives, whereas 93 are specific to Calvados with compounds such as unsaturated alcohols, phenolic derivatives, and unsaturated aldehydes.

Alcoholic Beverages↗
PubMed2004

Some unusual minor volatile components of tomato.

The identities and possible origins of three minor unusual volatile components of tomato are discussed. These are pentyl nitrate, the first identification of a volatile alkyl nitrate in a fresh vegetable or fruit; 5-ethyl-2(5H)-furanone, which, besides its presence in tomato, was found to be a major autoxidation product of pure (Z)-3-hexenal; and 5-ethylcyclopentene-1-carbaldehyde, a likely unusual linolenic acid oxidation product.

Aldehydes↗
PubMed2005

Glycosidically bound volatiles and flavor precursors in Laurus nobilis L.

Glycosidically bound volatile compounds in different parts (leaves and buds) of Laurus nobilis L. were investigated. After isolation of extracts obtained by Amberlite XAD-2 adsorption and methanol elution, glycosides were analyzed after enzymatic hydrolysis by GC-MS or directly after trifluoroacetyl (TFA) derivatization by GC-MS in EI and NCI mode. In the leaves most of the glycosidically bound volatiles occur as beta-D-glucopyranosides. Among the disaccharides, primeverosides are predominant; smaller amounts of alpha-L-arabinofuranosyl-beta-D-glucopyranosides, rutinosides, and vicianocides could also be identified. Major aglycons comprised benzyl alcohol, some linalool-diols, 2-hydroxy-1,8-cineole and its derivatives such as 2,3-dehydro-1,8-cineole, sobrerols, and menthadien-8-ols. Among the identified nor-carotenoids, 3-oxo-alpha-ionol, the corresponding 7,8-dihydro derivative, and vomifoliol are predominant in leaves. 3-Hydroxy-beta-damascone and 3-hydroxy-7,8-didehydro-beta-ionol, precursors of the sensorially active damascenone, were identified only in the buds.

Flowers↗
PubMed2005

Changes in volatile emissions from apple trees and associated response of adult female codling moths over the fruit-growing season.

Odors in the headspace of apple trees were characterized by in situ volatile collections in the orchard. Sixty-two compounds were quantitatively identified with thermal desorption-gas chromatography-mass spectrometry over the complete fruit-growing season. Overall quantities in the headspace of fruit-bearing twig were highest at petal fall and at the beginning of June and August. Interestingly, the latter two periods coincide with the flight maxima of the codling moth, Cydia pomonella, one of the principal pest insects of apple fruit worldwide. Dual-choice bioassays with mated adult female moths in a Y-tube olfactometer showed that the blend of plant-derived volatiles repelled this key pest of apple at petal fall and attracted it from July to mid-August. Single-component analysis indicated that benzaldehyde and butyl acetate might contribute to the observed repellent effect, but the constituents accounting for the attractant effect mid-season remain to be further elucidated. The attractant effect clearly originates from the apple fruit and not from the twig with leaves, as bioassays demonstrated conclusively.

Animals↗
PubMed2004

Volatile flavor analysis and sensory evaluation of custard desserts varying in type and concentration of carboxymethyl cellulose.

The influence of type and concentration of carboxymethyl cellulose (CMC) on flavor and textural properties of custard desserts was examined. A synthetic strawberry flavor mixture was used to flavor the custards; it comprised 15 volatile flavor compounds. The viscosity of the custards was determined using rheometric measurements. Static headspace gas chromatography and in-nose proton transfer reaction-mass spectrometry analyses were conducted to determine the custards' volatile flavor properties. Perceived odor, flavor, and textural properties were assessed in sensory analysis experiments using magnitude estimation against a fixed modulus. Both type and concentration of CMC altered the viscosity of the custards. Softer custards had higher static headspace flavor concentrations. On the contrary, firmer custards demonstrated higher in-nose flavor concentrations. In sensory analysis, firmer custards showed higher thickness and lower sweetness intensities than their low-viscosity counterparts. The thickness perception corresponded to the viscosity of the custards. Removal of sucrose from the custards affected sweetness intensity only and not the intensity of other attributes. Therefore, the influence of the viscosity of the custards on the release of sweet-tasting components is held responsible for the effect on perceived sweetness intensity. Odor intensities were generally higher for the low-viscosity custard, whereas fruity flavor intensities were higher for the firmer custards. Odor intensities correlated with static headspace concentrations and flavor intensities related reasonably well with in-nose concentrations. Opening and closing of the nasal cavity is regarded as an important factor determining the discrepancy between static and in-nose measurements.

Carboxymethylcellulose Sodium↗
PubMed2005

Uncertainty analysis of a dynamic vapor sorption-fast gas chromatography-flame ionization detection method for the rapid analysis of volatile release from glassy matrices.

Uncertainty analysis was conducted with a dynamic vapor sorption-fast gas chromatography-flame ionization detection (DVS-fast GC-FID) method, developed to rapidly analyze the extent of volatile release that occurs from carbohydrate glasses due to humidification and temperature increases. Triplicate samples progressed through a two-step special automatic operation method in the DVS. Samples were exposed to relative humidities ranging from 40 to 90% (in 10% increments) at 15, 25, and 35 degrees C. Uncertainty analysis shows that the DVS-fast GC-FID method uncertainty is smaller than the natural sample uncertainty, indicating that the variability in a sample's physical properties has a dominant impact on the overall uncertainty of the volatile retention results obtained using the DVS-fast GC-FID method. Uncertainty analysis also indicates that the variance associated with the mass of benzaldehyde measured by the DVS-fast GC-FID is the largest contributor to the overall benzaldehyde retention variance when the cumulative mass of benzaldehyde measured is small.

Adsorption↗
PubMed2005

Development and validation of a dynamic vapor sorption-fast gas chromatography-flame ionization detection method for rapid analysis of volatile release from glassy matrices.

Historically, saturated salt solutions in desiccators have been used to investigate the effects of increasing relative humidity and temperature on the volatile retention efficiency of amorphous glasses. Obtaining data using desiccators is a static process that gives the researcher discrete data points with which to draw conclusions. Dynamic vapor sorption (DVS; SMS, London, U.K.) is a humidification system that creates specific relative humidity and temperature environments within a chamber that contains the material being investigated. This study had two specific aims: (1) to develop a DVS-fast GC-FID method that dynamically evaluates the effects of humidification and temperature increases on volatile release from amorphous carbohydrate glasses and (2) to evaluate the validity of the DVS-fast GC-FID method. Artificial cherry Durarome (Firmenich, Plainsboro, NJ) was used as the model system. The DVS-fast GC-FID method proved to be an innovative, accurate, and precise technique that can be used to conduct humidification/temperature-volatile release studies.

Benzaldehydes↗
PubMed2004

Hydrolysis of glycosidically bound volatiles from apple leaves (Cv. Anna) by Aspergillus niger beta-glucosidase affects the behavior of codling moth (Cydia pomonella L.).

Glycosidically bound volatiles released from apple leaf extracts (cv. Anna) were analyzed by solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) and their behavioral effects on codling moth (CM) adults were evaluated in cage bioassays. The levels of 1-octanol, linalool, geraniol, benzyl alcohol, methyl salicylate, (2R,5R)-theaspirane, and (2S,5R)-theaspirane were significantly increased in the leaf extracts containing the Aspergillus niger beta-glucosidase (BGL1) compared to the extracts containing the glucoimidazole. The attractiveness of individual compounds to CM adults was found in the following decreasing order: methyl salicylate and mixture of two theaspirane isomers, followed by linalool and benzyl alcohol. Geraniol was found to be repellent to CM adults. The addition of geraniol (39.4 ng mL(-1)) to any of the individual volatiles or to a mixture of these attractants eliminated their attractiveness. Our data suggest the possible application of geraniol as a repellent and methyl salicylate or theaspiranes as attractants for the integrated control of CM in apple orchards.

Acyclic Monoterpenes↗
PubMed2005

Effects of nucleo-cytoplasmic interactions on leaf volatile compounds from citrus somatic diploid hybrids.

Three diploid citrus somatic hybrids (cybrids) were produced by fusions combining nucellar callus-derived protoplasts of Willow Leaf mandarin (Citrus deliciosa Ten.) and Commune clementine (Citrus clementina Hort. ex Tan.) with, respectively, leaf protoplasts of Eureka lemon [Citrus limon (L.) Burm.] and Marumi kumquat [Fortunella japonica (Thunb.) Swing.] and leaf protoplasts of Marumi kumquat. Ploidy and origins of the nuclear, chloroplastic, and mitochondrial genomes were investigated by flow cytometry and nuclear and cytoplasmic simple sequence repeat analyses. Volatile compounds were extracted from the leaves of the three cybrids by a pentane/ether (1:1) mixture, analyzed by GC-MS, and compared to those of their parents. The cybrids were found to be very close to their nucleus-giving parent, suggesting that the main information for volatile compounds biosynthesis is contained in the nucleus. However, nucleo-cytoplasmic interactions occurred: the (mandarin + lemon) cybrid, possessing nucleus and chloroplasts of lemon and mitochondria from mandarin, synthesizes more monoterpene alcohols and esters than its nucleus-giving parent; the (clementine + kumquat) cybrid, possessing nucleus from kumquat and organelles from mandarin, synthesizes more monoterpene and sesquiterpene hydrocarbons and sesquiterpene alcohols than its nucleus-giving parent.

Cell Nucleus↗