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PubMed2002

Analysis of volatiles from Spanish honeys by solid-phase microextraction and gas chromatography-mass spectrometry.

Headspace solid-phase microextraction (SPME), followed by gas chromatography (GC)-mass spectrometry (MS) determination, has been used for the analysis of honey volatiles. Two SPME fibers were employed to study the composition of volatiles from various types of Spanish honeys. The best results were obtained with the Carboxen/PDMS fiber, using a homogenization time of 1 h at 70 degrees C and a sampling period of 30 min. A total of 35 compounds were detected, most of them identified by GC-MS and quantified using external standards. Differences in the composition of honey volatiles were obtained, and these results allowed the differentiation of honeys. However, further studies are necessary to confirm the utility of this technique as an alternative tool for the characterization of the floral origin of honeys.

Citrus↗
PubMed2002

Effect of drying method on the volatiles in bay leaf (Laurus nobilis L.).

The effect of different drying treatments on the volatiles in bay leaf (Laurus nobilis L.) was studied. Simultaneous distillation extraction (SDE) and solid-phase microextraction (SPME) were compared by gas chromatography-mass spectrometry (GC-MS) of the volatile components in bay leaves. SDE yielded better quantitative analysis results. Four drying treatments were employed: air-drying at ambient temperature, oven-drying at 45 degrees C, freezing, and freeze-drying. Oven drying at 45 degrees C and air-drying at ambient temperature produced quite similar results and caused hardly any loss in volatiles as compared to the fresh herb, whereas freezing and freeze-drying brought about substantial losses in bay leaf aroma and led to increases in the concentration levels of certain components, e.g., eugenol, elemicin, spathulenol, and beta-eudesmol.

Desiccation↗
PubMed2002

Effect of 1-methylcyclopropene on volatile emission and aroma in cv. Anna apples.

The rapidly ripening summer apple cultivar Anna was treated with 0.1 micro L(-1) and 1 microL L(-1) 1-methylcyclopropene (MCP) at harvest and kept at 20 degrees C, or stored for 5 weeks at 0 degrees C and then transferred to 20 degrees C. Total volatiles were not reduced by treatment with 0.1 microL L(-1) MCP, but were 70% lower in fruits treated with 1 microL L(-1) MCP than in untreated fruits. Ethylene production was 50% and 95% inhibited by 0.1 microL L(-1) and 1 microL L(-1) MCP, respectively. The volatiles produced by fruit at harvest were predominantly aldehydes and alcohols, with some acetate esters as well as 2-methyl butyl acetate and beta-damascenone. During ripening, the acetate and butyrate esters increased greatly and alcohols and aldehydes decreased. MCP-treated apples retained more alcohols, aldehydes, and beta-damascenone volatiles than did untreated apples. Sensory evaluation found that control and 0.1 microL L(-1) treated apples developed more fruity, ripe, and overall aromas, but the preference was for the 1 microL L(-1) treated apples with a less ripe aroma.

Alcohols↗
PubMed2002

Effect of different strains of Saccharomyces cerevisiae on production of volatiles in Napa Gamay wine and Petite Sirah wine.

Napa Gamay grapes were fermented with four different strains of the yeast Saccharomyces cerevisiae (VL1, MI16, Fermirouge, and RA17). Petite Sirah grapes were fermented with seven different strains of the same yeast (BM45, Fermirouge, RA17, NI, CX3079, A350, and A796). Volatile compounds formed in the wines were analyzed by gas chromatography/mass spectrometry. Volatile compounds found in both wines were alcohols, esters, and acids, as well as some miscellaneous compounds. Isoamyl alcohol was the compound found in the highest relative amount with all four yeast strains in the Napa Gamay wines, followed by 2-phenyl ethanol, monoethyl succinate, and hexanoic acid. The relative amounts of isoamyl alcohol ranged from 30.84% (VL1) to 43.28% (RA17). Major volatile compounds found in Petite Sirah wines were isoamyl alcohol, 2-phenyl ethanol, 2-hydroxy ethyl propanoate, monoethyl succinate, and octanoic acid. The several esters, including 2-hydroxyethyl propanoate, may contribute to the fruity flavor of Petite Sirah wines. Overall, the S. cerevisiae yeast strains used to ferment Napa Gamay grapes and Petite Sirah grapes produced the same major components, with certain variations in formation levels.

Acids↗
PubMed2002

Changes in the volatile compounds and in the chemical and physical properties of snake fruit (Salacca edulis Reinw) Cv. Pondoh during maturation.

During the maturation of snake fruit (Salacca edulis Reinw) Pondoh, the contents of sucrose, glucose, fructose, and volatile compounds changed drastically. The glucose, fructose, and volatile compounds contents showed their maximum levels at the end of maturation; however, the sucrose content decreased. During maturation, the flesh firmness tended to increase; however, at the end of maturation (6 months), the flesh became soft. The major volatile aroma in solvent-assisted flavor evaporation (SAFE) and solvent extracts were identified to be methyl esters of butanoic acids, 2-methylbutanoic acids, hexanoic acids, pentanoic acids, and the corresponding carboxylic acids. Furaneol (4-hydroxy-2,5-dimethyl-3(2H)-furanone) was also identified as a minor aroma constituent in the SAFE residue. The methyl esters were found to increase dramatically during stages 4-6 (5-6 months after the pollination) to exceed the amounts of carboxylic acids, whereas the acid amount increased gradually until stage 5 (5.5 months after the pollination) to reach the maximum at stage 6 (6 months after the pollination).

Arecaceae↗
PubMed2003

Role of certain volatile thiols in the bouquet of aged champagne wines.

A method for the specific extraction of volatile thiols by use of p-hydroxymercuribenzoate has made it possible to identify certain flavor-active volatile thiols in Champagne wines. Benzenemethanethiol, 2-furanmethanethiol, and ethyl 3-mercaptopropionate were present in these wines at concentrations considerably higher than their perception thresholds. Their concentrations increased gradually in proportion to the bottle aging period and sharply as a result of disgorging. The contribution of these volatile thiols to the empyreumatic nuances of the bouquet of aged Champagne wines was demonstrated for the first time.

3-Mercaptopropionic Acid↗
PubMed2003

Volatiles from leaves, fruits, and virgin oil from Olea europaea Cv. Olivastra Seggianese from Italy.

The volatiles produced by leaves and fruits of Olea europaea cv. Olivastra Seggianese have been analyzed in two different phenological stages. Furthermore, the volatiles of the virgin olive oil obtained from ripe fruits has been characterized. The volatiles were sampled by means of two different techniques: hydrodistillation and SPME. Differences were observed between the two different collection times, the different organs, and sampling techniques. The major constituents were often aldehydes, particularly (E)-2-hexenal (9.8-48.0%); however, also many terpenoids have been identified, mainly (E,E)-alpha-farnesene (0.2-27.0%), linalool (0-3.6%), beta-caryophyllene (0-8.1%), and valencene (0-2.5%). This is the first investigation on this cultivar.

Aldehydes↗
PubMed2002

Determination of antioxidant potential of volatile extracts isolated from various herbs and spices.

Antioxidant activities of volatile extracts isolated from thyme, basil, rosemary, chamomile, lavender, and cinnamon were evaluated by two independent assays: the aldehyde/carboxylic acid assay and the conjugated diene assay. The volatile extracts were prepared from dried herbs and spices using liquid-liquid continuous extraction following steam distillation under reduced pressure (55 degrees C and 95 mmHg). The antioxidant activities of the extracts decreased in the following order in both of the lipophilic assay systems: thyme > basil > rosemary > chamomile > lavender and cinnamon. Thyme and basil extracts inhibited the oxidation of hexanal for 40 days at the levels of 10 microg/mL and 50 microg/mL, respectively. The extracts of thyme and basil were effective in retarding methyl linoleate deterioration at 40 degrees C, with activity increasing with concentration in the range 10-200 microg/mL. At a concentration of 50 microg/mL, thyme extract was similar in antioxidant activity to BHT and alpha-tocopherol in the conjugated diene assay. The antioxidant potentials of the volatile extracts used in this study were accurately measured by the lipophilic systems, such as the aldehyde/carboxylic acid assay and the conjugated diene assay.

Antioxidants↗
PubMed2003

Study of light-induced volatile compounds in goat's milk cheese.

Light-induced volatile compounds in goat cheese were studied by a combination of solid phase microextraction (SPME)-gas chromatography (GC)-mass spectrometry (MS), headspace oxygen depletion, and sensory evaluation. Samples stored under fluorescent light for 2 days at 30 degrees C had 90% more volatile compounds and 4 times more headspace oxygen depletion than samples stored in the dark at 30 degrees C. The volatiles 1-heptanol, heptanal, nonanal, and 2-decenal were formed and increased only in the light-stored samples, which may be formed from singlet oxygen oxidation of unsaturated fatty acids. Sensory evaluation showed that samples stored under light had significantly more off-flavor than samples stored in the dark at 30 degrees C (P < 0.05), and 1-heptanol, heptanal, nonanal, and 2-decenal increased the goat cheese off-flavor significantly (P < 0.05).

Aldehydes↗
PubMed2003

Evolution of volatile byproducts during wine fermentations using immobilized cells on grape skins.

A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Repeated batch fermentations were conducted using this biocatalyst as well as free cells, at 25, 20, 15, and 10 degrees C. Solid phase microextraction (SPME) was used in monitoring the evolution of volatile byproducts. The effect of immobilization and temperature on evolution patterns of volatiles was obvious. The major part of esters was formed after consumption of 40-50% of the sugars. Similar processes were observed for amyl alcohols and 2-phenylethanol, whereas 1-propanol and 2-methyl-1-propanol were formed during the whole alcoholic fermentation period at an almost constant formation rate. Acetaldehyde and acetoin were synthesized in the early stages of fermentation. Afterward, their amount decreased. In most cases, immobilized cells exhibited higher formation rates of volatiles than free cells. The final concentration of esters was higher in wines produced by immobilized biocatalyst. Their amount increased with temperature decrease. The opposite was observed for higher alcohols.

Acetaldehyde↗
PubMed2003

Volatile compounds of wines produced by cells immobilized on grape skins.

A biocatalyst was prepared by immobilization of Saccharomyces cerevisiae cells on grape skins. Repeated batch fermentations were conducted using the immobilized biocatalyst as well as the free yeast cells at 25, 20, 15, and 10 degrees C. The major volatile byproducts were determined by GC, whereas the minor volatile constituents were extracted in dichloromethane and analyzed by HRGC-MS. The qualitative profiles of the wines produced were similar in every case. Immobilized cells gave wines with higher contents of ethyl and acetate esters that increased with temperature decreases from 25 to 15 degrees C. The amount of volatile alcohols was more pronounced in wines produced by free cells and decreased dramatically at low fermentation temperatures (10 degrees C).

1-Propanol↗
PubMed2003

Changes in the polyphenolic and volatile contents of "fino" sherry wine exposed to ultraviolet and visible radiation during storage.

Experiments of accelerated oxidation of "fino" sherry wines have been conducted at 25 degrees C and under the influence of UV-visible radiation (a xenon lamp of 1500 W). With the aim of determining the contribution of UV-vis radiation to the browning phenomenon, two types of glass bottles were employed: topaz bottles (with low values of transmittance in the UV-visible range) and transparent bottles. To identify significant differences between the wine before and after being subjected to the influence of the UV-vis radiation, the values of absorbance at 420 nm and the concentrations of various polyphenolic and volatile compounds were submitted to a multivariate variance analysis. Both factors considered (time and type of bottle) had a statistically significant effect on the values of absorbance at 420 nm and on the concentration of most of the polyphenolic compounds, whereas only the "time" factor was significant for volatile compounds. All wines showed losses in several polyphenolic compounds, which were more severe for the wines bottled in transparent glasses. However, these wines exhibited a lower degree of visual browning (abs 420 nm). In the case of volatile compounds, most of these presented increases during storage exposed to the influence of the UV-vis radiation.

Alcohols↗
PubMed2003

Leaf volatile compounds of seven citrus somatic tetraploid hybrids sharing willow leaf mandarin (Citrus deliciosa Ten.) as their common parent.

Volatile compounds were extracted by a pentane/ether (1:1) mixture from the leaves of seven citrus somatic tetraploid hybrids sharing mandarin as their common parent and having lime, Eurêka lemon, lac lemon, sweet orange, grapefruit, kumquat, or poncirus as the other parent. Extracts were examined by GC-MS and compared with those of their respective parents. All hybrids were like their mandarin parent, and unlike their nonmandarin parents, in being unable to synthesize monoterpene aldehydes and alcohols. The hybrids did retain the ability, although strongly reduced, of their nonmandarin parents to synthesize sesquiterpene hydrocarbons, alcohols, and aldehydes. These results suggest that complex forms of dominance in the mandarin genome determine the biosynthesis pathways of volatile compounds in tetraploid hybrids. A down-regulation of the biosynthesis of methyl N-methylanthranilate, a mandarin-specific compound, originates from the genomes of the nonmandarin parents. Statistical analyses showed that all of the hybrids were similar to their common mandarin parent in the relative composition of their volatile compounds.

Alcohols↗
PubMed2003

Extraction and formation dynamic of oak-related volatile compounds from different volume barrels to wine and their behavior during bottle storage.

The extraction rate of furfuryl aldehydes, guaiacol, and 4-methylguaiacol, cis- and trans-oak lactone, and vanillin and the formation rate of furfuryl alcohol and the volatile phenols 4-ethylguaiacol and 4-ethylphenol have been studied in wines matured in different capacity oak barrels (220, 500, and 1000 L). Also, the behavior of these compounds during 1 year of wine bottle storage was followed. The lactones were extracted at a linear rate with large differences that depended on barrel volume. Those compounds related to oak toasting (guaiacol, 4-methylguaiacol, furfuryl aldehydes, and vanillin) seemed to be extracted faster during the first days of oak maturation except for vanillin, which required at least 3 months to accumulate in the wine. The volatile phenols, 4-ethylphenol and 4-ethylguaiacol, were formed in large quantities after the first 90 days of oak maturation, coinciding with the end of spring and beginning of summer. Wines matured in 1000-L oak barrels resulted in the lowest levels of volatile compound accumulation. During bottle storage, some compounds decreased in their concentration (5-methylfurfural, vanillin), others experienced increases in their levels (lactones, furfural, 4-ethylguaiacol, 4-ethylphenol), and the concentration of other compounds hardly changed (guaiacol, furfuryl alcohol).

Benzaldehydes↗
PubMed2004

Effect of antioxidant protection of must on volatile compounds and aroma shelf life of Falanghina (Vitis vinifera L.) wine.

Two vinification methods involving different degrees of antioxidant protection of Falanghina must during prefermentative steps, and referred as HAMP (high antioxidant must protection) and LAMP (low antioxidant must protection), were compared in terms of fermentation performances of four different yeast strains, composition of the volatile fraction of wines at the end of alcoholic fermentation, and shelf life of wines during storage. The use of HAMP technology resulted in wines with lower volatile acidity and higher concentrations of medium-chain fatty acid ethyl esters, acetates, and volatile fatty acids. For two of the four strains a lower concentration of isoamyl alcohol was also observed. HAMP wines also revealed increased shelf life because of the higher concentration of odor active esters at the end of storage and better preservation of varietal aromas.

Antioxidants↗
PubMed2004

Changes in physicochemical characteristics and volatile constituents of strawberry (Cv. Cigaline) during maturation.

Changes in the volatile composition of strawberries (cv. Cigaline) at six stages of maturity, from 28 to 44 days after anthesis, were investigated over two harvesting seasons. Volatiles were isolated by direct solvent extraction and analyzed by means of GC-FID and GC-MS, with special attention to the quantification of furanones. Firmness, skin color, soluble solids (SS), titratable acidity (TA), SS/TA ratio, organic acids, and sugars were also determined. With increasing maturity, soluble solids, SS/TA ratio, Minolta a value, and levels of sucrose, glucose, fructose, and malic acid increased, whereas Minolta L value, hue angle (), titratable acidity, and levels of citric acid decreased. Furanones and esters were generally not detected before half-red fruits, whereas C(6) compounds were the main compounds in immature fruits. During maturation, levels of these so-called green components decreased drastically, whereas levels of key flavor compounds increased significantly and were closely correlated with skin color development. Maximum volatile production was observed in fully red fruits.

Chemical Phenomena↗
PubMed2004

Analysis of the volatile aroma constituents of parental and hybrid clones of pepino (Solanum muricatum).

The volatile constituents of 10 clones (4 parents with different flavors and 6 hybrids from selected crossings among these parents) of pepino fruit (Solanum muricatum) were isolated by simultaneous distillation-extraction and analyzed by gas chromatography-mass spectrometry (GC-MS). Odor-contributing volatiles (OCVs) were detected by GC-olfactometry-MS analyses and included 24 esters (acetates, 3-methylbutanoates, and 3-methylbut-2-enoates), 7 aldehydes (especially hexenals and nonenals), 6 ketones, 9 alcohols, 3 lactones, 2 terpenes, beta-damascenone, and mesifurane. Among these compounds, 17, of which 5 had not been reported previously in pepino, were found to contribute significantly to pepino aroma. OCVs can be assigned to three groups according to their odor quality: fruity fresh (acetates and prenol), green vegetable (C6 and C9 aldehydes), and exotic (lactones, mesifuran, and beta-damascenone). Quantitative and qualitative differences between clones for these compounds are clearly related to differences in their overall flavor impression. The positive value found for the hybrid-midparent regression coefficient for volatile composition indicates that an important fraction of the variation observed is inheritable, which has important implications in breeding for improving aroma. Significant and positive correlations were found between OCVs having common precursors or related pathways.

Fruit↗
PubMed2005

Volatile components from mango (Mangifera indica L.) cultivars.

The volatile components of 20 mango cultivars were investigated by means of simultaneous distillation-extraction, GC, and GC-MS. Three hundred and seventy-two compounds were identified, of which 180 were found for the first time in mango fruit. The total concentration of volatiles was approximately 18-123 mg/kg of fresh fruit. Terpene hydrocarbons were the major volatiles of all cultivars, the dominant terpenes being delta-3-carene (cvs. Haden, Manga amarilla, Macho, Manga blanca, San Diego, Manzano, Smith, Florida, Keitt, and Kent), limonene (cvs. Delicioso, Super Haden, Ordonez, Filipino, and La Paz), both terpenes (cv. Delicia), terpinolene (cvs. Obispo, Corazon, and Huevo de toro), and alpha-phellandrene (cv. Minin). Other qualitative and quantitative differences among the cultivars could be demonstrated.

Chromatography, Gas↗