Chemical Composition Of Volatile Fraction Research Articles

Improving the quality of liquid smoke by filtration using membranes

Liquid smoke (LS) is getting more attention in many applications, especially food preservation. However, there is still a big problem with the purity of LS. The objective of this study is to improve the quality of LS using membrane filtration. The filtrations were conducted using ultrafiltration or nanofiltration membrane at various pressures. The quality of LS before and after filtration was compared based on their appearance. During the filtration process, LS changed from a dark yellow fluid with a pungent odor to a pale colorless substance with a less smokey odor and a slightly sweet aroma. The color and fragrance parameters of LS before and after filtration using UF membranes were not significantly different. NF membrane filtering had the opposite effect on the appearance of LS. Chemical composition of volatile fraction was studied by GC/MS. Phenols were the predominant aromatic chemicals found in all samples, with LS containing up to 80.8%, 17.53% in treated LS by UF membrane (2 bars), and 48.31% in NF membrane (5 bars). The results proved that the membrane processing can eliminates potentially toxic compounds while still imparting the desired flavors and pleasent aromas of LS.

Chemical Composition of Volatiles of Eight Geranium L. Species from Vlasina Plateau (South Eastern Serbia).

Geranium species are widely used in traditional medicine of Balkan. The aim of this work was to investigate and compare chemical composition of volatile fractions obtained by hydrodistillation from aerial parts of G. macrorrhizum, G. phaeum, G. sanguineum, G. robertianum, G. palustre, G. pyrenaicum, G. columbinum and G. lucidum as well as from underground parts of G. macrorrhizum and G. phaeum, originated from Vlasina plateau in South Eastern Serbia. The volatiles were analyzed using GC/MS and GC-FID. G. palustre volatiles have been studied for the first time with β-selinene (18.6 %) as a characteristic compound. The cluster analysis revealed separation of volatiles into two main groups. Volatile fractions of G. macrorrhizum were separated from all other samples due to high sesquiterpene content (92.3 % in aerial and 94.6 % in underground parts). The volatile fractions of other samples were mainly composed of sesquiterpenes (10.8-61.8 %), diterpenes (12.9-43.0 %) and fatty acids and their derivatives (6.6-21.6 %) with the exception of volatile fraction of G. phaeum underground parts which was dominated only by fatty acids and their derivatives (76.6 %). The results presented in this article contribute to the knowledge on the chemistry of this genus and advances the knowledge on flora of southeast Serbia.

Chemical composition, antimicrobial and insecticidal activities of the tunisian Citrus aurantium essential oils

The chemical composition of volatile fractions from leaves, flowers and peels of Citrus aurantium growing in Tunisia obtained by hydrodistillation were analysed using GC and GC-MS. Furthermore, the isolated essential oils were evaluated for their in vitro antimicrobial activity against eight bacteria, eight phytopathogenic and nine human pathogenic fungi. The essential oils from peels and its main compound limonene have been found to possess strong contact toxicity against four storage-grain insects. The highest mortality rate was observed when the essential oil was applied against Cryptolestes ferrugineus, Liposcelis bostrychophila and Tribolium castaneum.

Fast pyrolysis of trunk wood and stump wood from a Brazilian eucalyptus clone

The objective of this study was to compare yields and chemical composition of volatile fraction of bio-oil produced from fast pyrolysis of trunk wood and stump wood of Eucalyptus urograndis. Ground material was processed in a fluidized bed pilot plant equipped with a continuous reactor at temperatures of 500–600 °C. Light bio-oil fraction from each material was collected and vacuum distilled. The oily volatile fraction was characterized by GC/MS. Yield of charcoal was higher for stump wood than for trunk wood and the opposite behavior was observed for the yield of light and heavy bio-oil fractions and of gases. Yields of volatile compounds were statistically equal for trunk and stump wood, both representing about 6% of the initial dry biomass. The results demonstrate the technical viability of having stump wood as a source of volatile oils with chemical composition similar to commercial liquid smoke products.

Relationships between volatile compounds and sensory characteristics in virgin olive oil by analytical and chemometric approaches

The volatile fraction of virgin olive oil is characterised by low molecular weight compounds that vaporise at room temperature. In order to obtain an aroma profile similar to natural olfactory perception, the composition of the volatile compounds was determined by applying dynamic headspace gas chromatography, performed at room temperature, with a cryogenic trap directly connected to a gas chromatograph-mass spectrometer system. Samples were also evaluated according to European Union and International Olive Council official methods for sensory evaluation. In this paper, the composition of the volatile fraction of 25 extra virgin olive oils from different regions of Italy was analysed and some preliminary considerations on relationships between chemical composition of volatile fraction and sensory characteristics are reported. Forty-two compounds were identified by means of the particular analytical technique used. All the analysed samples, classified as extra virgin by the panel test, never present peaks whose magnitude is important enough in defected oils. The study was focused on the evaluation of volatile compounds responsible for the positive impact on olive odour properties ('green-fruity' and 'sweet') and olfactory perception. Chemometric evaluation of data, obtained through headspace analysis and the panel test evaluation, showed a correlation between chemical compounds and sensory properties. On the basis of the results, the positive attributes of virgin olive oil are divided into two separated groups: sweet types or green types. Sixteen volatile compounds with known positive impact on odour properties were extracted and identified. In particular, eight compounds seem correlated with sweet properties whereas the green sensation appears to be correlated with eight other different substances. The content of the compounds at six carbon atoms proves to be very important in defining positive attributes of extra virgin olive oils and sensory evaluation.

Seasonal Evaluation and Chemical Composition of Volatile Fractions from Piper claussenianum by Hydrodistillation and SPME

The essential oils from Piper species are chemically diverse, with several biological activities as well as commercial and pharmacological values reported. This work aims to compare the volatile constituents from leaves and inflorescences obtained by two different extraction techniques and show the seasonal variation of nerolidol in the essential oil from leaves of Piper claussenianum. The P. claussenianum volatile components were obtained by headspace solid-phase microextraction (HS-SPME) and hydrodistillation, coupled to gas chromatography/mass spectrometry (GC/MS) analysis. Leaf and inflorescence volatile fractions were analyzed in fresh and dried conditions. In total, 40 compounds were identified, accounting for 88.8–97.7% of the constituents. The high percentage of nerolidol in the leaves and linalool in the inflorescences were remarkable in this species, accounting for up to 77.0% and up to 50.0%, respectively, collected monthly. Results of (E)-nerolidol seasonal variation study carried out in the growth period of January/December 2009, suggest the plant leaves which provide an essential oil with high content of (E)-nerolidol over 88.0% are primarily observed in the September/December collection period.

Qualitative and quantitative analysis of volatile components of Teucrium massiliense L. – identification of 6‐methyl‐3‐heptyl acetate as a new natural product

AbstractVolatile components extracted from the aerial parts and separated organs of Corsican and Sardinian Teucrium massiliense have been studied. The chemical composition of essential oils obtained by hydrodistillation (HD) has been investigated using GC–RI, GC–MS (EI and CI modes) and 13CNMR spectroscopy. For the first time, a real concentration via calibration curves and response factor calculations has been determined for each oil component. The concentrations of the major components were 6‐methyl‐3‐heptyl acetate (23.83–18.16 g/100 g), 3‐octyl acetate (10.55–6.95 g/100 g), isobutyl isovalerate (7.67–2.91 g/100 g), germacrene D (6.13–1.01 g/100 g) and linalool (6.63–5.23 g/100 g). To the best of our knowledge, the occurrence of 6‐methyl‐3‐heptyl acetate as a natural product is reported for the first time. Furthermore, the chemical composition of volatile fractions emitted from the aerial parts and separated organs of T. massiliense L. has been studied by HS–SPME/GC–RI and GC–MS after optimization of SPME parameters. Concerning the contribution of plant organs to the aromatic plant fingerprint, we noted that the flowers produced more volatiles than other organs. The volatile fractions obtained from the different organs were qualitatively quite similar to each other but differed in the percentages of their major components. Also, the influence of HS–SPME extraction parameters (equilibrium and extraction times and temperature) on the chemical composition of the plant volatile fraction is discussed. Copyright © 2010 John Wiley & Sons, Ltd.

Chemical Composition of Volatile Fraction of Fresh and Dry Artemisia capillaris Thunb. from Kumaon Himalaya

In order to investigate the influence of drying, the essential oil from fresh, shade dried and sun dried flowering twigs of Artemisia capillaris was compared. The essential oil content was found higher in fresh herb (0.63 %) compared to dry materials (0.57 %). GC and GC-MS analysis enabled identification of twenty five components, representing 93.8 % - 95.0 % of the total oil. The major components of these oils were capillene (32.5 % - 39.6 %), γ-terpinene (26.4 % -34.3 %), eugenol (7.4 % - 10.1 %), β-caryophyllene (4.8 % - 7.9 %) and ρ-cymene (2.0 % - 5.1 %). Interestingly, capillene content was found to decrease, whereas γ-terpinene and eugenol increased on drying. The study suggested that the A. capillaris biomass should be distilled afresh for better oil yield and quality under hill conditions of Kumaon Himalaya.

Volatile and molecular characterization of two Portuguese endemic species: Angelica lignescens and Melanoselinum decipiens

Chemical and genetic differences of 11 individuals of Angelica lignescens and 3 individuals of Melanoselinum decipiens were studied to determine whether volatile components could be used as taxonomical markers and to examine the correlation between molecular and chemical markers. The volatiles were isolated from each individual by distillation–extraction and analyzed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The same plants were analyzed by Inter Simple Sequence Repeat (ISSR) using 14 arbitrary primers. The main component of volatile fraction isolated from vegetative aerial parts of A. lignescens was limonene (57–86%) while in M. decipiens the main components detected were β-pinene (38–47%) and sabinene (1–33%). Cluster analyses based both on the chemical composition of volatile fraction and on molecular markers grouped the 14 accessions in two main groups, corresponding to each of the two species under study. Considering the species together, a moderate Pearson's correlation of r = 0.61 was obtained between the two analyses.

Comparison of liquid–liquid extraction with headspace methods for the characterization of volatile fractions of commercial hydrolats from typically Mediterranean species

Chemical composition of volatile fractions of nine commercial hydrolats and corresponding essential oils obtained using an industrial process were studied. The hydrolat volatile fractions were reported for the first time. A comparative study of those obtained, on the one hand, by liquid–liquid extraction (LLE) and, on the other hand, using five solid-phase microextraction (SPME) fibers and also purge-and-trap-automatic thermal desorption (P&T-ATD) was conducted with analysis performed by GC and GC/MS. The use of various techniques has resulted in a change of chromatographic profile of the hydrolat volatile fractions. Quantitative differences were established between chemical compositions of headspace and those obtained by a conventional method (LLE). Statistical analyses were carried out to summarize the results.

Constituintes voláteis de própolis piauiense

The essential oils of five samples obtained in different regions of the state of Piaui were analyzed by GC-MS. Ninety-one volatile constituents were tentatively identified and eight were positively identified. The principal components obtained from each sample were: 1,8-cineole, exo-fenchol, terpin-4-ol and fenchone (Teresina), a-pinene, caryophyllene oxide, b-pinene and a-copaene (Pio IX), (E)-caryophyllene, a-copaene, a-pinene, caryophyllene oxide and d-cadinene (Campo Maior), (E)-caryophyllene, a-gurjunene and b-selinene (Pedro II) and (E)-caryophyllene, a-gurjunene, d-cadinene and a-copaene (Lagoa de Sao Francisco). The five samples presented differences in the chemical composition of volatile fractions. The studies pointed out the need of characterizing propolis from Piaui by geographic regions and by seasons (drought and rainy periods).

Analysis of volatile fraction, fixed oil and tegumental waxes of the seeds of two different cultivars of Helianthus annuus

The chemical composition of volatile fraction, fixed oil and tegumental waxes of the seeds of two Helianthus annuus L. cultivars (Carlos and Florom 350) were examined by GC and GC–MS. Many qualitative and/or quantitative differences were observed. α-Pinene, cis-verbenol and β-gurjunene were in both the main volatiles but with significant quantitative differences; moreover, Florom oil was characterized by a greater variety of constituents. The fixed oil and the waxes composition showed a general qualitative homogeneity, for both cultivars, even though marked quantitative differences were observable. The data obtained could be useful for the correct identification of the cultivars.