Benzene Acetaldehyde Research Articles

Determination of volatile compounds in turbot (Psetta maxima) during refrigerated storage by headspace solid-phase microextraction and gas chromatography-mass spectrometry.

A procedure based on headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS)was developed for the study of the volatile profile characteristics of turbot during refrigerated storage at 4°C for 20 days in order to find possible markers of freshness or spoilage. A total of 61 volatile compounds including aldehydes, ketones, esters, alcohols, alkenes, alkanes, aromatics, amines and others were identified in turbot muscle extracted by the optimised HS-SPME method. The volatile profile characteristics of turbot at different storage periods were specified by principal component analysis (PCA). The concentrations of hexanal, heptanal, (2E,4E)-heptadienal, acetophenone, 2-undecanone and 1-octen-3-ol decreased during storage, whereas benzene acetaldehyde, 6-methyl-5-hepten-2-one, 2-nonanone, acetic acid butyl ester, 3-methyl-1-butanol and trimethylamine increased. SPME-GC-MS combined with PCA may be a useful method for monitoring the volatile profile characteristics of turbot during storage, which could be potentially used for freshness evaluation.

Comparative analysis of volatile constituents in Bacillus thuringiensis (Bt) cotton (RCH 2 Bt) and non-Bt cotton by gas chromatography-mass spectrometry

The differences in composition and concentrations of volatile allelochemicals between transgenic Bacillus thuringiensis (Bt) cotton and non Bt cotton leaves were compared and analyzed by using gas chromatography-mass spectrometry (GC-MS). The dominant compounds present in both non Bt and Bt cotton leaves were α-caryophyllene (4.62, 1.42), β-myrcene (3.67, 3.68), β-carene (0.31, 0.80), benzene acetaldehyde (0.88, 0.48), heptanoic acid (2.0, 0.67), 1-methoxy, 2-methyl benzene (0.67, 0.30) and acetic acid, phenyl methyl ester (4.32, 2.48). The differences in main components and ratios of volatile allelochemics between Bt cotton and non Bt cotton suggested that, the expression of Bt toxin protein in cotton was found to have an impact on their volatile profiles.

Methyl chavicol reactions with ozone, OH and NO3 radicals: Rate constants and gas-phase products

The rate constants for methyl chavicol reactions with OH and NO3 radicals and O3 have been measured using the relative rate method at (298 ± 1) K and atmospheric pressure. The constants are kmethylchavicol+OH=(5.20±0.78)×10−11cm3molecule−1s−1, kmethylchavicol+NO3=(3.58±0.67)×10−14cm3molecule−1s−1 and kmethylchavicol+O3=(1.03±0.23)×10−17cm3molecule−1s−1. To more clearly understand the main atmospheric degradation mechanism of methyl chavicol, the products of the methyl chavicol + OH reaction were also investigated by thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). The identified products were 4-methoxytoluene, 4-methoxybenzaldehyde, 4-methoxy benzene acetaldehyde and 4-methoxybenzeneacetic acid. A possible formation mechanism for the main products is also proposed. The results indicate that methyl chavicol could have an impact on atmospheric chemistry at the regional scale and could also contribute to the production of secondary organic aerosol.

Chemical Composition of the Essential Oil of Fresh Wild <i>Syringa pubescens</i> Flowers from China

The essential oil of fresh wild Syringa pubescens flowers from China was obtained by hydrodistillation and identified by GC–MS. Altogether 49 components, mostly terpenoids and benzene derivatives, were identified. Many compounds are responsible for flowery or flowery-like aroma, such as benzyl alcohol, benzene acetaldehyde, cis-linalool oxide (furan), linalool, phenylethyl alcohol, α-terpineol, myrtenol, cis-geraniol, p-vinylguaiacol, eugenol, trans-nerolidol, etc. The predominant volatile compound in fresh wild Syringa pubescens flowers was furfural, followed by phenylethyl alcohol, carveol, borneol, eugenol, linalool, 2-propenylbenzoate, camphor, 4-terpineol, α-terpineol, benzaldehyde, trans-nerolidol, α-cadinol, thujone and benzyl alcohol. These results suggest that essential oil of fresh wild Syringa pubescens flowers has important flowery or flowery-like aroma properties and may be useful as a natural flavor to replace synthetic flavor.

Production of monoterpenoids and aroma compounds from cell suspension cultures of Camellia sinensis

Cell suspension cultures of Camellia sinensis were established in 250 ml shake flasks. Flasks contained 50 ml liquid medium of either Murashige and Skoog (MS), N/5 MS or Heller medium containing different levels of 6-benzyladenine (BA) (0.05–2 mg l−1), 2,4-dichlorophenoxyacetic acid (2,4-D) (1–10 mg l−1), and sucrose (10–50 g l−1). Moreover, the pH of the medium was varied from 5.2–6.2. In addition, cultures were subjected to light irradiation as well as to complete darkness. Following optimization of aroma and terpenoid extraction methods, cell cultures were analyzed for the volatile compounds using GC/MS. A total of 43 compounds were identified using the micro SDE apparatus. Among the major monoterpenoids obtained were α-terpineol and nerol. Moreover, other high aroma-value compounds, including 2-ethyl hexanol, benzyl alcohol, benzene acetaldehyde, nonanal and phenylethylalcohol were also detected. The highest levels of these compounds were obtained from cell suspension cultures grown in MS medium containing 5 mg l−1 2,4-D, 1 mg l−1 BA and 30 g l−1 sucrose at pH of 5.8 with incubation in complete darkness.

Comparison of aroma compounds in naturally fermented and inoculated Chinese soybean pastes by GC-MS and GC-Olfactometry analysis

The industrial fermentation of Chinese soybean pastes has the advantages of high production efficiency and quality consistency. However, the aroma of the current industrial products (with inoculation) is often less satisfactory than the naturally fermented products. In this study, the volatile compounds of natural fermented and inoculated Chinese soybean pastes were evaluated and compared. Results showed that the natural fermented samples had higher contents of volatiles than the inoculated samples, and seven volatile compounds were identified as aroma active compounds for natural fermented sample including 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone, ethyl linoleate, 2,3-butanediol, acetic acid, fufural, benzene acetaldehyde and pyrazine 2,6-dimethyl. The inoculated sample had lower sensations of soy sauce, grease, yeast culture and osmanthus, and higher sensations of burning, sourness and cooked rice than the natural fermented samples. Further research is needed to elucidate the effects of raw materials, microbial community and processing conditions on the generation of aromas of fermented Chinese soybean pastes.

GC/MS Analysis of Citrus aurantium L. Hydrolate and its Comparison with the Commercial Samples GC/MS Analysis of Citrus aurantium L. Hydrolate and its Comparison with the Commercial Samples

The chemical composition of the Hydrolate of Citrus aurantium L. (Rutaceae) flowers (neroli) grown in Iran, and two commercial hydrolates were analyzed by GC/MS. Thirty compounds (90.3%) were identified in the Hydrolate by the use of laboratory apparatus, thirty-eight compounds (83.4%) in the Hydrolate from the traditional method and fifteen compounds (98.3%) in the industrially produced sample. The major compounds within the Hydrolate obtained in the laboratory were geraniol (26.6%), a-terpineol (20.7%), linalool (15.4%) and benzene acetaldehyde (5.5%). Linalool (44.1%), methyl anthranilate (11.8%) and cis-linalool oxide (6.1%) were found in high percentages in the Hydrolate from the obtained traditional sample. 1,8-Cineol (15.9%), linalool (13.8%) and a-terpineol (6.6%) were more than other constituents in the industrially obtained hydrolate.

Chemical composition and antibacterial activity of essential oils of Tripleurospermum disciforme in three developmental stages

Context: Tripleurospermum disciforme (C.A. Mey) Schultz Bip. (Asteraceae) is a widespread biennial species which also has traditional medicinal uses. According to the few recent studies, essential oils of this species exhibit anti-inflammatory, antispasmodic, antiseptic, antifungal, antiulcer, and antioxidant activity.Objective: The chemical compositions of the hydrodistilled oils of T. disciforme of Iranian origin are studied in the stages of prior to flowering, flowering, and post flowering, for the first time. Also, we investigated the antibacterial activities of the oils.Materials and methods: The essential oils of air-dried T. disciforme were obtained by hydrodistillation in three different developmental stages and analyzed by gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the isolated essential oil, in the three stages, was also investigated against four Gram-positive and four Gram-negative bacteria.Results: Twenty-one components were identified in the essential oils of T. disciforme, and the highest amount of oil was extracted at the flowering stage. The main component of the species in the flowering stage was β-farnesene (22.46%) and the other major components were β-sesquiphellandrene (17.85%), p-methoxy-β-cyclopropylstyrene (16.64%), heptadecane (10.6%), p-methoxy-humulene oxide (6.88%) and benzene acetaldehyde (9.3%). The MIC of essential oil was evaluated from 4 µL ml−1 against Staphylococcus subtilis and Bacillus cereus to 22 µL ml−1 against Citrobacter amalonaticus.Discussion and conclusion: This study demonstrates the occurrence of β-farnesene/β-sesquiphellandrene chemotype of T. disciforme in western regions of Iran that are different from previous reports. The findings also showed that the essential oils T. disciforme have excellent antibacterial activities and thus have great potentiality to be used as a resource for natural health products.

Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

Abstract. We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1 h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

Genetic Diversity of Volatile Components in Xinjiang Wild Apple ( Malus sieversii)

To evaluate genetic relationships using qualitative and/or quantitative differentiation of volatile components in Xinjiang Wild Apple ( Malus sieversii (Lebed.) Roem.) and to acquire basic data for the conservation and utilization of the species, aroma components in ripe fruit of M. sieversii obtained from 30 seedlings at Mohe, Gongliu County, Xinjiang Autonomic Region, China, and in ripe fruit of 4 M. pumila cultivars (‘Ralls’, ‘Delicious’, ‘Golden Delicious’, and ‘Fuji’) were analyzed using head space-solid phase microextraction and gas chromatography-mass spectrometry. The results indicated that the values of similarity coefficient concerning volatile types between the two species were in accordance with the evolution of M. pumila cultivars (forms), and that M. sieversii seedlings showed considerable genetic variations in these aspects: the total content of volatile components, the classes and contents of each compound classes, the segregation ratio, and content of main components. The results showed significant difference among seedlings and wide genetic diversity within the populations. Comparison of the volatile components in M. sieversii with those in M. pumila cultivars showed that the common compounds whose number were larger than five with the contents over 0.04 mg/L simultaneously between M. sieversii and M. pumila cultivars belonged to esters, alcohols, aldehydes or ketones. This suggests fundamental identity in main volatile components of M. sieversii and M. pumila cultivars. The results above sustained the conclusion “ M. sieversii is probably the ancestor of M. pumila”. However, there were 48 compounds present in M. pumila that were not detected in M. sieversii, including 6 character impact components (i.e., propyl acetate, (Z)-3-hexenal, 2-methyl-1-butanol acetate, pentyl acetate, 3-furanmethanol, and benzene acetaldehyde). This suggested that in the domestication of M. pumila, introgression of other apple species, except for M. sieversii, by interspecies hybridization was possible. There were 177 compounds in total belonging to 11 classes detected in 30 M. sieversii seedlings, including esters, alcohols, ketones, aldehydes, acids, benzene ramifications, terpenes, heterocycles, hydrocarbon derivates, acetals, and lactones. Among them, acetals and lactones were not detected in M. pumila cultivars, 90 compounds were unique to M. sieversii, and 7 components (1-butanol, ethyl butanoate, 1-hexanol, ethyl hexanoate, 3-octen-1-ol, ethyl octanoate, and damascenone) belonged to character impact odors. Thus, the potential of M. sieversii in “utilization conservation” is enormous as a rare germplasm on genetic improvement of M. pumila cultivars.

Analysis of volatile compounds emitted from fresh Syringa oblata flowers in different florescence by headspace solid-phase microextraction–gas chromatography–mass spectrometry

In this study, a simple and solvent-free method was developed for determination of the volatile compounds from fresh flowers of Syringa oblata using headspace solid-phase microextraction and gas chromatography–mass spectrometry. The SPME parameters were studied, the optimum conditions of a 65 μm polydimethylsiloxan/divinylbenezene (PDMS/DVB), extraction temperature of 25 °C and extraction time of 30 min were obtained and applied to extraction of the volatile compounds emitted from fresh flowers of S. oblata. The volatile compounds released from fresh flowers of S. oblata were separated and identified by GC–MS. Lilac aldehyde A, lilac aldehyde B, lilac aldehyde C, lilac aldehyde D, lilac alcohol A, lilac alcohol B, lilac alcohol C, lilac alcohol D, α-pinene, sabinene, β-pinene, myrcene, d-limonene, eucalyptol, cis-ocimene, benzaldehyde, terpinolene, linalool, benzene acetaldehyde, α-terpineol, p-methoxyanisole, p-anisaldehyde, ( Z, E)-α-farnesene and ( E, E)-α-farnesene were the most abundant volatiles released from fresh flowers of S. oblata var. alba. The relative contents of main volatile fragrance were found to be different in emissions from two varieties of S. oblata flowers (white or purple in color). The four isomers of lilac alcohol and four isomer lilac aldehyde were the characteristic components of the scent of fresh flowers of S. oblata. The main volatile fragrance from fresh flowers of S. oblata var. alba in different florescence ((A) flower buds; (B) at the early stage of flower blooming; (C) during the flower blooming; (D) at the end of flower blooming; (E) senescence) were studied in this paper. The results demonstrated that headspace SPME–GC–MS is a simple, rapid and solvent-free method suitable for analysis of volatile compounds emitted from fresh flowers of S. oblata in different florescence.

Chemometric evaluation of concentration profiles from compounds relevant in beer ageing

In 43 beer samples from 14 breweries the concentrations of 16 compounds have been determined in fresh samples as well as in artificially aged samples. The substances measured comprise aldehydes, ketones and esters; some of them are indicators for the change of flavor and taste during ageing. Significantly increased concentrations in aged samples were found for benzene acetaldehyde, nicotinic acid ethylester, furfural, and 5-hydroxymethyl-2-furancarboxaldehyde. Principal component analysis showed a separation of the fresh and aged samples. Some of the fresh samples of lower quality were located in the area typically covered by aged samples.

Volatile components from Anthriscus sylvestris (L.) Hoffm.

The volatile components of fresh leaves and roots from Anthriscus sylvestris (L.) Hoffm., obtained through hydrodistillation, were analysed by GC and GC–MS. This was compared to dichloromethane extracts of both fresh and dried leaf and root material. The monoterpene fraction (69–70%) dominated, while β-phellandrene (39–45%) was the main component in both the leaf and the root oil. Other components in the leaf oil were β-myrcene (17%), sabinene (6.2%), Z-β-ocimene (5.4%) and benzene acetaldehyde (4.1%). In the roots we found Z-β-ocimene (16.9%) and α-pinene (4.6%) as other major components. These principle constituents of both essential oils were also present in the dichloromethane extracts of the fresh and dried leaves and the roots, although in much smaller percentages. Comparing hydrodistillation of fresh plant material with a dichloromethane extract, the latter yielded a considerably lower amount of constituents. In addition, air drying and freeze drying resulted in a significant loss of volatile constituents as compared to fresh material (dichloromethane extract).

Phytotoxic and fungitoxic activities of the essential oil of kenaf (Hibiscus cannabinus L.) leaves and its composition.

The chemical composition of the essential oil of kenaf (Hibiscus cannabinus) was examined by GC-MS. Fifty-eight components were characterized from H. cannabinus with (E)-phytol (28.16%), (Z)-phytol (8.02%), n-nonanal (5.70%), benzene acetaldehyde (4.39%), (E)-2-hexenal (3.10%), and 5-methylfurfural (3.00%) as the major constituents. The oil was phytotoxic to lettuce and bentgrass and had antifungal activity against Colletotrichum fragariae, Colletotrichum gloeosporioides, and Colletotrichum accutatum but exhibited little or no algicidal activity.

Analysis of Volatile Flavor Components in Roasted Peanuts Using Supercritical Fluid Extraction and Gas Chromatography−Mass Spectrometry

A method for extraction and identification of volatile flavor components in roasted peanuts is described. The method is based on supercritical fluid extraction (SFE), with identification using gas chromatography-mass spectroscopy (GC-MS) in scan mode. Appropriate choice of supercritical fluid density (0.35 g/mL of CO2) and extraction temperature (50 °C), at a pressure of 96 bar, results in selective extraction of compounds associated with roasted flavor rather than nonvolatile lipid material. The compounds examined in this study were hexanol, hexanal, methylpyrrole, benzene acetaldehyde, methylpyrazine, 2,6-dimethylpyrazine, ethylpyrazine, 2,3-dimethylpyrazine, 2,3,5trimethylpyrazine, 2-furancarboxaldehyde, 2-ethyl-5-methyl- and 2-ethyl-6-methylpyrazine, and 3-ethyl-2,5-dimethylpyrazine. Careful grinding of frozen samples and alternate layering with silanized glass wool in the extraction thimble allows good recovery of the volatiles (>85%) in a single extraction step. Comparison of chromatograms for samples produced over a range of roasting conditions and sensory panel results shows that this method can be used to relate roasting conditions and consumer acceptance of roast quality.

Tastes and volatiles of tropical-type sweet potatoes

For fresh market sweet potato [Ipomea batatas (L.) Lam] quality is defined in terms of attractiveness, sweetness, texture, and flavor composed of taste and odor after cooking. There is a scarcity of information regarding taste and volátiles of tropical type sweet potatoes. The first objective of this research was to provide a robust set of data for carbohydrate type and levels, alcohol insoluble solids (AIS) and volatile organic compounds (VOC) from six cultivars of sweet potato, data which will allow us to have a quantitative selection tool besides crop yield, tuber size and appearance. The second objective was to relate VOC differences among sweet potato cultivars that can be attributed to chemical and physical differences of the pulp before and after cooking. A three- harvest study was conducted to identify and determine major carbohydrate content, AIS, starch granule diameter and form, and tastes and odors of six cultivars of sweet potato, which were very sweet ('Gem'), sweet ('Miguela' and Travis'), moderately sweet ('Viola' and 'Martina') and non-sweet ('Ninety- nine'). The average AIS contents were 81, 77, 79, 85, 66, and 76% for 'Martina', 'Miguela', 'Ninety-nine', 'Viola', 'Gem' and 'Travis', respectively. Scanning electron micrograph (SEM) indicated that the average starch granule diameters were 12.9, 15.3, 16.9 and 25.2 |jm for 'Martina', 'Miguela', 'Ninety-nine' and 'Viola', respectively. In addition, all of the sweet potato starch granules had both spherical and polygonal granules. The cultivars with greatest change in AIS and maltose content (raw vs. baked) were 'Gem', the sweetest, and 'Travis'. Correlation between sucrose index (SI) and AIS for baked samples was 0.956; for AIS and sweetness, correlation was -0.823. A similar correlation between the AIS and maltose was obtained for the data from the three harvests (-0.8493). Fifty volatile organic compounds of baked sweet potatoes were trapped in cold methylene chloride. The predominant volátiles were hexanal, 3-pente-2-ol, and isoledene. Other sweet aromas detected were 2,4-decadienal, 2-pentyl furan, benzaldehyde, 4-methyl-4-hydroxy-2-pentanone, and benzene acetaldehyde. The great differences in relative concentrations of volátiles among cultivars seem to be related to the synthesis of maltose and the content of AIS.

Tastes and volatiles of tropical-type sweet potatoes.

For fresh market sweet potato [Ipomea batatas (L.) Lam] quality is defined in terms of attractiveness, sweetness, texture, and flavor composed of taste and odor after cooking. There is a scarcity of information regarding taste and volátiles of tropical type sweet potatoes. The first objective of this research was to provide a robust set of data for carbohydrate type and levels, alcohol insoluble solids (AIS) and volatile organic compounds (VOC) from six cultivars of sweet potato, data which will allow us to have a quantitative selection tool besides crop yield, tuber size and appearance. The second objective was to relate VOC differences among sweet potato cultivars that can be attributed to chemical and physical differences of the pulp before and after cooking. A three- harvest study was conducted to identify and determine major carbohydrate content, AIS, starch granule diameter and form, and tastes and odors of six cultivars of sweet potato, which were very sweet ('Gem'), sweet ('Miguela' and Travis'), moderately sweet ('Viola' and 'Martina') and non-sweet ('Ninety- nine'). The average AIS contents were 81, 77, 79, 85, 66, and 76% for 'Martina', 'Miguela', 'Ninety-nine', 'Viola', 'Gem' and 'Travis', respectively. Scanning electron micrograph (SEM) indicated that the average starch granule diameters were 12.9, 15.3, 16.9 and 25.2 |jm for 'Martina', 'Miguela', 'Ninety-nine' and 'Viola', respectively. In addition, all of the sweet potato starch granules had both spherical and polygonal granules. The cultivars with greatest change in AIS and maltose content (raw vs. baked) were 'Gem', the sweetest, and 'Travis'. Correlation between sucrose index (SI) and AIS for baked samples was 0.956; for AIS and sweetness, correlation was -0.823. A similar correlation between the AIS and maltose was obtained for the data from the three harvests (-0.8493). Fifty volatile organic compounds of baked sweet potatoes were trapped in cold methylene chloride. The predominant volátiles were hexanal, 3-pente-2-ol, and isoledene. Other sweet aromas detected were 2,4-decadienal, 2-pentyl furan, benzaldehyde, 4-methyl-4-hydroxy-2-pentanone, and benzene acetaldehyde. The great differences in relative concentrations of volátiles among cultivars seem to be related to the synthesis of maltose and the content of AIS.