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1.
Ginger (Zingiber officinale Roscoe), a monocotyledonous, sterile cultigen, is widely used as a spice, flavoring agent, and herbal medicine. The pungency of fresh ginger is due to a series of homologous phenolic ketones of which [6]-gingerol is the major one. The gingerols are thermally unstable and can be converted to their corresponding shogaols, which are present in dried ginger. Fresh rhizomes of 17 clones of Australian ginger, including commercial cultivars and experimental tetraploid clones, were assayed by HPLC for gingerols and shogaols. [6]-Gingerol was identified as the major pungent phenolic compound in all samples, while [8]- and [10]-gingerol occurred in lower concentrations. One cultivar known as "Jamaican" contained the highest concentrations of all three gingerols and was the most pungent of the clones analyzed. Gingerols were stable in ethanolic solution over a 5-month period when stored at 4 degrees C. Shogaols were not identified in the extracts prepared from fresh rhizomes at ambient temperature, confirming that these compounds are not native constituents of fresh ginger. In contrast to previous findings, this study did not find significant differences in gingerol concentrations between the tetraploid clones and their parent diploid cultivar.  相似文献   

2.
Bioactivity of Backhousia citriodora: antibacterial and antifungal activity   总被引：2，自引：0，他引：2  
Backhousia citriodora products are used as bushfoods and flavorings and by the aromatherapy industry. The antimicrobial activity of 4 samples of B. citriodora oil, leaf paste, commercial tea (0.2 and 0.02 g/mL), and hydrosol (aqueous distillate) were tested against 13 bacteria and 8 fungi. Little or no activity was found to be associated with the leaf tea and hydrosol, respectively. Leaf paste displayed antimicrobial activity against 7 bacteria including Clostridium perfringens, Pseudomonas aeruginosa, and a hospital isolate of methicillin resistant Staphylococcus aureus (MRSA). The 4 essential oils were found to be effective antibacterial and antifungal agents; however, variation was apparent between oils that did not correlate with citral content. The antimicrobial activity of B. citriodoraessential oils was found to be greater than that of citral alone and often superior to Melaleuca alternifolia essential oil. B. citriodora has significant antimicrobial activity that has potential as an antiseptic or surface disinfectant or for inclusion in foods as a natural antimicrobial agent.  相似文献   

3.
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4.
The composition of the essential oil of Citrus tamurana Hort. ex Tanaka (Hyuganatsu), isolated by the cold-pressing method, was investigated by capillary GC and GC-MS. The effects of harvesting time, degree of freshness, and size of fruits on the composition of Hyuganatsu peel oils were also determined. A total of 126 volatile constituents were confirmed in the Hyuganatsu oils. The Hyuganatsu oils contained hydrocarbons (95.95-96.95%), aldehydes (0.33-0.62%), alcohols (1.91%-2.64%), ketones (0.40-0.62%), esters (0.28-0.39%), oxides (0.04-0.06%), acids (0.01%), and trace amounts of fugenol methyl ether. Monoterpene hydrocarbons were predominant. Limonene (80.35-82.39%), gamma-terpinene (7.71-9.03%), myrcene (2.11-2.28%), linalol (1.37-2.01%), and alpha-pinene (1.17-1.43%) were the most abundant components in Hyuganatsu oils. The principal sesquiterpene hydrocarbon was trans-beta-farnesene (0.60-1.04%), and its content in Hyuganatsu oils was higher than in oils of other citrus fruits. The number of ketones and the content of l-carvone in Hyuganatsu oils were higher than in other citrus oils.  相似文献   

5.
The essential oil yields obtained by hydrodistillation of the aerial parts of Hypericum androsaemum cultivated plants varied from 0.94 to 4.09 mg/g of biomass dry weight, depending of the harvest time. The respective analyses performed by gas chromatography and gas chromatography-mass spectrometry revealed more than 80 compounds, 72 of which were identified. Most of the compounds were sesquiterpene hydrocarbons, which, depending of the harvest time, corresponded to 43-78% of the total essential oil. The other compounds were distributed as monoterpene hydrocarbons, oxygen-containing sesquiterpenes, n-alkanes, 1-alkenes, and oxygen-containing monoterpenes, these being a minor group. In H. androsaemum in vitro shoots, sesquiterpene hydrocarbons represented >80% of the respective essential oil. Differences in the essential oil composition were found depending on the harvest time and origin, in vivo versus in vitro, of the plant material. The essential oil sampled in November was characterized by the highest levels of sesquiterpene hydrocarbons and a high number of n-alkanes and 1-alkenes, from C(18) to C(28), whereas that sampled in June of the following year showed the highest levels of n-nonane and 1-octene as well as monoterpene hydrocarbons, the second most representative group.  相似文献   

6.
The effect of fat content on the release of volatile aroma compounds from frankfurters has been investigated. Although the release of most n-alkanals, alcohols, ketones, and furans was little affected by changes in the fat content of frankfurters, that of monoterpene hydrocarbons, sesquiterpene hydrocarbons, terpenes containing oxygen, cyclopentenones, phenyl propanoids, and phenols was greatly increased when the fat content was decreased. Some odors were also detected more frequently in the low-fat than in the full-fat sausages. These included smoky odors, due to phenols, spicy, synthetic, and floral odors due to terpenes, and meaty, roasted odors caused by sulfur-containing heterocyclic compounds. The release of aroma compounds from frankfurters appears to be closely related to the solvation of these compounds in the lipid phase.  相似文献   

7.
蒸汽闪爆处理对生姜纤维吸附性能的影响   总被引：1，自引：1，他引：0  
生姜纤维来源于废弃的生姜渣,以生姜纤维资源化利用为前提,以制备一种高效处理染料废水的生物质吸附剂为目的,该文对生姜纤维进行蒸汽闪爆、冷冻粉碎联合处理得到闪爆粉碎生姜纤维吸附剂,探究了蒸汽闪爆处理及冷冻粉碎处理、不同吸附条件(吸附时间、pH值、盐浓度和蒸汽压强)对生姜纤维吸附性能的影响。结果表明:蒸汽压强为1.9 MPa时,闪爆粉碎生姜纤维对活性染料RB19的吸附量最高,其最大吸附量(115.12 mg/g)是原生姜纤维(48.80 mg/g)、粉碎生姜纤维(54.10 mg/g)的2.36倍、2.13倍,其吸附动力学过程符合准二阶动力学模型(R2为0.99),吸附等温线符合Langmuir模型(R2为0.99)。闪爆粉碎生姜纤维吸附能力经过吸附、解吸5次循环后仍保留80%,循环吸附性能良好。扫描电镜分析显示,随着蒸汽压强从1.3升高到1.9 MPa,生姜纤维内表面暴露出来,染料分子RB19更容易进入生姜纤维内部。X射线衍射(X-ray diffraction)分析显示,闪爆粉碎生姜纤维与生姜纤维相比,结晶指数从39%下降到20%,无定形区扩大,从而提高其吸附能力。研究结果可为生姜纤维用作染料废水吸附剂提供参考依据。  相似文献   

8.
Virgin olive oils were subjected to simulated common domestic processing, including frying, microwave heating, and boiling with water in a pressure cooker. The impact of these processes on polyphenol content and physicochemical characteristics of oils was assessed. Thermal oxidation of oils at 180 degrees C caused a significant decrease in hydroxytyrosol- and tyrosol-like substances. In contrast, oils heated for 25 h still retained a high proportion of the lignans 1-acetoxypinoresinol and pinoresinol. Thermal oxidation also resulted in a rapid degradation of alpha-tocopherol and the glyceridic fraction of oils. Microwave heating of oils for 10 min caused only minor losses in polyphenols, and the oil degradation was lower than that in thermoxidation assays. Again, lignans were the least affected polyphenols and did not change during microwave heating. Boiling a mixture of virgin olive oil and water in a pressure cooker for 30 min provoked the hydrolysis of the secoiridoid aglycons and the diffusion of the free phenolics hydroxytyrosol and tyrosol from the oil to the water phase. Losses of polyphenols were detected only at pH lower than 6. Moreover, alpha-tocopherol and the glyceridic fraction of oils were not modified during this process. It is worth noting that all the heating methods assayed resulted in more severe polyphenols losses and oil degradation for Arbequina than for Picual oil, which could be related to the lower content in polyunsaturated fatty acids of the latter olive cultivar. These findings may be relevant to the choice of cooking method and olive oil cultivar to increase the intake of olive polyphenols.  相似文献   

9.
More than 50 compounds were identified in essential oils from stems and leaves of Salvia officinalis L. plants harvested in July, in Arouca, in northern Portugal. About 40 of those compounds were also present in flower essential oils, collected from the same plants. alpha-Thujone was the major compound, representing about 55, 30, and 18% of the essential oils from stems, leaves, and flowers, respectively. Significant percentage variations in the main compound classes of the essential oils from shoots sampled over the year were recorded at two different sites in northern Portugal. From December to April, oxygenated monoterpenes (MO) decreased from approximately 67-72% to values of 42-43% of the essential oils. During the same time interval, the percentage of monoterpene hydrocarbons (MH) rose from 8-11% to 17-22%. At both sites, sesquiterpene hydrocarbons (SH) rose from approximately 7% in February to 19-22% in April, decreasing thereafter to approximately 9% in July. Oxygenated sesquiterpenes (SO) increased from a minimum of approximately 5% in July to a maximum of 8-11% in February, decreasing thereafter. The compounds that mostly accounted for the essential oil composition variation were alpha-pinene, beta-pinene, and camphene, as MH; alpha-thujone and camphor, as MO; alpha-humulene and beta-caryophyllene, as SH; and viridiflorol, as SO.  相似文献   

10.
We evaluated 17 plant essential oils and nine oil compounds for antibacterial activity against the foodborne pathogens Escherichia coli O157:H7 and Salmonella enterica in apple juices in a bactericidal assay in terms of % of the sample that resulted in a 50% decrease in the number of bacteria (BA(50)). The 10 compounds most active against E. coli (60 min BA(50) range in clear juice, 0.018-0.093%) were carvacrol, oregano oil, geraniol, eugenol, cinnamon leaf oil, citral, clove bud oil, lemongrass oil, cinnamon bark oil, and lemon oil. The corresponding compounds against S. enterica (BA(50) range, 0.0044-0.011%) were Melissa oil, carvacrol, oregano oil, terpeineol, geraniol, lemon oil, citral, lemongrass oil, cinnamon leaf oil, and linalool. The activity (i) was greater for S. enterica than for E. coli, (ii) increased with incubation temperature and storage time, and (iii) was not affected by the acidity of the juices. The antibacterial agents could be divided into two classes: fast-acting and slow-acting. High-performance liquid chromatography analysis showed that the bactericidal results are related to the composition of the oils. These studies provide information about new ways to protect apple juice and other foods against human pathogens.  相似文献   

11.
A gas chromatography flame ionization detection method for the quantification of bioactive marker compounds (neral, geranial, geraniol, limonene, citronellal, and beta-myrcene) in the essential oil of Cymbopogon citratus (lemon grass) was developed. Four procedures for the extraction of essential oils from C. citratus were compared including solvent extraction, steam distillation extraction, accelerated solvent extraction, and supercritical fluid extraction. Solvent extraction by sonication with nonpolar solvents showed comparable results to the steam distillation method. Several commercial products prepared from C. citratus and Cymbopogon flexuosus were analyzed and compared.  相似文献   

12.
The essential oil of leaves and peel from the Cretan variety Zambetakis (Citrus limon) was obtained by steam distillation with a Clevenger apparatus. The essential oil was subjected to GC-MS analysis, and 35 substances were identified. The main component in both essential oils was limonene. beta-Pinene, myrcene, neral, geranial, neryl acetate, geranyl acetate, and beta-caryophyllene have been identified in the leaf oil. The peel oil contained gamma-terpinene, beta-pinene, myrcene, neral, and geranial. The quantification of volatile substances was based on the internal standard method, using octyl acetate as internal standard, and expressed in milligrams per kilogram of the essential oil. The high contents of neral and geranial were indicative of the high quality of both essential oils. The aroma profile and quantitative variations among the essential oil components were measured at six different time intervals over a period of greater than one year. Differences between the components of lemon leaves and peel were observed.  相似文献   

13.
The fresh yields, the essential oil content, and the quality of a sage hybrid (Salvia officinalis x Salvia fruticosa, cv. Newe Ya'ar No. 4, Lamiaceae) as affected by development and harvest time were determined. Marked increases in plant height and in the number of nodes developed per plant together with a modest increase in leaf size were accompanied by dramatic increases (more than 20-fold) in the fresh yields throughout a 50-day growth period. No major changes in the essential oil content per fresh weight and its composition were detected throughout the growth period. In contrast, the compositions of the essential oils obtained from stems, as compared to leaves and leaf-primordia, had marked differences. Developmentally controlled changes in the extractives from individual leaf pairs from the same plant were also noted. In upper young leaves, the oxygenated diterpene manool and the sesquiterpene hydrocarbons alpha-humulene and beta-caryophyllene constituted up to 20%, 8%, and 4% of the total extractives, respectively. In older leaves, the abundance of these components steadily dropped to roughly half their levels in young leaves. Conversely, the proportions of the monoterpenes, particularly the ketones camphor and alpha-thujone, steadily increased with leaf position. Minor changes in the levels of other extractives were also recorded. These studies imply independent regulatory patterns for di-, sesqui-, and monoterpenes in this sage hybrid, and suggest possible agrotechnical means to obtain preferred chemical compositions of its essential oil.  相似文献   

14.
Ginger is widely used as either a food product or an herbal medicine in the world. In this paper, a method was developed for determining volatile components in essential oils from both dried and fresh ginger by use of gas chromatography-mass spectrometry (GC-MS) and chemometric approaches. With the resolution improvement by chemometric methods upon two-dimensional data from GC-MS, the drifting baseline can be corrected. In addition, the peak purity can be assessed and the number of chemical components and their stepwise elution in the peak clusters can be identified. The peak clusters investigated are then resolved into pure chromatograms and related mass spectra for each of the components involved. Finally, with the pure chromatograms and related mass spectra obtained, the chemical components can be qualitatively identified based on the similarity searches in the MS databases and the chromatographic retention times. Quantitative determination can be conducted using the overall volume integration approach. The results showed that 140 and 136 components were separated and that 74 and 75 of them were tentatively identified, which accounted for about 62.82 and 47.11% of the total relative content for dried and fresh ginger, respectively. In comparison with the chromatographic fingerprints of essential oils from dried and fresh ginger, 60 of the volatile components determined match with each other. The study demonstrated that the use of chemometric resolution based on two-dimensional data can mathematically enhance the separation ability of GC-MS and assist qualitative and quantitative determination of chemical components separated from complicated practical systems such as foods, herbal medicines, and environmental samples.  相似文献   

15.
In an effort to provide a better understanding of the sources of petroleum hydrocarbons in urban runoff, petroleum products as well as probable source materials were analyzed for hydrocarbons and trace metals and then compared to urban runoff samples from four different land use areas. The petroleum products considered were No. 2 and No. 6 fuel oils, used and virgin crankcase oils, and gasoline. Source materials included street dust, roadside soil, roadside vegetation, and atmospheric fallout; and the land use categories were commercial, residential, interstate highway, and industrial areas. The samples were compared on the basis of hydrocarbon (saturated and aromatic) and trace metal (Cd, Pb, Mn, Cu, Fe, Zn) loadings and distributions. Results indicated that the hydrocarbon content in runoff at all four land use sites originated primarily from used crankcase oil, with a small amount of No. 2 fuel oil detected at the industrial site. Only a small portion of the crankcase oil component came from the sources surveyed, and the majority of this oil probably came from: (1) oil drops within the driving lanes on the road surfaces or deposits in parking areas, and/or (2) direct dumping of waste crankcase oil down storm drains.  相似文献   

16.
Essential oils from the heartwood and leaves of specimens of Vanillosmopsis pohlii collected in two different localities were analyzed by GC-MS. The major constituent of both heartwood essential oils was the sesquiterpene alpha-bisabolol. Essential oil composition from leaves was quite different for two specimens and showed beta-pinene and E-caryophyllene as principal constituents. The essential oil of heartwood and the pure sesquiterpene alpha-bisabolol were tested against Bemisia argentifolii, the white fly fruit plague, and pronounced insecticidal effects were observed.  相似文献   

17.
The essential oil content and the composition of subterranean parts of two valerian (Valeriana officinalis, L.) cultivars Select and Anthose, from certified commercial organic fields, were determined by hydrodistillation, followed by gas chromatography (GC) and GC/mass spectrometry analysis. Eight and fourteen month old cv. Select had 0.67 and 0.87% essential oil, while similar aged cv. Anthose contained 0.97 and 1.1% essential oil. Forty-three and fifty-three components from cv. Select and cv. Anthose oils were detected, respectively. The oil composition significantly varied due to the cultivar type, plant age, and/or harvesting time. The major components for cv. Select were valerenal, bornyl acetate, 15-acetoxy valeranone, valerenic acid, and camphene, while cv. Anthose had valerenal, (-)-bornyl acetate, alpha-humulene, camphene, 15-acetoxy valeranone, and valerenic acid. With further aging of the plants, the valerenal, valerenic acid, and alpha-humulene contents increased. The oil of cv. Select had a strong antimicrobial effect against Aspergillus niger, Escherichia coli, Staphylococcus aureus, and Saccharomyces cerevisiae, while cv. Anthose showed low or no activity against all test microbes, including Pseudomonas aeruginosa, suggesting that the inhibitory activity of valerian oil depends on the cultivar and its developmental stage. The oil profile of our cultivars did not match the literature proposed chemotype profiles.  相似文献   

18.
The relationship between the content of nonesterified polyunsaturated fatty acids and the contents of oil aroma compounds that arise during the process to obtain virgin olive oil (VOO) was studied in two olive cultivars, Picual and Arbequina, producing oils with distinct aroma profiles and fatty acid compositions. Results suggest that the biosynthesis of VOO aroma compounds depends mainly on the availability of nonesterified polyunsaturated fatty acids, especially linolenic acid, during the process and then on the enzymatic activity load of the lipoxygenase/hydroperoxide lyase system. Both availability of substrates and enzymatic activity load seem to be cultivar-dependent.  相似文献   

19.
Huajiao denotes the fruits of various species of Zanthoxylum in the plant family Rutaceare used for cooking. The two most commercially popular species are bungeanum (red huajiao) and schinifolium (green huajiao). Fresh huajiao has a very high content of essential oil, up to 11%, which is described as having fresh, spicy, floral, cooling, and green aroma notes. A comprehensive analysis of the essential oils by GC-MS using advanced peak deconvolution and data processing software, revealed many overlapping components. A total of 120 aroma compounds for each species has been found. In the essential oils, linalyl acetate (15%), linalool (13%), and limonene (12%) are the major components of red huajiao, whereas linalool (29%), limonene (14%), and sabinene (13%) are the major components of green huajiao. For estimation of the aroma contribution of individual components, a new concept, "aroma character impact value" (ACI), is introduced as the percentage of the ratio of the concentration of an aroma component to its odor threshold value. Despite the differences in major components, both species have six common compounds of top aroma character impact: linalool, alpha-terpineol, myrcene, 1,8-cineole, limonene, and geraniol. The tingling sensation of huajiao is caused mainly by the alkylamide hydroxy-alpha-sanshool. The tingling compound decomposes easily under hydrolytic conditions or under UV light.  相似文献   

20.
Lemon balm (Melissa officinalis L.) is a well-known aromatic and medicinal plant. Because of its proven sedative, spasmolytic and antiviral effects, it is often used in watery or alcoholic extracts for self-medication or pharmaceutical purposes. Its therapeutic effect is due to the content of essential oil and rosmarinic acid. A set of 28 balm accessions was evaluated for the variability of essential oil content and composition and the content of rosmarinic acid. For analysis of secondary metabolites distillation, gas chromatography and high performance liquid chromatography was used. The content of essential oil in the first cut of the years 2009 and 2010 varied in this study in a range between 0.02 and 0.48% and in the second cut between 0.01 and 0.72%. The rosmarinic acid content of the collection ranged in the year 2009 for the first cut from 3.99 to 8.78% and in the second cut from 2.45 to 6.78%. Ploidy was determined for all accessions and two cytotypes were found: diploid 2n = 2x = 32 (15 accessions), tetraploid 2n = 4x = 64 (13 accessions). Via statistical analyses two chemotypes of essential oil were found: chemotype citral and chemotype germacrene D.  相似文献   

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