Ethyl Hexadecanoate Research Articles

Preparation and aroma analysis of Chinese traditional fermented flour paste

Volatile compounds in Chinese fermented flour paste were extracted using simultaneous distillation and extraction (SDE) and analyzed using gas chromatography-mass spectrometry (GC-MS) with DB-5 and DB-WAX capillary columns. A total of 84 volatile compounds were identified, including 8 aldehydes, 19 esters, 14 acids, 17 hydrocarbons, 7 heterocycles, and 19 other trace compounds. The major volatiles included furfural, 5-methyl-2-phenyl-2-hexenal, 4-ethylguaiacol, 2-phenylacetaldehyde, ethyl hexadecanoate, isovaleraldehyde, palmitic acid, and 5-methylfurfural. Aroma compounds were investigated using gas chromatography-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). A total of 27 olfactory regions were exposed and 18 aroma extracts were located. Altogether, 6 aroma compounds identified using GC-O showed higher flavor dilution factors (FD≥32), including isovaleraldehyde, furfural, pentanoic acid, 2-acetylfuran, 1-octen-3-ol, and 2-phenylacetaldehyde. Compared with soybean sauce, fermented flour paste has more esters and aldehydes, which contribute to the desired fruity, caramel, sweet, and roasted odors.

Phytotoxic activity and phytochemical characterization of Lotus ornithopodioides L., a spontaneous species of Mediterranean area

The search of new bioactive compounds produced by plants represented an eco-friendly and alternative strategy in sustainable agriculture. In this context, the aerial parts of Lotus ornithopodioides L. (Fabaceae), annual herbaceous plant of Mediterranean area, were collected in Calabria (Southern Italy). Leaves and stems of L. ornithopodioides were extracted with methanol and subsequently bio-fractionated with n-hexane, chloroform and ethyl acetate. In vitro assays on germination and root growth of lettuce (Lactuca sativa L.) were performed to evaluate the phytotoxicity of the methanolic extract and its fractions, by a dose–response curve, comparing the ED50 values. Then, the most bioactive fractions were characterized through GC–MS. The crude methanolic extract strongly inhibited both processes showing, after 48h of treatment, ED50 values equal to 9.01 and 1.16 mg/ml for germination and root growth, respectively. The bioguided-fractionation showed the following hierarchy of phytotoxicity for both processes: ethyl acetate>chloroform≥n-hexane. A large amount of phenolic compounds were found in the ethyl acetate fraction (522mg/g of dry fraction) and some of them have been characterized through HPLC analysis. On the other hand, the n-hexane and chloroform fractions showed the presence of many semiochemicals, such as phytone, methyl hexadecanoate, ethyl hexadecanoate, methyl octadecanoate and 4-methyl-2-heptanone. These results make L. ornithopodioides L. a suitable source of natural compounds potentially usable as natural herbicides. Further studies will be necessary to understand the phytotoxic mechanisms of these molecules, alone or in combination and their effects on green-house and field experiments.

Effects of Ethanol and Long-Chain Ethyl Ester Concentrations on Volatile Partitioning in a Whisky Model System

Ethanolic atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was used to analyze the headspace concentrations of a test set of 14 whisky volatile compounds above a series of aqueous ethanolic solutions differing in alcohol content (5-40% ABV) and with regard to concentration of ethyl hexadecanoate (0-500 mg/L). The latter was selected to represent the long-chain ethyl esters found at various concentrations in new-make spirit. Headspace ion intensities were modeled against ethanol and ethyl hexadecanoate concentrations as factors. A separate model was prepared for each compound. Not surprisingly, ethanol content in the range of 5-40% ABV had a significant effect (P < 0.0001) on headspace volatile concentrations of all volatile compounds, whereas the ethyl hexadecanoate concentration had a selective effect of reducing headspace concentrations of the more hydrophobic compounds (log P > 2.5). This finding is discussed in terms of the "structuring" effects of ethyl hexadecanoate when present above critical micelle concentration, leading to the selective incorporation of hydrophobic volatile compounds into the interior of micelle-like structures. Data presented illustrate that dilution of whiskies to 23% ABV for "nosing" in the presence of long-chain ethyl esters is likely to change the balance of volatile compounds in the headspace and thus the perceived aroma character.

Renewable Oil Extracted from Indonesian Srikaya’s (Annona squamosa sp.) Seed: Another Potent Source for Biodiesel

This study looks at the wastes derived from Indonesian fruit as prospect for biofuels. This report investigates the chemical composition of Srikaya ( Annona squamosal sp.) seed, which is disposed as waste products from traditional markets. The seeds were extracted with various extraction methods and the oil obtained was analysed by means of gas chromatography (GC/FID), gas chromatography-mass spectrometry (GC/MS), infra-red spectrometry and ultra-violet-visible spectrometry. It was found 2 h extraction using soxhlet apparatus with diethyl ether as solvent gave the optimum time extraction. Moreover, five major components were isolated from i.e.: ethyl hexadecanoate, ethyl hexadec-9-enoate, ethyl octadecanoate, 2-hydroxy-1,3-propanediyl hexadecanoate, octadec-9-enaldehyde, and unknown compound, respectively.

Volatile constituents of roasted tigernut oil (Cyperus esculentus L.)

Volatile compounds play a key role in determining the sensory appreciation of vegetable oils. In this study a systematic evaluation of odorants responsible for the characteristic flavour of roasted tigernut oil was carried out. A total of 75 odour-active volatiles were identified. From these, 13 aroma compounds showing high flavour dilution factors in the range of 16 to 128 were quantified by their odour activity values (OAVs). On the basis of high OAVs in oil, the following aroma compounds [vanillin (chocolate, sweet vanilla), 5-ethylfurfural (caramel, spicy), 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (caramel), phenyl acetaldehyde (honey-like), ethanone, 1-(4-hydroxy-3-methoxyphenyl) (faint vanilla)] were elucidated as important contributors to the overall chocolate, sweet vanilla, butterscotch aroma of the oil. Odorants with high concentrations in the roasted tigernut oil such as 5-hydroxymethylfurfural, ethyl hexadecanoate, n-propyl-9,12-octadecadienoate gave relatively low OAVs, so their contributions to the overall orthonasal aroma impression of roasted tigernut oil can be assumed to be low.

Evaluation of antifungal activity of seaweed extracts

Seaweeds are subject to numerous biological interactions and sometimes to extreme abiotic conditions, so they have developed among other defense mechanisms, the ability to produce biologically active substances. Thus, these organisms produce mainly terpenes and phenols. Among others, the antifungal activity, due to its importance in human and animal health and the production of agricultural products, has been the subject of several studies. In the present work, this activity was investigated in ten seaweeds extracts, by direct bioautography assays, compared to Colletotrichum lagenarium and disk diffusion assay, compared to Aspergillus flavus. The organisms studied were: Stypopodium zonale, Laurencia dendroidea, Ascophyllum nodosum, Sargassum muticum, Pelvetia canaliculata, Fucus spiralis, Sargassum filipendula, Sargassum stenophyllum, Laminaria hyperborea and Gracilaria edulis. S. zonale, L. dendroidea, P. canaliculata, S. muticum, A. nodosum and F. spiralis extracts significantly inhibited the C. lagenarium growth, but not inhibited significantly the A. flavus growth. The presence of terpenes in all of these extracts was confirmed by thin layer chromatography whereas the presence of phenolic compounds was confirmed only in extracts of P. canaliculata, A. nodosum and S. muticum. In chemical study by column chromatography, followed by gas chromatography/mass spectrometry analysis, the terpenes neophytadiene, cartilagineol, obtusol elatol; and the ester ethyl hexadecanoate were identified in the L. dendroidea extract. This is the first report on the activity of seaweed extracts against C. lagenarium, a fungus bearing agricultural importance.

Effects of cement dust on volatile oil constituents and antioxidative metabolism of Aleppo pine (Pinus halepensis) needles

The effects of cement dust on the chemical composition of essential oil, lipid peroxidation and antioxidant enzyme activities of Aleppo pine (P. halepensis) needles were studied. Cement dust resulted in a significant decrease in the yield of essential oil with the effect being more pronounced in the close vicinity of the cement factory. A concomitant decrease in all components of the oil was observed and δ-2-carene, trans-carveol, trans-carvyl acetate, α-terpinyl acetate, β-copaene, (E,E)-α-farnesene, α-calacorene, α-cadinene, spathulenol, humulene oxide II, 8-epi-γ-eudesmol, Ί-muurolol, cubenol and ethyl hexadecanoate have been proposed as biological indicators of cement dust. Moreover, a redirection of the secondary metabolism toward the biosynthesis of monoterpenes has been evidenced. Malondialdehydes (MDA), a decomposition product of polyunsaturated fatty acids, often considered as a suitable biomarker for lipid peroxidation was induced in the needles exposed to cement dust. Similarly, a remarkable induction of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities was noticed. The positive relationships were observed among activities of antioxidant enzymes, and between MDA content and activities of antioxidant enzymes, indicating the cooperative action of these antioxidant enzymes to cope with the oxidative stress induced by cement dust. The results obtained indicate that P. halepensis needles are useful bio-monitors of cement dust pollution.

Essential Oil Composition of Ephedra nebrodensis Tineo ex Guss. subsp. nebrodensis from Central Italy

The essential oil of Ephedra nebrodensis Tineo ex Guss. subsp. nebrodensis growing in central Italy was analyzed for the first time by GC and GC/MS. Fifty-nine components were identified, representing 89.3% of the oil under study. The oxygenated monoterpenes gave the highest contribution (33.0 %), and citronellol (29.7%) was the main component of this fraction. Esters were the second most abundant group of components (18.8%) with ethyl hexadecanoate (9.5%) as the main representative in this fraction. Qualitative and quantitative composition of the oil was discussed in order to support the actual botanical discrimination from E. major Host, so far exclusively morphologically based.

Phytochemical screening and biological activities of the oil components of Prunus domestica Linn

Phytochemical screening of three different oil fractions, obtained from n-hexane extract of Prunus domestica shoots were analyzed by GC and GC–MS. It resulted in the identification of 9, 16 and 24 compounds which representing 92.56%, 90.6% and 90.69% of these oil fractions, respectively. The main components identified from fraction 1, 2 and 3 were hentricontane (35.7%), ethyl hexadecanoate (21.7%) and linoleic acid (16.16%), respectively. Bioassay screening of oil showed moderate antibacterial activity against Salmonella group (Gram +ve and −ve) by agar well diffusion method, moderate antifungal activity against Microsporum canis by agar tube dilution method and good antioxidant activity by DPPH radical scavenging method.

Chemical Composition and Antioxidant Activity of the Essential Oil From Oxytropis falcate Bunge

The antioxidant activity of the essential oil from Oxytropis falcate Bunge was determined spectrophotometrically using the 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) while the oil was analyzed by GC and GC/MS. The oil exhibited an IC50 value at 0.17 mg/mL. Analysis revealed that 50 compounds were identified, consisting 89.0% of the total oil. Viridiflorol (11.5%), (E)-nerolidol (8.2%), ethyl hexadecanoate (6.5%), tricosane (5.6%) and spathulenol (5.4%) were the major components of the oil.

The Volatile Organic Compounds from Tepals and Anthers of Saffron Flowers (Crocus sativus L.)

The ethanolic extracts of tepals and anthers of saffron fowers (Crocus sativus L.) were analyzed by means of GC and GC/MS. The extract from tepals contained 16 compounds, the most abundant were 2-phenylethyl alcohol (15.0%), tetracosane (10.5%), ethyl hexadecanoate (10.0%) and heptadecane (9.6%). The extract from anthers contained 26 compounds, the major compounds being 2-phenylethyl alcohol (50.4%) and 2-phenethyl acetate (15.4%).

Composition of the essential oils of Lycium barbarum and L. ruthenicum fruits

Water-distilled essential oils from the fruits of Lycium barbarum and L. ruthenicum were analyzed by GCMS. The main components in the oil of L. barbarum were found to be hexadecanoic acid (47.5%), linoleic acid (9.1%), β-elemene (5.4%), myristic acid (4.2%), and ethyl hexadecanoate (4.0%). The essential oil of L. ruthenicum has heptacosane (14.3%), ethyl linoleate (10.0%), hexacosane (7.0%), nonacosane (6.2%), and ethyl hexadecanoate (5.8%) as the main compounds.

Essential Oil Composition of Lawsonia inermis L. Leaves from Nigeria

The essential oil of the leaves of Lawsonia inermis L. (henna) was analyzed by GC and GC/MS. Thirty-six components, which constituted 80.4% of the oil, were identified. The major components were ethyl hexadecanoate (24.4%), (E)-methyl cinnamate (11.4%), isocaryophyllene (8.1%), (E)-β-ionone (5.8%) and methyl linolenate (4.1%).

Sesquiterpene Lactones from Elephantopus scaber.

The ethanolic and acetone extracts of the whole plant of Elephantopus scaber were found to contain ethyl hexadecanoate, ethyl-9,12-octadecadienoate, ethyl-(Z)-9-octadecenoate, ethyl octadecanoate, lupeol, stigmasterol, stigmasterol glucoside, deoxyelephantopin (1) and two new germacranolide sesquiterpene lactones named 17,19-dihydrodeoxyelephantopin (2) and iso-17,19- dihydrodeoxyelephantopin (3) whose stereostructures were determined by spectroscopic methods, comparison with reported data and single-crystal X-ray analysis.

Sesquiterpene Lactones from Elephantopus scaber

The ethanolic and acetone extracts of the whole plant of Elephantopus scaber were found to contain ethyl hexadecanoate, ethyl-9,12-octadecadienoate, ethyl-(Z)-9-octadecenoate, ethyl octadecanoate, lupeol, stigmasterol, stigmasterol glucoside, deoxyelephantopin (1) and two new germacranolide sesquiterpene lactones named 17,19-dihydrodeoxyelephantopin (2) and iso-17,19- dihydrodeoxyelephantopin (3) whose stereostructures were determined by spectroscopic methods, comparison with reported data and single-crystal X-ray analysis.

Impact of Storage of Freshly Harvested Paddy Rice on Milled White Rice Flavor

ABSTRACTBetween harvest and the start of drying, paddy rice may be held for more than 24 hr at moisture contents ranging from 16% to &gt;26%. Microbes found on the freshly harvested rice grow under these conditions and produce a wide variety of volatile compounds that impact the flavor/aroma of the white rice obtained after drying and milling of the paddy rice. The contents of 10 volatile microbial metabolites were compared in white rice obtained from paddy rice harvested at differing moisture contents and immediately dried (0 hr) or held for 48 hr before drying. No increases in volatile microbial metabolite levels were observed in white rice obtained from paddy rice that was stored at 17–21% moisture contents for 48 hr. In white rice from paddy rice stored at ≥24% moisture content, 3‐methyl‐butanol, 2‐methyl‐butanol, acetic acid, 2,3‐ butandiol, and ethyl hexadecanoate increased markedly with time. Also in these samples, as determined by a descriptive panel, sour/silage and alfalfa/grassy/green bean flavors significantly increased (P &lt; 0.1) in intensity. Sour/silage, the predominant off‐flavor note in the stored samples, correlated highly (r = 0.98) with 2,3‐butandiol. Ethanol concentration measurements on the paddy rice correlated highly with sour/silage (r = 0.99) and 2,3‐butandiol (r = 0.97), and correlated well with several other volatile microbial metabolites. Carbon dioxide measurements taken on the paddy rice did not correlate as highly (r =.78) with sour/silage. Measurements of ethanol produced in paddy rice may serve as an indicator of off‐flavor/aroma development in the resultant white rice.

Analysis of insecticidal Azadirachta indica A. Juss. fractions.

As a result of chemical investigation on the ethanolic extract of fresh fruit coatings of Azadirachta indica A. Juss. (neem), twenty-seven compounds were identified in non-polar to less polar fractions which showed pesticidal activity determined by WHO method against Anopheles stephensi Liston. These identifications were basically made through GC-EIMS and were further supported by other spectroscopic techniques, including 13C NMR, UV and FTIR as well as retention indices. Thus sixteen n-alkanes, 1-16; three aromatics 2,6-bis-(1,1-dimethylethyl)-4-methyl phenol (17), 2-(phenylmethylene)-octanal (20), 1,2,4-trimethoxy-5-(1Z-propenyl)-benzene (27); three benzopyranoids 3,4-dihydro-4,4,5,8-tetramethylcoumarin (18), 3,4-dihydro-4,4,7,8-tetramethylcoumarin-6-ol (19), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta[g]-2-benzopyran (22); one sesquiterpene methyl-3,7,11-trimethyl-2E,6E,10-dodecatrienoate (21); three esters of fatty acids methyl 14-methyl-pentadecanoate (23), ethyl hexadecanoate (24), ethyl 9Z-octadecenoate (25) and one monoterpene 3,7-dimethyl-1-octen-7-ol (26) were identified. Except 6, 8, 24 and 25 all these compounds were identified for the first time from the pericarp and fifteen of these, 1-3, 7, 9, 10, 17-23, 26, 27, are hitherto unreported previously from any part of the tree. Although this tree is a rich source of various natural products, it is the first report of identification of mono- and sesquiterpenes 26 and 21 and a potent antioxidant, 17.

Electrophysiological responses of female and male Hypsipyla grandella (Zeller) to Swietenia macrophylla essential oils.

The mahogany shoot borer, Hypsipyla grandella, is one of the most economically important Neotropical forest pest insects because it attacks valuable timber of the Meliaceae. Despite detailed information on the life cycle of H. grandella, factors influencing attack by the shoot borer are not well known. Electroantennogram studies of borer antennae indicate that both female and male moths elicited significant antennal responses to essential oil of the terminal shoots, mature and senescent leaves, in three concentrations. Gamma-himachalene, germacrene D, germacrene A, cadina-1,4-diene, hexadecanoic acid, and ethyl hexadecanoate appeared in all essential oils from Swietenia macrophylla. Germacrene-D and gamma-himachalene were also present in the active essential oil of Cedrela odorata and Toona ciliata. These findings suggest that these compounds play a role in attracting H. grandella to oviposit on the leaves of these plants. The GC-EAD of essential oil from S. macrophylla mature leaves to female H. grandella antennae led to the identification of beta-caryophyllene as the main constituent responsible for the antennae response.

Analysis by GC–MS of the hexane extract of the aerial parts of Aristolochia acutifolia Duchtr.

Qualitative analysis by GC–MS of the three non-polar fractions from the hexane extract of Aristolochia acutifolia Duchtr. was carried out and 47 constituents were identified. The major groups of constituents identified away these fractions were sesquiterpenes (spathulenol, 23.1%; β-bisabolene, 9.0%; α-eudesmol, 6.9%; α-selinene, 5.2%; and trans-α-bergamotene, 5.1%), esters (ethyl hexadecanoate, 23.0%; ethyl 9-octadecenoate, 11.6%; and methyl hexadecanoate, 7.9%), phenylpropanoids (myristicin, 35.3%; and elemicin, 15.8%), carboxilic acids (oleic, 22.8%; and palmitic acids, 20.3%), and n-alkanes (pentadecane, 11.7%). Some constituents identified are described for the first time in this genus. Copyright © 2001 John Wiley & Sons, Ltd.

Analysis by GC-MS of the hexane extract of the aerial parts ofAristolochia acutifolia Duchtr.

Qualitative analysis by GC–MS of the three non-polar fractions from the hexane extract of Aristolochia acutifolia Duchtr. was carried out and 47 constituents were identified. The major groups of constituents identified away these fractions were sesquiterpenes (spathulenol, 23.1%; β-bisabolene, 9.0%; α-eudesmol, 6.9%; α-selinene, 5.2%; and trans-α-bergamotene, 5.1%), esters (ethyl hexadecanoate, 23.0%; ethyl 9-octadecenoate, 11.6%; and methyl hexadecanoate, 7.9%), phenylpropanoids (myristicin, 35.3%; and elemicin, 15.8%), carboxilic acids (oleic, 22.8%; and palmitic acids, 20.3%), and n-alkanes (pentadecane, 11.7%). Some constituents identified are described for the first time in this genus. Copyright © 2001 John Wiley & Sons, Ltd.