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Volatile Content (volatile + content)
Selected AbstractsRelation between Developmental Stage, Sensory Properties, and Volatile Content of Organically and Conventionally Grown Pac Choi (Brassica rapa,var.JOURNAL OF FOOD SCIENCE, Issue 4 2010Mei Qing Choi) ABSTRACT:, This study was conducted to identify and quantify the sensory characteristics and chemical profile of organically and conventionally grown pac choi (Brassica rapa,var. Mei Qing Choi), also called bok choy, at 3 stages of growth (2.5, 4.5, and 6.5 wk). Sensory and instrumental data were correlated using partial least squares regression. Pac choi was grown in late spring. Descriptive sensory analysis was conducted by a highly trained panel and compounds were identified and quantified using a gas chromatograph/mass spectrometer. The findings of the study indicate that the differences in sensory characteristics and chemical profiles among stages of growth are more substantial than the differences between organic and conventional production. Green-unripe, musty/earthy, lettuce, and sweet flavors are representative in pac choi at early stages of growth. When older, pac choi has higher intensities of green-grassy/leafy, bitter, cabbage, and sulfur flavors that are associated with the increase of (Z)-3-hexen-1-ol, octyl acetate, 1-nonanol, 2-decanone, 1-penten-3-ol, linalool, camphor, menthol, isobornyl acetate, geranylacetone, and cedrol compounds. Conventional pac choi was higher than organic pac choi in green overall, bitter, and soapy flavors only at 2.5 wk of age. This may be associated with the presence of (Z)-3-hexenal, 2-hexyn-1-ol, and (E)-2-hexenal compounds. Practical Application: The increased popularity of organic production has amplified the need for research that will help in understanding how this production system affects the final quality of food products. This study suggests that the stage of development has a much larger impact on sensory quality than organic or conventional growing of pac choi. Findings from this study promote consumer choice by showing that comparable sensory quality can be obtained using either production system, making the ultimate choice not only based on sensory quality but consumer choice related to environmental beliefs or economics. [source] Chemical composition of the essential oil from Vernonia scorpioides (Asteraceae)FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2007Maria Rose Jane R. Albuquerque Abstract The essential oil from aerial parts of Vernonia scorpiodes was obtained by hydrodistillation in a Clevenger-type apparatus. Qualitative and quantitative analysis were performed by GC,FID and GC,MS, respectively. A total of 18 compounds, representing 95.3% of the total volatile content, were identified. The major components found were , -caryophyllene (30.6%), germacrene D (27.3%), and bicyclogermacrene (8.5%). Copyright © 2007 John Wiley & Sons, Ltd. [source] Quantitative analysis of the volatile aroma components of pepino fruit by purge-and-trap and gas chromatographyJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2002Francisco Ruiz-Beviá Abstract A system specifically designed for the analysis of volatile organic compounds in water, called the purge-and-trap sample concentrator, has been set up to quantify the volatile aroma constituents of fruits. The technique shows some advantages over other conventional and new methods. The quantification of the major volatile compounds (3-methyl-2-buten-1-ol, 3-methyl-3-buten-1-ol and their acetates) of different pepino fruit samples has been performed using the purge-and-trap method. Relationships between the volatile content and the characteristics of fruits have been established. © 2002 Society of Chemical Industry [source] Layered ejecta craters and the early water/ice aquifer on MarsMETEORITICS & PLANETARY SCIENCE, Issue 1 2009Verne R. OBERBECK The impact model provides estimates of the water content of crater deposits relative to volatile content in the aquifer of Mars. These estimates together with the amount of water required to initiate fluid flow in terrestrial debris flows provide an estimate of 21% by volume (7.6 × 107km3) of water/ice that was stored between 0.27 and 2.5 km depth in the crust of Mars during Hesperian and Amazonian time. This would have been sufficient to supply the water for an ocean in the northern lowlands of Mars. The existence of fluidized craters smaller than 5 km diameter in some places on Mars suggests that volatiles were present locally at depths less than 0.27 km. Deposits of Martian craters may be ideal sites for searches for fossils of early organisms that may have existed in the water table if life originated on Mars. [source] Seasonal, populational and ontogenic variation in the volatile oil content and composition of individuals of Origanum vulgare subsp.PHYTOCHEMICAL ANALYSIS, Issue 5 2004Hirtum, assessed by GC headspace analysis, by SPME sampling of individual oil glands Abstract Small-scale GC headspace analyses combined with SPME sampling of individual oil glands have been used to measure the variation in volatile content and composition in and within different oregano plants as affected by age, season and developmental state. The main monoterpenes found were p -cymene, carvacrol and their precursor , -terpinene. The early season preponderance of p -cymene over carvacrol was reversed as the season progressed and this pattern could also be seen at any time within the plant, from the latest leaves to be produced (low in cymene) to the earliest (high in cymene). Seedlings from the same mother plant developed this pattern at different rates. Within individual leaves the pattern was not observed, even within the youngest developing leaves. However it was found that the oil composition of individual glands within a single leaf varied considerably, most notably in respect of the production of carvacrol and its isomer thymol. Copyright © 2004 John Wiley & Sons, Ltd. [source] NOx emissions of an opposed wall-fired pulverized coal utility boilerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010Xiaotao Gao Abstract The present paper was addressed to the effects of operational variables and coal properties on NOx emission level of a 600-MW opposed wall-fired pulverized coal utility boiler. The in situ experiments were performed to study the effects of operational variables on boiler performance by changing individual variables while the other variables were held nearly constant on the basis of the nominal load operation. It was found that the oxygen level was a significant parameter to affect the NOx emission. The impacts of coal properties on NOx emission indicated that NOx emission level decreased with the increase of the ratio of the nitrogen content to low heating value because the volatile matter content in coal significantly influenced the in-flame NOx formation. Coal volatile content was the dominant parameter to affect fuel NOx formation through affecting the reducing condition in the inner near-burner zone when the low NOx burners were applied in the boiler. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Development of a Novel Whey Beverage by Fermentation with Kefir Granules.BIOTECHNOLOGY PROGRESS, Issue 4 2004Effect of Various Treatments The development of a novel whey-based beverage with acceptable organoleptic properties is reported, where various treatments were studied. Kefir yeast immobilized on delignified cellulosic materials (DCM) or gluten pellets proved to accelerate whey fermentation significantly, with the latter support being not so preferable. Kefir granules seemed to achieve similar fermentation times as DCM. The final pH of the product is suggested to be 4.1 since the profile of the volatile byproducts was higher than other pH values tested. The addition of fructose seemed to be beneficial on the volatile content of the product, although its acceptability as determined by a preference panel was similar to that of the control. Finally, black raisin extract appeared to promote fermentation without any positive effect on the preference of the evaluators. [source] Variations in fluid activity across the Etive thermal aureole, Scotland: evidence from cordierite volatile contentsJOURNAL OF METAMORPHIC GEOLOGY, Issue 3 2008M. J. RIGBY Abstract The H2O and CO2 content of cordierite was analysed in 34 samples from successive contact metamorphic zones of the Etive thermal aureole, Scotland, using Fourier-transform infrared spectroscopy (FTIR). The measured volatile contents were used to calculate peak metamorphic H2O and CO2 activities. Total volatile contents are compared with recently modelled cordierite volatile saturation surfaces in order to assess the extent of fluid-present v. fluid-absent conditions across the thermal aureole. In the middle aureole, prior to the onset of partial melting, calculated aH2O values are high, close to unity, and measured volatile contents intersect modelled H2O,CO2 saturation curves at the temperature of interest, suggesting that fluid-present conditions prevailed. Total volatile contents and aH2O steadily decrease beyond the onset of partial melting, consistent with the notion of aH2O being buffered to lower values as melting progresses once free hydrous fluid is exhausted. All sillimanite zone samples record total volatile contents that are significantly lower than modelled H2O,CO2 saturation surfaces, implying that fluid-absent conditions prevailed. The lowest recorded aH2O values lie entirely within part of the section where fluid-absent melting reactions are thought to have dominated. Samples within 30 m of the igneous contact appear to be re-saturated, possibly via a magmatically derived fluid. In fluid-absent parts of the aureole, cordierite H2O contents yield melt,H2O contents that are compatible with independently determined melt,H2O contents. The internally consistent cordierite volatile data and melt,H2O data support the conclusion that the independent P,T estimates applied to the Etive rocks were valid and that measured cordierite volatile contents are representative of peak metamorphic values. The Etive thermal aureole provides the most compelling evidence, suggesting that the cordierite fluid monitor can be used to accurately assess the fluid conditions during metamorphism and partial melting in a thermal aureole. [source] | ||||||||||