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PubMedDate not supplied

Analysis of Rhioxma Curcumae Aeruginosae volatiles by solid-phase microextraction with gas chromatography-mass spectrometry.

In this paper, a headspace solid-phase microextraction (HS-SPME) method was applied to analyse the volatile compounds in a traditional Chinese medicine (TCM), Rhioxma Curcumae Aeruginosae. SPME parameters such as fibers, extraction temperature, extraction time and desorption time were investigated. Thirty-five volatile compounds were separated and identified. Relative standard deviations (RSDs) were less than 8.4%, showing that the method has a good reproducibility. The volatile constituents were also analyzed by steam distillation (SD) and thirty-seven compounds were identified. The similar results obtained by the two methods showed that SPME is a good alternative for the analysis of volatile constituents in Rhioxma Curcumae Aeruginosae samples and it is a relatively simple, rapid and solvent-free method.

Camphor↗
PubMedDate not supplied

An improved description of pesticide volatilization: refinement of the pesticide leaching model (PELMO).

The consideration of pesticide volatilization from soil surfaces as an integral component of pesticide fate models is of importance, especially as part of the Predicted Environmental Concentrations (PEC) models used in the registration procedures for pesticides. The Pesticide Leaching Model (PELMO), which is used in the European registration process, was modified to allow for a reliable prediction of volatilization from soil. The previous PELMO version was upgraded by improving the spatiotemporal discretization at the soil surface, improving the empirical description of temperature dependence of Henry's law constants and including increased sorption of pesticides in dry soils. Comparison of predictions with experimental findings revealed the improvements of PELMO to contribute to a more realistic reflection of measurements, particularly at initial stages of the studies. The broad range of literature values of Henry's law constants was shown to have a significant effect on predicted volatilization fluxes. As a main refinement, the tendency of pesticides toward enhanced volatilization under moist conditions was correctly calculated by the improved model. Variations between model predictions and measurements were due to a lack of experimental data on soil sorption under dry conditions and indicated the need for further calibration of the model. The description of water content in the top layer was subject to uncertainty, which was exemplified by an overestimation of soil moisture during the last days of the field study. Thus, future model improvement will be dependent on experimental support to obtain more detailed information on soil-air-water partitioning of pesticides in the top soil layer.

Forecasting↗
PubMed2004

Feeding encapsulated ground full-fat soybeans to increase polyunsaturated fat concentrations and effects on flavor volatiles in fresh lamb.

This research assessed the potential of increasing PUFA concentrations and the effect on flavor volatiles in red meat by feeding ground, full-fat soybean supplemented in casein complex. Supplements consisted of untreated ground, full-fat soybean (CO) or ground, full-fat soybeans treated with acetaldehyde (AC) or diacetyl (DA) to form gels. On a DM basis, the control (CO), AC, and DA supplements contained 48.6, 50.0, and 49.1% CP and 17.3, 17.3, and 17.4% fat, respectively. Weaned feeder lambs (n = 18) were divided into three treatment groups with two pens of three lambs per group. One of three supplements (200 g of DM) plus 1 kg DM of a ground corn basal diet and 0.36 kg DM of grass hay was fed daily to each of six lambs in a group for 9 wk. Samples of the intramuscular (LM), intermuscular, subcutaneous, and kidney fat were obtained from each lamb carcass for determination of total lipid contents and fatty acid profiles. Flavor volatiles of broiled LM were also analyzed. Total fat content of the LM was 3.7, 4.6, and 2.6% for lambs consuming diets supplemented with CO, AC, and DA, respectively. Compared with lambs fed the untreated supplement (CO), lambs supplemented with AC or DA had 1) higher (P < 0.05) concentrations of linoleic (4.80 vs. 6.37 or 6.80%) and linolenic (0.28 vs. 0.43 or 0.45%) acids in the LM nonpolar lipids; 2) a higher (P < 0.05) concentration of linoleic acid (22.1 vs. 27.1 or 25.6%), but a lower (P < 0.05) concentration of oleic acid (17.2 vs. 13.0 or 13.1%), in the LM polar lipids; 3) a higher (P < 0.05) concentration of linoleic acid (3.77 vs. 6.13 or 6.06%) in subcutaneous fat; and 4) higher (P < 0.05) concentrations of linoleic (4.46 vs. 7.65 or 7.13%), linolenic (0.50 vs. 0.85 or 0.80%), and stearic (24.9 vs. 27.2 or 26.9%) acids, but a lower (P < 0.05) concentration of oleic acid (39.1 vs. 35.4 or 36.3%), in kidney fat. In broiled LM chops, 21 volatiles were identified, including seven alkanals, seven 2-alkenals, two 2,4-alkadienals, and five other compounds, but most differences in the volatile concentrations among lambs fed the different supplements did not correspond to concentration differences in their precursor fatty acids. Results indicated that compared with the untreated supplement (CO), AC and DA supplements protected linoleic (C 18:2n6) and linolenic (C18:3n3) acids in soybean oil from degradation in the rumen of the lambs, resulting in increased deposition in the muscle and adipose tissues of lamb.

Acetaldehyde↗
PubMed2005

Sensory characteristics and related volatile flavor compound profiles of different types of whey.

To characterize the flavor of liquid whey, 11 samples of whey representing a wide range of types were sourced from cheese and casein-making procedures, either industrial or from pilot-plant facilities. Whey samples were assessed for flavor by descriptive sensory evaluation and analyzed for headspace volatile composition by proton transfer reaction-mass spectrometry (PTR-MS). The sensory data clearly distinguished between the samples in relation to the processes of manufacture; that is, significant differences were apparent between cheese, rennet, and acid wheys. For Mozzarella and Quarg wheys, in which fermentation progressed to low pH values, the starter cultures used for cheese making had a significant influence on flavor. In comparison, Cheddar and Gouda wheys were described by milk-like flavors, and rennet casein wheys were described by "sweet" (oat-like and "sweet") and thermally induced flavors. The volatile compound data obtained by PTR-MS differentiated the samples as distinctive and reproducible "chemical fingerprints". On applying partial least squares regression to determine relationships between sensory and volatile composition data, sensory characteristics such as "rancid" and cheese-like odors and "caramelized milk," yogurt-like, "sweet," and oat-like flavors were found to be related to the presence and absence of specific volatile compounds.

Caseins↗
PubMed2005

Influence of starter culture on flavor and headspace volatile profiles of fermented whey and whey produced from fermented milk.

Rennet whey and skim milk were compared as media for fermentation by commercial cheese, yogurt, and probiotic starter cultures. Effect of culture, medium, and their interaction on flavor was assessed and compared by sensory descriptive analysis and headspace volatile analysis by proton transfer reaction-mass spectrometry. In general, the aroma of fermented whey was similar to that of whey separated from fermented milk, indicating a favorable possibility of substituting milk with whey in the manufacture of fermented milk-like beverages. Starter culture significantly affected most sensory characteristics of the products. Key volatile compounds for the characteristic flavor of yogurt, such as acetaldehyde and diacetyl, were not significantly affected by medium when fermented with the yogurt culture, and reached similar levels in both systems. Volatile analysis results were consistent with the results of the sensory evaluation, indicating the high reliability of proton transfer reaction-mass spectrometry in detecting important volatile compounds for aroma. Integration of this sensory and chemical information allows a better understanding of how flavor and related compounds are affected by ingredients or processing, which may be useful for the development of value-added whey products.

Acetaldehyde↗
PubMed2006

Comparison of the compositional, microbiological, biochemical, and volatile profile characteristics of nine Italian ewes' milk cheeses.

Nine Italian ewes' milk cheeses were compared for compositional, microbiological, biochemical, and volatile profile characteristics. Mean values for the gross composition were rather similar among cheeses. The lowest pH values were found for cheeses that used primary starters. At the end of ripening, cheeses made from raw milk contained >6.0 log10 cfu/g of nonstarter lactic acid bacteria. Several species of lactobacilli were identified, but Lactobacillus plantarum and Lactobacillus paracasei were dominant. Random amplified polymorphic DNA-PCR analysis showed the biodiversity among the strains, and in several cases a relationship with the cheese of provenance. Cheeses differed mainly for secondary proteolysis, as shown by the principal component analysis applied to reversed-phase fast protein liquid chromatography data of the pH 4.6-soluble fractions and by determination of the free AA. A total of 113 volatile components were identified in the Italian Pecorino cheeses by solid-phase microextraction coupled with gas chromatography-mass spectrometry analysis. The volatile profiles of the 9 cheeses differed significantly. Quantitatively, alcohols were the most abundant chemical class for some cheeses, whereas ketones were the most abundant for other cheeses. Esters and carboxylic acids were largely found. Specific volatile components seemed to distinguish specific cheeses.

Amino Acids↗
PubMed1975

Volatile fatty acid metabolism by rumen mucosa from cattle fed hay or grain.

Effects of an all-grain versus an all-hay diet on metabolic activity of rumen mucosa of cattle were investigated. After diets had been fed for 3 to 4 mo, rumen papillae were collected at slaughter from the dorsal rumen sac and incubated with one of various volatile fatty acids. Rates of substrate utilization were in the order: n-butyrate greater than n-valerate approximately propionate greater than iso-butyrate approximately iso-valerate. Over-all, papillae from hay-fed steers utilized greater amounts of volatile fatty acids. Dietary treatment did not significantly affect extent of conversion of volatile fatty acids to lactate and to ketone bodies. Lactate was the major metabolite from propionate and n-valerate. Ketone body formation accounted for more than 90% of n-butyrate uptake by papillae. Ketone formation from n-valerate was restricted to beta-hydroxybutyrate while that from iso-valerate was essentially acetoacetate plus acetone. Metabolic systems in rumen mucosa of physiologically mature ruminants seem to adapt little to varying individual volatile fatty acids available for absorption in vivo.

Acetoacetates↗
PubMed1987

Effects of feeding or infusing ammonium salts of volatile fatty acids on ruminal fermentation, plasma characteristics, and milk production of cows.

Eight rumen-fistulated Holstein cows, averaging 77 d postpartum, were used in a replicated 4 X 4 Latin square design with 28-d periods to investigate the effect of ammonium salts of isobutyrate, 2-methylbutyrate, isovalerate, and n-valerate on animal performance and their possible mechanism(s) and site(s) of action. Each cow was fed ad libitum a complete mixed diet of 55% corn silage and 45% concentrate on a dry basis that was supplemented with 1.8 kg of premix daily. Treatments were 1) control, 2) ammonium salts of volatile fatty acids in premix, 3) ammonium salts of volatile fatty acids ruminally infused, or 4) ammonium salts of volatile fatty acids abomasally infused. Mean ruminal fluid pH and concentrations of ammonia and volatile fatty acids for treatment comparisons were not different. Plasma concentrations of isobutyrate, 2-methylbutyrate, and valerate differed among treatments, but there was no significant effect on dry matter intake, milk production, milk composition, or efficiency of feed utilization. Apparent nutrient digestibility; disappearance of dry matter, cellulose, and nitrogen from polyester bags suspended in the rumen; and plasma concentrations of glucose, free fatty acids, and growth hormone also were not significantly affected by treatment.

Abomasum↗
PubMed1999

Effects of dietary nitrogen manipulation on ammonia volatilization from manure from Holstein heifers.

Decomposition of livestock manure produces gaseous ammonia. Dietary manipulation is one means to reduce N in manure and ammonia volatilization. The effects of dietary crude protein concentration on N intake, N and urinary urea-N excretion, and ammonia volatilization were measured. Eight Holstein heifers (body weight = 260 to 488 kg) were fed a total mixed ration containing either 9.6 or 11.0% crude protein in a crossover design. Oatlage and concentrate were fed at 77:23 (dry matter basis), and soybean meal was used to alter total dietary crude protein. Seven-day adjustment periods preceded 5-d collection periods. Indwelling urinary catheters were inserted 2 d prior to the collection periods. Daily feces and acidified urine were collected, stirred, and subsampled for total Kjeldahl N, urinary urea N, dry matter, P, K, and ash. Urine collection tubes were split during period 2 to allow for collection of unacidified samples for urea N and total N determinations. Unacidified urine and fecal samples were combined (1:1.3) for collection of volatilized ammonia. Remaining slurries were extracted for total and urea N. Increased dietary crude protein concentration increased N intake, N excretion, urea-N excretion, and N excreted in the urine by the heifers. Dietary manipulation of N intake by reduction of 14.0% (dry matter basis) resulted in a 28.1% decrease in ammonia emission and decreases in the urea N, total N, and percentage N excreted in the urine of 29.6, 19.8, and 7.4%, respectively. Ammonia volatilization was dependent on N quantity and form in the urine.

Ammonia↗
PubMed1999

Volatile sulfur compounds in human expiration after eating raw or heat-treated garlic.

Volatile sulfur compounds arising from grated raw or heat-treated garlic in both in-vitro and in-vivo tests were gas-chromatographically analyzed. In in-vitro tests, the head-space vapor gas from garlic in a vial was analyzed. It was clarified that allyl mercaptan arising from raw garlic decreased with the passage of time and other volatile low-molecular sulfur compounds (LMSC) did not show remarkable changes. The change of LMSC from heat-treated garlic was also studied. Methyl mercaptan and allyl mercaptan from heat-treated garlic gradually increased to some extent. On the other hand, the quantities of somewhat high-molecular sulfur compounds (HMSC) were much less in heat-treated garlic compared to those of raw garlic. These compounds increased till approx. 60 min and then decreased gradually. In in-vivo tests, human expiration after eating garlic was analyzed. Allyl mercaptan, methyl mercaptan and allyl methyl sulfide in LMSC were detected in significant amounts. The quantities of these compounds arising from heat-treated garlic were smaller than those from raw garlic. These compounds had the tendency of decreasing with the passage of time. On the other hand, almost no HMSC was detected in both raw and heat-treated garlic. By sensory testing, raw garlic showed a stronger smell than heat-treated garlic in both in-vitro and in-vivo tests. GC analysis exhibited higher values of volatile sulfur compounds in raw garlic. That is, the higher the volatile sulfur compound level, the stronger the garlic flavor or malodor.

Allyl Compounds↗
PubMed2000

Volatile sulfur production by pig cecal bacteria in batch culture and screening inhibitors of sulfate reducing bacteria.

We studied the effects of specific inhibitors of methanogenesis (2-bromoethane sulfonate, BES) and sulfate reduction (sodium molybdate) on volatile sulfur production in batch cultures of pig cecal bacteria. The volatile sulfur concentration in headspace gas was determined by flame-photometric detector gas chromatography. BES stimulated production of hydrogen sulfide (H2S) and methanethiol, and sodium molybdate completely inhibited the production of these volatile sulfur compounds. The results indicated that dissimilate sulfate reduction is mainly responsible for volatile sulfur production in the hindgut. Therefore the extracts of herbs, food colors, and aroma chemicals were tested for their inhibitory effects on H2S production by a dissimilatory sulfate-reducing bacteria. Desulfovibrio desulfuricans DSM642. H2S was measured by the chromatography of the headspace gas, using a flame photometric detector. Of 306 herbal extracts tested, 69 extracts from 38 herbs inhibited H2S production at 1.0 mg/mL. Sisymbrium officinale (hedge mustard) was the most potent inhibitor. Six pigments inhibited H2S release. Erythrosine and rose bengal showed inhibitory effects at 0.01 mg/mL. Peppermint oil and 96 aroma chemicals were assayed for their effects on H2S release. Thirty-two aroma chemicals suppressed H2S production at 0.1 mg/mL, and camphene, 1-decanol, and 2-nonanone were effective at 0.01 mg/mL.

Alkanesulfonic Acids↗
PubMedDate not supplied

Evaluation of a hypercrosslinked polystyrene, MN-200, as a sorbent for the preconcentration of volatile organic compounds in air.

Breakthrough volumes, average percentage recoveries, and storage stabilities were obtained for vapors of 8 volatile organic compounds (pentane, octane, undecane, isooctane, cyclohexane, toluene, methanol, and dichloromethane) on a new adsorbent material, Hypersol-Macronet, MN-200. Breakthrough volumes were estimated as half of the gas chromatographic specific retention volumes at 20 degrees C for the compounds. Recoveries of the adsorbates were determined by both solvent extraction and thermal desorption methods. The results obtained compare favorably with those for Tenax GR (values reported in the published literature and others obtained in our laboratory). Results of storage stability studies on MN-200 meet the criterion for acceptability (<10% loss). High adsorption capacity for very volatile and polar compounds, combined with ease of desorption of less volatile compounds, render MN-200 a highly promising adsorbent for sampling volatile organic compounds in indoor and outdoor air.

Adsorption↗
PubMed2001

Intratracheal gas analysis for volatile substances by gas chromatography/mass spectrometry--application to forensic autopsies.

Intratracheal gas analysis was carried out by gas chromatography/mass spectrometry (GC/MS) in 20 burned body cases (13 males and 7 females). Volatile aromatic and aliphatic hydrocarbons were detected by GC/MS using a GS-Q column with the intratracheal gas as well as the blood in 19 cases. The characteristic patterns of mass chromatograms for gasoline, kerosene (gas oil), and liquid petroleum gas could be differentiated from each other using the intratracheal gas. The burned body in one case showed no presence of volatile substances in the intratracheal gas, nor intratracheal soot, although high concentrations (1 microg/g and more) of volatile substances were detected on the clothes. The victim also had normal CO-Hb concentrations (0.1 to 0.2%) in the heart blood. The results of intratracheal gas analysis were consistent with signs of the vital reaction. In conclusion, intratracheal gas analysis provides a supportive method for diagnosing the cause of death in burned bodies, and yields for at least 48 hours valuable information on volatile hydrocarbons (being detected in deliberate or accidental fire cases) to which the body had been exposed just before death.

Adolescent↗
PubMed1998

[Influence of fry-processing on outward character and inner quality of volatile oil containing drugs such as fructus Viticis, etc].

According to the requirement of outward character in processing traditional Chinese drugs, five volatile oil containing drugs Fructus Viticis, Rhizoma Atractylodis Macrocephalae, Rhizoma Cyperi, Fructus Foeniculi and Fructus Aurantii were fry-processed. The conditions of frying technology were measured; the amounts of volatile oil before and after processing were determined with accurate volatile oil extractor; and the volatile oil in Rhizoma Atractylodis Macrocephalae and Fructus Aurantii was analyzed by means of GC.

Apiaceae↗
PubMed2001

Creating anoxic and microaerobic conditions in sequencing batch reactors treating volatile BTX compounds.

An experimental strategy is introduced for studying the biodegradation of wastewaters containing volatile contaminants using an alternating anoxic/microaerobic sequencing batch reactor (SBR). Benzene, toluene, and the xylene isomers (BTX) served as model volatile contaminants for this study. The reactor was configured to overcome stripping the volatile BTX compounds into the atmosphere to provide opportunities for BTX biodegradation. Oxygen-free anoxic and microaerobic (< 0.2 mg/L dissolved oxygen) conditions were established using a novel laboratory reactor configuration. ORP was successfully used to monitor different electron acceptor conditions in the SBR. Toluene and m-xylene were amenable to anoxic (denitrifying) metabolism while benzene, o-, and p-xylene were biodegradable under microaerobic conditions. The results demonstrate that establishing microaerobic conditions in full-scale bioreactors may be an appropriate way to encourage the biodegradation of aerobically biodegradable volatile contaminants. Additionally, the laboratory reactor configuration introduced in this paper may be useful in subsequent studies involving microaerobic metabolism.

Aerobiosis↗
PubMed1996

A system and methodology for measuring volatile organic compounds produced by hydroponic lettuce in a controlled environment.

A system and methodology were developed for the nondestructive qualitative and quantitative analysis of volatile emissions from hydroponically grown 'Waldmann's Green' leaf lettuce (Lactuca sativa L.). Photosynthetic photon flux (PPF), photoperiod, and temperature were automatically controlled and monitored in a growth chamber modified for the collection of plant volatiles. The lipoxygenase pathway products (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate were emitted by lettuce plants after the transition from the light period to the dark period. The volatile collection system developed in this study enabled measurements of volatiles emitted by intact plants, from planting to harvest, under controlled environmental conditions.

Air↗
PubMed1986

Sulfur isotope effects associated with protonation of HS- and volatilization of H2S.

The isotope effects associated with: (1) formation of H2S from HS- by protonation in aqueous solution; and (2) volatilization of H2S have been experimentally determined. Both isotopic distributions in closed systems at equilibrium and differential rates of volatilization of isotopic species in open systems were measured at 22 +/- 1 degrees C. It was found that, at equilibrium aqueous H2S is enriched in 34S by 2.0 - 2.7% relative to HS- and that H2S volatilized from solution is depleted in 34S by 0.5% relative to dissolved H2S. A small kinetic isotope effect accompanying volatilization of H2S was observed in the open-system experiments.

Geological Phenomena↗
PubMed1998

[Effect of turmeric volatile oil on the respiratory tract].

OBJECTIVE: Researching the effect of turmeric volatile oil on functions of the respiratory tract. METHOD: The action of turmeric volatile oil on sputum removing, cough and asthma relieving was observed by vapour inhaling. RESULT: The volatile oil is significantly active in removing sputum, relieving cough and preventing asthma. CONCLUSION: Turmeric volatile oil may be an efficacious drug for the treatment of respiratory diseases.

Animals↗