Volatile Aromatics Research Articles

Breast Cancer-Related Chemical Exposures in Firefighters.

To fill a research gap on firefighter exposures and breast cancer risk, and guide exposure reduction, we aimed to identify firefighter occupational exposures linked to breast cancer. We conducted a systematic search and review to identify firefighter chemical exposures and then identified the subset that was associated with breast cancer. To do this, we compared the firefighter exposures with chemicals that have been shown to increase breast cancer risk in epidemiological studies or increase mammary gland tumors in experimental toxicology studies. For each exposure, we assigned a strength of evidence for the association with firefighter occupation and for the association with breast cancer risk. We identified twelve chemicals or chemical groups that were both linked to breast cancer and were firefighter occupational exposures, including polycyclic aromatic hydrocarbons, volatile aromatics, per- and polyfluoroalkyl substances, persistent organohalogens, and halogenated organophosphate flame retardants. Many of these were found at elevated levels in firefighting environments and were statistically significantly higher in firefighters after firefighting or when compared to the general population. Common exposure sources included combustion byproducts, diesel fuel and exhaust, firefighting foams, and flame retardants. Our findings highlight breast-cancer-related chemical exposures in the firefighting profession to guide equitable worker's compensation policies and exposure reduction.

Utilization of hazelnut oil oleogels for the preparation of milk couverture type compound chocolates: Composition, properties, and sensory evaluations

AbstractThe aim of this study was to use oleogels in compound chocolates. A control sample with cocoa butter (CNT) and two compound chocolates with hazelnut oil‐sunflower wax oleogel (SWO‐CC), and polyglycerol stearate oleogel (PGSO‐CC) were prepared with the same recipe. The main properties and compositions of the samples were quite similar. While CNT sample included only 37.97% of total unsaturated fatty acids, it was 74.19 and 63.08% in the SWO‐CC and PGSO‐CC, respectively. The melting peak temperatures were 32.1, 25.4, and 23.8°C for CNT, SWO‐CC and PGSO‐CC. The samples had 11.75%, 74.25%, and 74.25% shape retention index values at 60°C. Clearly compound chocolates melted at lower temperatures, but retained their shape at higher temperatures. After 15‐day temperature fluctuation storage, no fat bloom was developed. Rheological data showed that the PGSO‐CC sample was stiffer among all, and the compound chocolates melted slowly up to 40°C, but CNT melted sharply at 38°C. Further, the PGSO‐CC sample showed a lubricating behavior. Although CNT sample included 7 volatile aromatics, SWO‐CC and PGSO‐CC samples had 17 and 14 compounds, respectively. Trained panel described the samples with 13 attributes, and most profoundly the compound chocolates had lower shape, surface gloss, coffee, bitter, cooling, hardness scores, and higher coating scores. Consumer test revealed that compound chocolates had lower appearance scores, and equal aroma scores. The flavor score and acceptability were highest for the PGSO‐CC sample. Overall, this study proved that heat stable and sensorially acceptable compound chocolates could be prepared from the oleogels.

Advances in Wine Fermentation

Fermentation is a well-known natural process that has been used by humanity for thousands of years, with the fundamental purpose of making alcoholic beverages such as wine, and also other non-alcoholic products. From a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid. The fermentation process turns grape juice (must) into wine. This is a complex chemical reaction whereby the yeast interacts with the sugars (glucose and fructose) in the must to create ethanol and carbon dioxide. Fermentation processes to produce wines are traditionally carried out with Saccharomyces cerevisiae strains, the most common and commercially available yeast, and some lactic acid bacteria. They are well-known for their fermentative behavior and technological characteristics, which allow obtaining products of uniform and standard quality. However, fermentation is influenced by other factors as well. The initial sugar content of the must and the fermentation temperature are also crucial to preserve volatile aromatics in the wine and retain fruity characters. Finally, once fermentation is completed, and most of the yeast dies, wine evolution continues until the production of the final product.

Effect of Temperature on the Hydrotreatment of Sewage Sludge-Derived Pyrolysis Oil and Behavior of Ni-Based Catalyst

The high-energy potential of wastewater sewage sludge (SS) produced in large amounts around the world makes it an attractive feedstock for fuels and energy sectors. Thermochemical valorization relying on pyrolysis of SS followed by hydrotreatment of pyrolysis oil (Py-SS) might even allow the integration of SS into existing oil refineries. In the present study, catalytic hydrotreatment of Py-SS was performed over a NiCuMo-P-SiO2 catalyst in a batch reactor at temperatures in the range of 200–390 °C. Due to sulfur presence in the feed, the increasing reaction temperature induced in situ transformation of metallic Ni into Ni3S2 in the catalyst. In contrast, the Ni3P active phase possessed remarkable stability even at the harshest reaction conditions. The oxygen content in the reaction products was decreased by 59%, while up to 52% of N and 89% of S were removed at 390 °C. The content of free fatty acids was greatly reduced by their conversion to n-alkanes, while the larger amount of volatile aromatics was generated from high molecular mass compounds. The quality of oil-derived products greatly changed at elevated temperatures, providing strong evidence of effective upgrading via decarboxy(ny)lation, hydrogenation, and hydrocracking transformations.

A preliminary investigation of anaerobically digested municipal sludge cake and contaminated soil for recycling by pyrolysis

This work has investigated the potential of pyrolysis as a recycling solution for two largely uncharacterised waste streams, anaerobically digested (AD) municipal sludge cake and brownfield soil (contaminated with oily sludge). Characterisation of emitted organic compounds from pyrolysis were captured in a solvent (acetone) scrubber and analysed by GC–MS. Both AD sludge cake and brownfield soil showed considerable promise for ‘green-er’ fuels, as a source of syngas (with CO supplementation) and volatile aromatics essential for fuel quality. However, these waste streams also generated significant amounts of additional highly toxic pollutants of varying chemistries, further emphasising the importance of using a trapping approach applicable to a broader range of chemicals. Pleasingly the acetone trap showed very good efficacy in capturing this breadth of chemistries, supporting its use as an alternative capture and preparative method, for monitoring volatile and semi-volatile organic tars.

Valorization of Capia Pepperseed Flour in Breakfast Sauce Production

The aim of this study was to valorize capia pepperseed flour. Cleaned and dried pepperseeds were first ground to its flour, and then the flour was used in the preparation of two types, vegetable (VTS) and spice type (STS), breakfast sauces. Compositional, analytical and sensory characterizations of the sauces were completed. It was shown that the sauces are good sources of oil (53.0 and 53.1%), protein (10.8 and 9.7%), total dietary fiber (18.32 and 17.81%), some essential amino acids (val, leu, iso, thr, met, phe, lys), and some minerals (P, K, Ca, and Mg), respectively. Further, the VTS and STS included 24 and 43 different volatile aromatics. A trained panel described the products with ten sensory descriptors (grassy, spicy, menthol, tomato, raw vegetable, bitterness, saltiness, oiliness, fluidity and cohesiveness). The sauces are mostly bitter, spicy, and grassy products. Consumer test indicated that both sauces had above 4.00 point of general acceptance with the 1 (min) to 5 (max) hedonic scale. Overall, pepperseed flour could be successfully used in breakfast sauce formulations to provide typical peppery aroma and bitterness together with important amounts of seed protein and fiber nutrients.

Evaluation of UV-C Irradiation Treatments on Microbial Safety, Ascorbic Acid, and Volatile Aromatics Content of Watermelon Beverage

UV-C treatment technology is proposed as a potential alternative to thermal treatments for decontamination of beverages because heat may adversely affect the nutritive value and quality. Effects of UV-C irradiation processing on microbial inactivation, ascorbic acid, and volatile aromatics of watermelon beverage were evaluated using a flow-through UV system. Selected microbial agents Escherichia coli O157:H7 and Bacillus cereus endospores were inactivated by 5.31 ± 0.01 and 6.1 ± 0.01 log CFU mL−1 at UV equivalent fluence levels of 12 and 60 mJ cm−2, respectively. At UV pasteurization equivalent exposure (40 mJ cm−2), 93% ascorbic acid was retained. No significant loss of volatile aromatic aldehydes was noticed at fluence 40 mJ cm−2. Overall, the results support the UV-C processing as an alternative to traditional thermal processing to preserve quality in conjunction with microbial safety aspects of watermelon beverage.

Evaluation of a Passive Sampling Method for Long-Term Continuous Monitoring of Volatile Organic Compounds in Urban Environments.

Environmental Protection Agency Method 325 was developed for continuous passive monitoring of volatile organic compounds (VOCs), particularly benzene, at petroleum refinery fencelines. In this work, a modified version of the method was evaluated at an Ontario near-road research station in winter to assess its suitability for urban air quality monitoring. Samples were collected at 24 hour and 14 day resolution to investigate accuracy for different exposure times. Tubes were analyzed by thermal desorption-gas chromatography-mass spectrometry, and 11 VOCs were quantified, including aromatic air toxics. The same VOCs were simultaneously monitored using traditional canister sampling for comparison, and a subset of four were also monitored using a novel miniature gas chromatograph. Good agreement (within 10%) was observed between the 14 day passive tube samples and the canister samples for benzene. However, field-calibrated uptake rates were required to correct passive tube concentrations for less volatile aromatics. Passive tube deployment and analysis is inexpensive; sampling does not require power, and accurate measurements of benzene are demonstrated here for an urban environment. The method is expected to be advantageous for the generation of long-term continuous benzene datasets suitable for epidemiological research with greater spatial coverage than is currently available using traditional monitoring techniques.

Valorization of Capia Pepperseed Flour-II: Sensory Properties and Storage Stability of the New Spreadable Pastes

The aim of this study was to characterize spreadable products based on the utilization of capia pepperseed flour. Chocolate type including liquid chocolate, and molasses type including grape molasses were evaluated. The volatile aromatics compositions, sensory descriptions, consumer preferences and storage stabilities were studied. 24 volatile compounds in chocolate type and 17 volatile compounds in molasses type were quantified. 1,2,3-propanetriol, ethyl acetate and acetic acid in chocolate type, and acetic acid and methyl acetate in molasses type were dominant in concentrations. Volatiles with aroma descriptions of fruity, ethereal, nutty, buttery, cocoa, almond, green, fatty, caramel, vegetable and similar were quantified. The panel sensorially defined both products with 17 definition terms. Significant differences for brownness, nutty, raw vegetable, bitterness, chocolate/caramel, consistency, spreadability, and refreshment were determined, and thought to be caused from the main ingredients used. Consumer hedonic scores were generally higher for chocolate type, but both need improvements. Oil separation and water activity have not changed during the storage, while some color differences and microstructural changes occurred. Furthermore, free fatty acidity and peroxide value was not increased significantly and lower than 1.8% and 2.5 meqO2/kg, respectively. Overall, these new pastes could found some market value.

Valorization of Grapefruit Seeds: Cold Press Oil Production

The aims of this study were valorization of grapefruit seeds by producing oil with cold press technique and characterization of the obtained oils. Control group and enzyme treated seeds were cold pressed in laboratory scale machine, and common physicochemical properties, fatty acid, sterol, tocopherol, flavonoid, phenolic acid, pigment, volatile aromatics compositions of the oils were determined in addition to their sensory descriptive analyses. It was shown that the oil contains linoleic acid (40%), β-sitosterol (80%) and α-tocopherol (220–320 mg/kg oil) as the major components. Naringin, hesperidin, neohesperidin, rutin as prominent flavonoids; tr-ferulic and gallic acids as dominant phenolic acids were quantified. Furthermore 26 different (d-limonene, furfural, 3-methylbutanal etc.) volatile aromatics were determined. The oils are shown to be bioactives and aromatics rich samples, but they have strong bitter and astringent taste. Hence, the oil could only be used to enrich other edible oils and foods for functional purposes, and could be utilised for cosmetic, chemical, energy and other purposes.

The influence of alkali and alkaline earth metals on char and volatile aromatics from fast pyrolysis of lignin

The effect of alkali and alkaline earth metals (AAEM) on fast pyrolysis of polysaccharides has been well documented. This paper examines the effect of AAEM on fast pyrolysis of lignin, which has not been as thoroughly investigated. Acetates of several metals were infused into organosolv cornstover lignin at a concentration of 1.0mmol AAEM cation per gram lignin followed by pyrolysis at 300–800°C.One of the most notable effects was an increase in the yield of char with alkali metals producing more char than alkaline earth metals. Char yield was correlated to the electropositivity of the infused metal cations. Alkali metals increased the overall yield of volatile aromatic compounds while alkaline earth metals had the opposite effect.The infusion of AAEMs into lignin led to an increase in methanol and a decrease in alkenyl side chains on the aromatic products. Methanol is hypothesized to result from cleavage of β-carbons from the 3‐hydroxyprop-1-enyl side chains of lignin linkages while the alkenyl side chains are hypothesized to result from cleavage of γ-carbons. Therefore, alkali metals appear to catalyze cleavage of linkages in the lignin structure.

Investigation of reactions in a fluidized bed reactor during chemical looping combustion of coal/steam with copper oxide-iron oxide-alumina oxygen carrier

This paper presents data on conversion of two different coals with a chemical looping oxygen carrier, CuO-Fe2O3-alumina, and over a range of conditions including steam and various levels of reduction of the oxygen carrier.Reactions of coal/steam/CuO-Fe2O3-alumina oxygen carrier and coal/steam/partially reduced CuO-Fe2O3-alumina oxygen carrier were investigated with Wyodak coal and Illinois #6 coal in a fluidized bed reactor. Temperature programmed reaction studies indicated that the oxygen carrier enhanced the steam gasification/combustion rates of both coals. Rates of gasification/combustion were higher with Wyodak coal (sub bituminous) than that with Illinois #6 coal (bituminous). In addition to the increase in reaction rates, the total moles of carbon that were gasified and combusted from coal/steam increased in the presence of the oxygen carrier. The reduced oxygen carrier promoted the water-gas shift reaction when reacted with synthesis gas in the presence of steam, but the reverse water gas shift reaction was observed when steam was not present. The partially reduced oxygen carrier enhanced the production of H2 from coal/steam, which was different from the observations with un-reduced oxygen carrier. Water splitting reaction to produce H2 was also observed with the reduced oxygen carrier. CuO-Fe2O3-alumina reacted with coal during the temperature ramp to 850°C even in the absence of steam due to the chemical-looping oxygen uncoupling (CLOU) reaction. Fourier transform infra-red (FTIR) analysis indicated the presence of volatile aromatics during the temperature ramp and these may have also contributed to the reactions with the oxygen carrier in the absence of steam. Increasing steam concentration had a negative effect on the CLOU reaction.

An Evaluation of Select Test Variables Potentially Affecting Acute Oil Toxicity.

In the wake of the Deepwater Horizon incident (2010) in the Gulf of Mexico, an abundance of research studies have been performed, but the methodologies used have varied making comparisons and replication difficult. In this study, acute toxicity tests with mysids and inland silversides were performed to examine the effect of different variables on test results. The toxicity test variables evaluated in this study included (1) open versus closed static test chambers, (2) natural versus artificial diluent, (3) aerated versus nonaerated test solution, and (4) low versus medium energy water-accommodated (WAF) mixing energies. The use of tests using natural or artificial diluent showed no difference in either toxicity test or analytical chemistry results. Based on median lethal concentrations (LC50) of WAFs of unweathered oil (MASS), mysid tests performed in closed chambers were approximately 41 % lower than LC50 values from open-chamber studies, possibly a result of the presence of low-molecular weight volatile aromatics (i.e., naphthalenes). This research also showed that using a medium-energy WAF (with a 20–25 % vortex) increases the number of chemical components compared with low-energy WAF, thus affecting the composition of the exposure media and increasing toxicity. The comparison of toxic units as a measure of the potential toxicity of fresh and weathered oils showed that weathered oils (e.g., Juniper, CTC) are less toxic than the unweathered MASS oil. In the event of future oil spills, these variables should be considered to ensure that data regarding the potential toxicity and environmental risk are of good quality and reproducible.

Cold pressed capia pepperseed (Capsicum Annuum L.) oils: Composition, aroma, and sensory properties

In this study, cold press‐produced capia pepperseed oil samples were characterized. Pre‐roasting and enzyme treatment against control group (no pre‐treatment) were applied to the seeds prior to cold pressing, and the oil yield, meal, and oil quality parameters were examined. The physico‐chemical parameters (refractive index, viscosity, turbidity, specific gravity, color, free acidity, peroxide and iodine values, antioxidant capacity, total phenolic content, and energy value), components composition (fatty acid, sterol, and tocopherol), thermal parameters (melting and crystallization temperatures and enthalpies), volatile aromatics composition, sensory properties (Flavor Profile Analysis), and consumer perception (hedonic test) of the oil samples were accomplished. It was found that cold pressing is low in efficiency, and oil sensory quality and consumer acceptability levels were also low. Although pre‐roasted seeds yielded a little more oil and had better sensory quality, it was determined that these oils need at least a deodorization or a physical refining for acceptable sensory quality.Practical applications: The results of this study indicated that capia pepperseeds obtained as waste during vegetable processing can be used as an alternative source for cold pressed oils and a raw material for animal feed. Moreover, these seed oils have economical impact due to their essential fatty acid (linoleic acid, 71.13%), sterol, and tocopherol content. Based on the sensory findings, full or partial refining is recommended in order to increase the sensory quality of the pepperseed oil.The capia pepperseeds pretreated by roasting and enzyme applications were extracted by a cold‐pressing technique. It was shown that both treatments caused a decrease in antioxidant capacity, total phenol content, viscosity, and turbidity but an increase in oil yield and iodine number of the oils.

Reversible adsorption and separation of volatile aromatics based on a porous Cd(ii) MOF

A series of isostructual aromatics⊂CdL2(OTs)2 (aromatics = benzene, toluene, o-xylene, m-xylene and p-xylene) supramolecular complexes were prepared based on aromatic templates. The CdL2(OTs)2 framework is stable and contains square-like hydrophobic channels. It can reversibly adsorb benzene, toluene, o-xylene, m-xylene and p-xylene in the liquid phase without the loss of its structural integrity. Furthermore, it exhibits a clear affinity for these aromatics according to the following order: xylene > toluene > benzene, and it effectively separates xylene/toluene/benzene mixtures in the liquid phase under ambient conditions. In addition, aromatics⊂CdL2(OTs)2 exhibits guest-dependent luminescence properties.

Time series analysis of CO concentrations from an Eastern Kentucky coal fire

Abstract Coal fires in natural outcrops, in abandoned and active coal mines, and in coal and coal-refuse piles are responsible for the uncontrolled emissions of gases, including CO, CO 2 , H 2 S, hydrocarbons, and volatile aromatics. Typically, measurements of gases at a mine vent are made over a short time interval, perhaps no more than 10 min, including the time for replicate measurements. Such timing provides little information on longer-term variations in emissions, although comparisons of seasonal measurements suggest such changes do occur. To address this problem, we placed temperature and CO data loggers in coal fire vents to collect time series measurements for a period of up to three weeks. For one experiment, 11 days of data at one-minute intervals indicated that the CO emissions were generally in the 400–550 ppmv range. However near daily depressions in CO concentrations occurred and in some cases fell below 50 ppmv; followed by an increase to ~ 700–800 ppmv; in turn followed by a return to the ambient conditions. Data for a separate 21-day collection period in a different vent of the same fire exhibited similar trends, albeit at a higher CO concentration. The drop in CO concentration may be associated with a meteorologically-driven inhalation cycle of the fire, whereby air diluted the combustion generated CO. We propose this was followed by an increase in the intensity of the fire due to increased O 2 from the inhaled air, producing increased CO concentrations, before settling back to the ambient conditions.

Aromatic Production from Catalytic Fast Pyrolysis of Biomass-Derived Feedstocks

The conversion of biomass compounds to aromatics by thermal decomposition in the presence of catalysts was investigated using a pyroprobe analytical pyrolyzer. The first step in this process is the thermal decomposition of the biomass to smaller oxygenates that then enter the catalysts pores where they are converted to CO, CO2, water, coke and volatile aromatics. The desired reaction is the conversion of biomass into aromatics, CO2 and water with the undesired products being coke and water. Both the reaction conditions and catalyst properties are critical in maximizing the desired product selectivity. High heating rates and high catalyst to feed ratio favor aromatic production over coke formation. Aromatics with carbon yields in excess of 30 molar carbon% were obtained from glucose, xylitol, cellobiose, and cellulose with ZSM-5 (Si/Al = 60) at the optimal reactor conditions. The aromatic yield for all the products was similar suggesting that all of these biomass-derived oxygenates go through a common intermediate. At lower catalyst to feed ratios volatile oxygenates are formed including furan type compounds, acetic acid and hydroxyacetaldehyde. The product selectivity is dependent on both the size of the catalyst pores and the nature of the active sites. Five catalysts were tested including ZSM-5, silicalite, beta, Y-zeolite and silica–alumina. ZSM-5 had the highest aromatic yields (30% carbon yield) and the least amount of coke.

Continuous Cloud Point Extraction of Volatile Organic Contaminants from Wastewater in a Multi-Stage Rotating Disc Contactor: Effect of Structure and Concentration of Solutes

Cloud point extraction (CPE) has been successfully scaled up to continuously remove aromatic contaminants from wastewater in a multi-stage rotating disc contactor (RDC) using t-octylphenolpolyethoxylate. The extraction performances for the removal of organic solutes with different structures and degrees of hydrophobicity were compared here for both batch and continuous CPE. Included are the volatile aromatics benzene, toluene, and ethylbenzene; volatile chlorinated compounds dichloroethane, trichloroethylene, and tetrachloroethylene; and non-volatile phenolics phenol, o-cresol, and catechol. The higher the Kow (octanol-water partition coefficient) or hydrophobicity of the solutes, the better the extraction due to the greater affinity of solutes to solubilize into micelles. The empirical linear correlations between log Kow, log (solute partition ratio), and log (height of transfer unit or HTU) were developed. Toluene is used as a model solute for the study of effect of initial solute concentrations in the continuous RDC. The extraction ability decreases as the concentration of toluene in the wastewater increases mainly due to coacervate entrainment into the overhead effluent.

Pilot-Scale Pyrolysis of Scrap Tires in a Continuous Rotary Kiln Reactor

The pilot-scale pyrolysis of scrap tires in a continuous rotary kiln reactor was investigated at temperatures between 450 and 650 °C. As the reactor temperature increased, the char yield remained constant with a mean of 39.8 wt %. The oil yield reached a maximum value of 45.1 wt % at 500 °C. The pyrolytic derived oils can be used as liquid fuels because of their high heating value (40−42 MJ/kg), excellent viscosity (1.6−3.7 cS), and reasonable sulfur content (0.97−1.54 wt %). The true-boiling-point distillation test showed that there was a 39.2−42.3 wt % light naphtha fraction in the pyrolytic oil. The volatile aromatics were quantified in the naphtha fraction using gas chromatography−mass spectrometry. The maximum concentrations of benzene, toluene, xylene, styrene, and limonene in the oil were 2.09 wt %, 7.24 wt %, 2.13 wt %, and 5.44 wt %, respectively. The abundant presence of aromatic groups was also confirmed by functional group Fourier transform infrared analysis. The concentration of polycyclic ar...

Electron-beam treatment of aromatic hydrocarbons that can be air-stripped from contaminated groundwater. 2. Gas-phase studies.

The electron-beam (EB) degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes: BTEX) in groundwater strip gas, which in the present work has been modeled by the introduction of the desired aromatic(s) to a stream of air or another gas, such as oxygen, is initiated essentially by the addition of *OH radicals to the aromatic ring, giving rise to hydroxycyclohexadienyl radicals, which form the corresponding peroxyl radicals upon addition of oxygen. As studied in some detail with benzene as a BTEX representative, various reactions of these lead to numerous oxidation products in a cascade of reactions, including the decomposition of products under the prevailing conditions of high turnover of the initial aromatic. Importantly, hydroxycyclohexadienylperoxyl radical formation is partly reversible, and the reactions of the hydroxycyclohexadienyl radicals, which thus have a significant presence in these systems, must therefore also be taken into consideration. In the gas phase, in contrast to the aqueous phase (see Part 1), the reactions of the hydroxycyclohexadienyl radicals lead to oligomeric products that appear to contribute, in addition to ionic clusters, to nucleation for the aerosols observed. Various nitrated products, among them nitrophenols, are observed when air is used for the stripping. However, these studies did not clear the pilot plant stage, since BTEX degradation using a bioreactor carried out in parallel was so successful that the EB technology was judged to be noncompetitive. As for the latter, expensive equipment consisting of a stripper, the EB machine, and an aerosol precipitator would be required. The condensed aerosols are biorefractory and would require further treatment for detoxification.