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At least 343 records · Page 19Linked to original sources
PubMed2006

Bias of Tedlar bags in the measurement of agricultural odorants.

Odor regulations typically specify the use of dynamic dilution olfactometery (DDO) as a method to quantify odor emissions, and Tedlar bags are the preferred holding container for grab samples. This study was conducted to determine if Tedlar bags affect the integrity of sampled air from animal operations. Air samples were collected simultaneously in both Tedlar bags and Tenax thermal desorption tubes. Sample sources originated from either a hydrocarbon-free air tank, dynamic headspace chamber (DHC), or swine-production facility, and were analyzed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O). Several background contaminants were identified from Tedlar bags, which included the odorous compounds N,N-dimethyl acetamide (DMAC), acetic acid, and phenol. Samples from the DHC demonstrated that recovery of malodor compounds was dependent on residence time in the Tedlar bag with longer residence time leading to lower recovery. After 24 h of storage, recovery of C3-C6 volatile fatty acids (VFA) averaged 64%, 4-methylphenol and 4-ethylphenol averaged 10%, and indole and 3-methylindole were below the detection limits of GC-MS-O. The odor activity value (OAV) of grab samples collected in Tedlar bags were 33 to 65% lower following 24 h of storage. These results indicate that significant odorant bias occurs when using Tedlar bags for the sampling of odors from animal production facilities.

Air Pollutants↗
PubMed2007

Evaluation of zeolite for control of odorants emissions from simulated poultry manure storage.

Poultry operations are associated with emissions of aerial ammonia (NH3), volatile organic compounds (VOCs), and odor, and the magnitude of emissions is influenced by manure management practices. As a manure treatment additive, zeolites have been shown to have the potential to control NH3. Because of their properties it is also expected that zeolites could effectively adsorb VOCs and odor. The effectiveness of zeolite in controlling odor and VOCs was qualitatively evaluated in this controlled laboratory study involving simulated poultry manure storage. In the first two trials, zeolite was topically applied on nearly fresh laying hen manure at the rates of 0, 2.5, 5, and 10% (by weight). In the third trial, zeolite was topically applied at 5% with each addition of fresh manure into the storage vessel. Headspace samples from the emission vessels were collected with solid phase microextraction (SPME) and analyzed on a multidimensional-gas chromatograph-mass spectrometry-olfactometry (MDGC-MS-O) system for identification and prioritization of poultry manure odorants. Acetic acid, butanoic acid, isovaleric acid, indole, and skatole were consistently controlled in the headspace, with the reduction rate being proportional to the zeolite application rate. Dimethyl trisulfide and phenol were consistently generated, and with a few exceptions, the rate of generation was proportional to the application rate. Average reduction of the odor caused by all odorants evaluated with SPME-GC-O was 67% (+/-12%) and 51% (+/-26%) for the two topical applications, respectively, while no significant reduction of VOCs and odor was detected for the layered application.

Animals↗
PubMed2006

Combinatorial synthesis and screening of novel odorants such as polyfunctional thiols.

Combinatorial chemistry was shown to be an efficient tool for the preparation of new aroma-impact compounds. In this case, polyfunctional thiols were synthesized quickly using halide reagents or Bunte salt intermediates. They were separated by gas chromatography and then characterized using low resolution EI and CI mass spectrometry. The individual sensorial properties of the thiol products (i.e. odor and perception threshold) were determined by GC-O (olfactometry) which uses the human nose as detector. The thiols were characterized based on their particular odors. 3-Methyl-2-buten-1-thiol, a relevant flavor naturally present in beer and coffee, emerged as the most powerful of the thiol library.

Butanes↗
PubMedDate not supplied

Measurement of biosolids compost odor emissions from a windrow, static pile, and biofilter.

A pilot study was conducted to compare odor emissions from a windrow process and an aerated static pile and to determine the odor reduction efficiency of a pilot two-phase biofilter for odor control of biosolids composting. Chemical compounds identified as responsible for odors from biosolids composting include ammonia, dimethyl disulfide, carbon disulfide, formic acid, acetic acid, and sulfur dioxide (or carbonyl sulfide). Aeration was found to reduce the concentration of ammonia, formic acid, and acetic acid by 72, 57, and 11%, respectively, compared with a nearby windrow, while dimethyl sulfide, carbon disulfide, and sulfur dioxide (or carbonyl sulfide) concentrations were below detection limits. Using dilution-to-threshold olfactometry, aeration followed by biofiltration was found to reduce the odor from biosolids composting by 98%. Biofiltration also altered the character of odor emissions from biosolids composting, producing a less offensive odor with an earthy character. Biofiltration was found to reduce the concentration of ammonia, dimethyl disulfide, carbon disulfide, formic acid, acetic acid, and sulfur dioxide (or carbonyl sulfide) by 99, 90, 32, 100, 34, and 100%, respectively. The concentrations of those odorants were estimated to be 3700, 110000, 26,37,5, and 1.2 times reported human detection limits before the two-phase biofilter, respectively, and 42,9600,18,0,3, and 0 times human detection limits after the biofilter, respectively.

Biodegradation, Environmental↗
PubMedDate not supplied

Olfactory function evaluated by SPECT.

Few articles on neuroimaging techniques in the study of central and peripheral olfactory pathways are present in the literature. By Single Photon Emission Computed Tomography (SPECT), cortical perfusion increment after sensorial stimulation can be evaluated objectively. In the present research, 10 healthy adults underwent SPECT by CER.TO.96 cerebral tomograph, before and after olfactory stimulation with lavender-water. A variable degree of cortical activation was detected in all patients. Gyrus rectus (+24.5%), orbito-frontal cortex (right +26.6%, left +25.6%), and superior temporal (right +9.9%, left +5.5%) cortical areas were always activated. A slight perfusion increase was present in middle temporal (right +3.2%, left +2.1%) and parieto-occipital (right +0.4%, left +2%) regions. Five patients affected by posttraumatic anosmia were also investigated: they showed a perfusion increment markedly inferior to 0.5% in every olfactory area. SPECT is a rather diffused, easily performed technique which yields objective semi-quantitative information on brain perfusion. Hence, it can be regarded as a promising contribution in the fields of smell neurophysiology, clinical olfactometry, and medicolegal queries.

Adult↗
PubMed2004

Characterization of nutty flavor in cheddar cheese.

The objectives of this study were to determine the volatile components responsible for the sensory perception of nutty flavor in Cheddar cheese. Cheddar cheeses with and without nutty flavors were selected by descriptive sensory analysis. Volatile aroma components from Cheddar cheeses with and without nutty flavors were isolated and characterized using solvent extraction with high vacuum distillation, dynamic headspace analysis, gas chromatography-olfactometry, and gas chromatography-mass spectrometry. More than 50 aroma-active compounds were detected in Cheddar cheeses. Consistent differences were observed between nutty and not nutty Cheddar cheeses. Strecker aldehydes were detected in higher amounts in Cheddar cheeses with nutty flavors compared with Cheddar cheeses without nutty flavors. Strecker aldehydes, dimethyl sulfide, and propionic acid were evaluated in young and aged Cheddar cheese models for nutty flavor by descriptive sensory analysis. Dimethyl sulfide and propionic acid did not contribute to nutty flavor in Cheddar cheese. The addition of Strecker aldehydes to young (<4 mo old) Cheddar cheese models resulted in nutty/malty flavor perceived by sensory analysis. When Strecker aldehydes were incorporated into aged (>9 mo old) Cheddar cheese models, nutty flavor perception increased. Strecker aldehydes contribute to nutty flavor in aged Cheddar cheese.

Aldehydes↗
PubMed2005

Effect of antioxidant (alpha-tocopherol and ascorbic acid) fortification on light-induced flavor of milk.

The effectiveness of added antioxidants against oxidation off-flavor development in light-exposed milk was evaluated using sensory and chemical analysis. Sensory testing for similarity showed no perceivable difference between control milk and milk with added (1) 0.05% alpha-tocopherol (TOC) and (2) 0.025% alpha-tocopherol and 0.025% ascorbic acid (TOC/ASC), but did demonstrate a perceivable difference when adding (3) 0.05% ascorbic acid (ASC) alone. Subsequently, sensory testing for difference showed a significant difference in oxidation off-flavor between light-exposed control milk and light-exposed milk with added TOC/ASC, whereas milk fortified with TOC was not different from control. Gas chromatography-olfactometry showed that more aroma-active flavor compounds were observed in light-exposed milk treated with TOC and TOC/ASC than light-exposed milk with no added antioxidants. The thiobarbituric acid reactive substances (TBARS) test verified chemically the extent of oxidation in control and antioxidant-treated milk samples. Milk that was exposed to light for 10 h showed a significantly higher TBARS value (0.92 +/- 0.09 mg/kg) than milk that was protected from light (0.59 +/- 0.184 mg/kg), or milk that was treated with TOC/ASC (0.26 +/- 0.092 mg/kg). Direct addition of low levels of antioxidants (TOC/ASC) to milk protected its flavor over 10 h of light exposed storage.

Animals↗
PubMed2006

Flavor profiles of full-fat and reduced-fat cheese and cheese fat made from aged Cheddar with the fat removed using a novel process.

Many consumers are concerned with fat intake. However, many reduced-fat foods, including reduced-fat cheese, lack robust flavors. The objectives of this study were to characterize the flavors found in full-fat cheese, cheese fat, and reduced-fat cheese made from aged Cheddar using a novel process to remove the fat (Nelson and Barbano, 2004). Two full-fat, aged cheeses (9 and 39 mo) were selected, and the fat was removed using the novel fat removal process. Full-fat cheeses, shredded and reformed full-fat cheeses, corresponding reduced-fat cheeses, and cheese fats were then analyzed using descriptive sensory and instrumental analysis followed by consumer acceptance testing. Cheeses were extracted with diethyl ether followed by isolation of volatile material by high vacuum distillation. Volatile extracts were analyzed using gas chromatography/ olfactometry with aroma extract dilution analysis. Selected compounds were quantified. The 39-mo cheese was characterized by fruity and sulfur notes, and the 9-mo-old cheese was characterized by a spicy/brothy flavor. Reduced-fat cheeses had similar flavor profiles with no difference in most sensory attributes to corresponding full-fat cheeses. Sensory profiles of the cheese fats were characterized by low intensities of the prominent flavors found in the full-fat cheeses. Instrumental analysis revealed similar trends. Consistent with sensory analysis, there were lower concentrations and log(3) flavor dilution factors for most compounds in the cheese fats compared with both the reduced- and full-fat cheeses, regardless of compound polarity. Consumers found the intensity of flavor in the reduced-fat cheese to be equal to the full-fat cheeses. This study demonstrated that when fat was removed from aged full-fat Cheddar cheese, most of the flavor and flavor compounds remained in the cheese and were not removed with the fat.

Cheese↗
PubMed2006

Major advances in testing of dairy products: milk component and dairy product attribute testing.

Milk component analysis is relatively unusual in the field of quantitative analytical chemistry because an analytical test result determines the allocation of very large amounts of money between buyers and sellers of milk. Therefore, there is high incentive to develop and refine these methods to achieve a level of analytical performance rarely demanded of most methods or laboratory staff working in analytical chemistry. In the last 25 yr, well-defined statistical methods to characterize and validate analytical method performance combined with significant improvements in both the chemical and instrumental methods have allowed achievement of improved analytical performance for payment testing. A shift from marketing commodity dairy products to the development, manufacture, and marketing of value added dairy foods for specific market segments has created a need for instrumental and sensory approaches and quantitative data to support product development and marketing. Bringing together sensory data from quantitative descriptive analysis and analytical data from gas chromatography olfactometry for identification of odor-active compounds in complex natural dairy foods has enabled the sensory scientist and analytical chemist to work together to improve the consistency and quality of dairy food flavors.

Animals↗
PubMed1996

Odorous constituents of ovine milk in relationship to diet.

The neutral volatile compounds of ovine milk from ewes fed on natural pasture, grass meadow, and on mixed grain rations were isolated by distillation under vacuum and then collected in traps that were cooled with liquid nitrogen. The distillate was extracted with dichloromethane, and the extract obtained was analyzed using high resolution gas chromatography and high resolution gas chromatography coupled to mass spectrometry. Seventy compounds were identified and quantitatively determined. The volatile compounds obtained were mainly esters, aldehydes, alcohols, ketones, nitrogen compounds, sulfur compounds, aromatic hydrocarbons, and lactones. The olfactometric indices and olfactory properties of 16 compounds were determined by gas chromatography and olfactometry. All of the substances were present in all three milk types with the exception of two sesquiterpenes, which were not detected in the milk from ewes fed the mixed grain ration. The two sesquiterpenes were absent also in ovine cheese obtained from milk from ewes fed the mixed grain ration, but the two sesquiterpenes were identified in cheese produced from milk of sheep fed on natural pasture. The presence of these constituents in the milk can be significant because of their potential role in determining milk and cheese flavor. Accordingly, cheese obtained during summer may be identified using sesquiterpenes as chemical markers of the milk used to make cheese.

Animal Feed↗
PubMed2004

[A case report on congenital anosmia].

We report 2 cases of congenital anosmia, in a 13-year-old girl and the other in a 10-year-old boy. They reported having no concept of "smell". The girl has no complications but the boy has congenital microphthalmia and is completely blind. They showed scale-out results on both T & T olfactometry and intravenous Alinamin test. Brain MRI detected hypoplasia or lack of the olfactory bulbs, tracts, and olfactory sulci in the frontal lobe of the brain in both patients. Neither had endocrinal dysfunction. In the boy, we biopsied the nasal mucosa in the olfactory cleft and found it had no olfactory epithelial cells at all. We found MRI to be the most useful imaging for diagnosing congenital olfactory disturbance.

Adolescent↗
PubMed1989

[Four cases of dysosmia with no vocal cords adduction during sniff (laryngeal dysosmia)].

The author first reported that the vocal cords adduct during sniff. This movement was observed both in normal and in anosmic subjects. In this paper four cases of dysosmia with no adduction of vocal cords during sniff was reported. The pattern of their olfactometry showed same tendencies, normal detective thresholds and inability of recognition and/or very low recognition threshold. With the observations and referenced articles, the author concluded that the vocal cord's adduction during sniff is a specific movement when the larynx concern with olfaction, and that the adductory movements is related to olfactory recognition. It was thought that the orbital cortex integrates the afferent stimulations from the larynx during sniff and olfaction from the nose. The author concluded also there exists these reported kind of dysosmia with no vocal cord adductory movement.

Adult↗
PubMed1996

[Investigation of "anosmic zones" associated with nasal allergy].

Twenty-seven nasal allergy patients suffering from olfactory disturbance were evaluated in this study. The intravenous olfaction test yielded almost normal responses in 27 cases. The standard olfactory acuity test, however, showed that the mean thresholds of detection of each odor were almost the same, while the mean thresholds of recognition of odors A and E were higher than those of the other odors. Douek has reported selective olfactory loss in patients with vasomotor rhinitis including allergic rhinitis and proposed the concept of "anosmic zones". By modifying the definition of "anosmic zones" in order to use it for the results of T & T olfactometry, we identified 8 patients who exhibited anosmic zones among 27 subjects. These results were inconsistent with the proposed mechanism that nasal obstruction causes olfactory disturbance in patients suffering from nasal allergy. Therefore, the specific factors related to nasal allergy may influence olfaction. We speculate that the pathological changes in the olfactory mucosa may induce secondary abnormalities in olfactory transduction, particularly at the point of signal transduction in olfactory cells. Other possibilities to explain anosmic zones were also discussed.

Adolescent↗
PubMed2002

Odor discrimination and odor quality perception in rats with disruption of connections between the olfactory epithelium and olfactory bulbs.

Rats were trained using olfactometry and operant conditioning to discriminate among homologous fatty acids, homologous aldehydes, and a series of unrelated odors. Their memory for the positive and negative assignment of each odor (tested under extinction) was assessed before and after they had received selective lesions of the olfactory bulbs or injection of the olfactory epithelial toxin 3-methyl indole (3-MI). Response accuracy on the memory test provided a measure of the extent to which treatments altered the remembered perceptual quality of the odors. The degree of deafferentation of the bulb by treatment with 3-MI was assessed using anterograde transport of horseradish peroxidase applied to the olfactory epithelium. Rats treated with 3-MI had a detectable reaction product only in varying numbers of glomeruli on the lateral and, in some cases, posterior medial walls of the olfactory bulb. Bulbar lesions destroyed the dorsal and dorsomedial bulbar areas that have been identified in optical and electrophysiological studies as showing responses to fatty acids. Rats with bulbar lesions had good to near perfect retention on their post-treatment memory test on all odor pairs, as did 3-MI-treated rats that still had substantial input to glomeruli on the lateral or posterior medial wall of the bulb. 3-MI-treated rats with substantially fewer afferent connections had severe retention deficits, particularly for the aldehyde and fatty acid odors, but this loss was secondary to deficits in the ability to discriminate among these odors. The results indicate that input to bulbar areas that are activated by a series of homologous odors may not be essential for odor discrimination and that deafferentation of the majority of bulbar glomeruli may be primarily without effect on odor quality perception as assessed by the memory test. These outcomes point to a much higher degree of redundancy within the olfactory bulb than that envisioned by current combinatorial or odotopic hypotheses of odor quality coding or, alternatively, to mechanisms of odor coding used in the awake behaving animal that have not yet been elucidated.

Afferent Pathways↗
PubMed2001

A pilot-scale study on biofilters for controlling animal rendering process odours.

Heating of animal tissue during the process of rendering liberates a variety of odorous compounds. The performance of biofiltration in removing these odours was investigated using pilot-scale biofilters containing different media (sand, finely and coarsely crushed wood bark, and bark/soil mixture). Odour-removal performance of the biofilters was determined using olfactometry. Biofilter odour removal efficiencies of between 29.7% and 99.9% were measured at influent odour concentrations of between 143,100 and 890,000 odour units m(-3), and various air loading rates (0.074-0.592 m(-3) air m(-3) medium min(-1)). Biofilters with bark or bark/soil media and low air loading rates gave the best odour removal. The bark and sand biofilters generally maintained good odour reduction for about three years at an air loading rate of 0.148 m(-3) air m(-3) medium min(-1). Drainage from the biofilters contained significant concentrations of nitrogenous and organic compounds, suggesting that controlled leaching has the potential to remove accumulated substances in biofilter media from rendering gas emissions and increase the longevity of a biofilter system. High pressure drop across biofilter media can adversely affect the odour removal performance. Sand and fine bark, due to their small particle size, caused high pressure drops. Coarse bark showed negligible pressure drop at several examined air loading rates. Pressure drop also increased with moisture content, particularly in sand and fine bark biofilters. Overall pressure drop characteristics of the biofilters described in this paper were maintained without significant change over the three year operation.

Abattoirs↗
PubMed2001

Sensor arrays: an inspired idea or an objective measurement of environmental odours?

The measure of annoyance odours from sewage tratment, landfill and agricultural practise has become highly significant in the control and prevention of dorous emissions from existing facilities and its crucial for new planning applications. Current methods (such as GC-MS analysis, H2S and NH3 measurements) provide an accurate description of chemical compositions or act as surrogates for odour strength, but tell us very little about the perceived effect, whereas olfactometry gives the right human response but is very subjective and expensive. The use of non-specific sensor arrays may offer an objective and on-line instrument for assessing olfactive annoyance. Results have shown that sensor array systems can discriminate between different odour sources (wastewater, livestock and landfill). The response patterns from these sources can be significantly different and that the intensity of sensor responses is proportional to the concentration of the volatiles. The correlation of the sensors responses against odour strengths have also shown that reasonable fits can be obtained for a range of odour concentrations (100-800,000 ou/m3). However, the influence of environmental fluctuations (humidity and temperature) on sensor baselines still remains an obstacle, as well as the need for periodic calibration of the sensory system and the choice of a suitable gas for different environmental odours.

Agriculture↗
PubMed2001

Comparison of different approaches used to regulate odours around the world.

A number of different countries, and states and local regulatory agencies within countries, have struggled with developing effective odour regulations or guidelines. The challenge is to develop regulations or guidelines that both avoid odour annoyance conditions and are not excessively conservative. This paper will present highlights of odour regulations or guidelines in Europe, Asia, Australia, New Zealand and North America. A comparison between the different approaches will be presented. With a number of countries reporting an increase in complaints due to odours, the field of odour assessment is rapidly evolving. Complaints due to odours from livestock facilities are also significantly increasing in many countries. A comparison of approaches used to regulate livestock operations is also included in the paper. The potential impact of European olfactometry standardisation efforts to existing assumptions about odour annoyance or nuisance levels is analysed.

Agriculture↗
PubMed2002

Assessment of olfactory status in allergic and non-allergic rhinitis patients.

A study undertaken to assess the olfactory acuity in allergic (group I) and non-allergic rhinitis (group II) patients in comparison with age and sex matched controls (group III). Patients presenting with atleast three of the five cardinal symptoms of rhinitis i.e. rhinorrhoea, sneezing, itching, headache and nasal obstruction were grouped as non-infective rhinitis and further divided into allergic rhinitis (group I, n = 20) and non-allergic rhinitis (group II, n = 20) based on nasal smear cytology positivity or negativity for eosinophils respectively. Detailed Ear, Nose and Throat examination was carried out in both the groups and peripheral blood samples were analysed for total, differential leukocyte and absolute eosinophil counts using standard techniques. In all the three groups the olfactory thresholds for 5 odorants i.e. musk (M), formalin (F), camphor (C), asafoetida (A, 10% aqueous solution) and oil of peppermint (P, 20%) were evaluated for testing musky, pungent, camphorous, putrid and minty odours respectively by the method described by Elsberg and Levy for quantitative olfactometry. The results indicated elevation of olfactory thresholds (delta %, calculated taking control values as 100%) for 4 or 5 odorants in group I and group II patients respectively as compared with controls (group I: delta % for P--89.6%; M--116.4%; A--55.8%; P < 0.001; C--73.1%; P < 0.02; F--26.6% N.S.; group II: P--96.9%; M--99.3%, P < 0.01 for both; A--66.8%; C--102.7%, P < 0.001; F--42%, P < 0.05). In the non allergic rhinitis group the magnitude of the olfactory loss was more severe except for the odorant musk. Further interpretations as per gender based specificities revealed more severe olfactory loss in males of both the groups for the odorants peppermint and musk and moderately severe olfactory loss for formalin and camphor as compared to females. However, for the odorant asafoetida females showed greater olfactory loss than males in both the groups (delta % 73.38% versus 52% in group I and 81.29% versus 69.7% in group II).

Adult↗