Odor modification

See Carboxylic acids Desiccants Driers and metallic soaps. 

Although the nose houses and protects the cells that perceive odor, it does not direcdy participate in odor perception. The primary function of the nose is to direct a stream of air into the respiratory passages. While this function is occurring, a small fraction of the inhaled air passes over the olfactory epithelium, located 5—8 cm inside the nasal passages. This olfactory area occupies about 6.45 cm (one square inch) of surface in each side of the nose. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

The vomeronasal organ (VNO), located in the nose, is a small chemical sensing stmcture associated with odors and behavioral effects. The vomeronasal system, which is made up of the VNO and a portion of the brain s limbic system, is stmcturaHy independent of the olfactory and nervous terminalis systems in the nose. It may, however, interact with these systems in a manner dependent on prior experience or learning, and therefore be direcdy related to the association of smells and experiences. This independent chemosensory system in the nose may prove to open doors to new learning associated with the sense of smell and human behavior. 

According to the chemical theory of olfaction, the mechanism by which olfaction occurs is the emittance of particles by the odorous substances. These particles are conveyed to the olfactory epithelium by convection, diffusion, or both, and dkecdy or indkectly induce chemical changes in the olfactory receptors. 

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Odor masking Odor modification Odor perception Odor removal... 

PermeOx is also used to improve the bioremediation of soils contaminated with creosote or kerosene, to deodonze sewage sludges and wastewater, and to dechlonnate wastewater and effluents. See also Odor Modification. 

Yvette Berry. Reckitt A Caiman Inc.. Wtnite. NJ. bttp //www. rcckitt.com/. Odor Modification... 

The model developed, which has been in use for many years both for the training of professionals and specialists and the preliminary education of nonspecialists, leads toward a universal language for odor relationships, and is named the spectrum or field of odor. This spatial model has been based on 42 reference odorants, including vanillin., and is becoming the methodological reference for describing odors (see Odor modification). 

Another modification of this process was reported in 1988 (84). In this process, a precondensate of THPC and urea, plus excess urea, are neutralized to a pH of about 5.7, and the buffer salt is added. The fabric is then given a standard pad-dry-cure process followed by oxidation and laundering. The principal advantage of this modification is a reduction in both formaldehyde vapors and phosphine-like odors released during processing (84). 

Panehsts are trained to evaluate malodor intensity and the degree of modification. It is important that the paneflst be able to smell through any extraneous odor(s), such as the fragrance of the product, to evaluate the efficacy of products making elimination or neutralization claims, as opposed to the phenomenon of masking. 

Specific scales may be used to rate the perception of intensity of (/) the malodor, and (2) the malodor along with an odorous material designed to modify the malodor. Rating scales may consist of numerical assignments to words, eg, from 0 = no odor to 10 = very strong odor. These same type of scales maybe used to describe both the hedonic acceptabiUty of the net result, ie, from 0 = very unpleasant to 10 = extremely pleasant, and the degree of modification, ie, from 0 = does not modify to 10 = complete elimination or cover-up. 

Attempts have also been made to reduce the odor associated with the peracid in the home laundry. Use of a precursor that generates the peracid of a fatty acid can result in an objectionable odor in the wash bath (106). This odor is exacerbated by the higher piC of the peracid versus its parent acid resulting in a greater proportion of the peracid in the unionized and therefore less water-soluble form. To mitigate this circumstance, functionalization of the fatty tail typically alpha to the carbonyl has been utilized (112). The modifications include alpha-chloro and alpha-methoxy substituents on the parent acid portion of the precursor ester. 

Because the quality and health aspects of foods cannot be measured by a single index, it necessarily follows that the subject of control methods in the canned food industry is very broad, and includes chemical, physical, organoleptic, and bacteriological tests, only the first of which is discussed here. The measurement of color, odor, optical clarity, texture, viscosity, and chemical composition has been used to evaluate canned foods, but in many cases the methods that are applicable to one product are either not applicable to another, or can be used only after considerable modification. 

The odor of ambergris, urine, sandalwood, and musk are believed to be related to their distinct structures, and small structural modifications can influence decisively the odor quality and potency. There are three different classes of musk that are not related in structure ... 

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