Odor optimization

The information gained by application of odor evaluation and odor analysis of indoor environment and material samples not only serves the purpose of knowledge accumulation, but can also be used as a tool for air quality and product improvement. The combination of the two methods has the potential of a systematic approach to developing odor optimized technical materials. One example is given here. 

Most aroma chemicals are relatively high boiling (80—160°C at 0.4 kPa = 3 mm Hg) Hquids and therefore are subject to purification by vacuum distillation. Because small amounts of decomposition may lead to unacceptable odor contamination, thermal stabiUty of products and by-products is an issue. Important advances have been made in distillation techniques and equipment to allow routine production of 5000 kg or larger batches of various products. In order to make optimal use of equipment and to standardize conditions for distillations and reactions, computer control has been instituted. This is particulady well suited to the multipurpose batch operations encountered in most aroma chemical plants. In some instances, on-line analytical capabihty is being developed to work in conjunction with computer controls. 

Because PEA is such an important fragrance material this simple, essentially one-step process has been exhaustively studied to optimize reaction conditions and purification procedures. Because of the high reactivity of the iatermediates and the tendency toward polymer formation, critical factors such as throughput, temperature, molar ratios of reactants, addition rates, reactor materials and design, and agitation rate must be carefully balanced to provide an economical product with acceptable odor properties. 

Consider that the odor perception by human nose is correlated with the odor value, OVj, in the headspace above the liquid. If a specific OVt distribution values is wanted, the perfume composition can be determined with the help of Equation (2). This methodology can facilitate the optimization of perfume compositions, reducing in this way some trial and error time and chemical wastes. Clearly, the problem is determined by structural decisions because the perfume composition depends on the interaction of the different perfume components. 

The rest was routine choosing propene as a thermodynamically favorable leaving group (17, 19, 20), diallylsulfide was synthesized despite its odor and pyrolyzed with PE spectroscopic optimization (4) of the conditions ... 

Temperature and humidity is controlled to minimize evaporation of reagents and to keep performance of electronic equipment optimal. Ventilation is adequate for the removal of noxious fumes and odors. Formaldehyde and xylene vapor concentrations must be below maximum permissible levels. For formaldehyde, this level is 0.75 ppm for an 8-h time-weighted average, or 2.0 ppm for a 15-min short-term exposure. For xylene, the level is 100 ppm for an 8-h time-weighted average and 200 ppm for a 15-min short-term exposure. The monitoring of the work area and employees can be performed on a yearly basis. Chemical and biological safety cabinets are checked for proper airflow on a yearly basis. 

R.J. Harper, J.R. AhniraU and K.G. Furton, Identification of dominant odor chemicals emanating from explosives for use in developing optimal training aid combinations and mimics for canine detection , Talanta 67 (2005) 313—327. 

Land animals exploit the odorsphere, the world of vapors around them. In any given locale, they move in an odorscape, a landscape of volatiles. Even in fish we speak of odors because neurophysiologically the olfactory system is involved, even though water-soluble stimulants are not necessarily volatile. We expect vertebrates to have taken advantage evolutionarily of the physicochemical characteristics of their environment first to select and then to optimize chemical communication. The chemical communication system of a cold-water fish differs vastly from that of a tropical bat. Despite similar biological functions, each system has been shaped by, and is adapted to, a distinct set of environmental circumstances. 

Hayes, A. T., A. Martinoli, and R. M. Goodman. Swarm robotic odor localization Off-line optimization and validation with real robots, Robotica 21, 427-441 (2003). 

Pyridine was used in the beginning of the development of the method. The reaction was slow and the endpoint unstable because of weak basicity of pyridine. The pyridine system buffers at about pH 4. A stronger base, imidazole, has been used to replace pyridine since it gives a faster response and has the advantages of lower toxicity and decreased odor. The optimal pH range for the SO2 imidazole buffer is at pH 6. It is important that the pH of the Karl Fisher reaction be maintained within the range 5 to 7. Outside this recommended pH range, the endpoint may not be reached. 

Lecanu, L., Ducrest, V., Jouquand, C., Gratadoux, J. J., and Feigenbaum, A. (2002). Optimization of headspace solid-phase microextraction (SPME) for the odor analysis of surface ripened cheese. ]. Agric. Food Chem. 50, 3810-3817. 

Application of the Combination of Odor Evaluation and Odor Analysis for Product Optimization... 

Benanou, D., F. Acobas, and M.R. De Roubin. 2004. Optimization of stir bar sorptive extraction applied to the determination of odorous compounds in drinking water. Water Sci. Technol. 49 161-170. 

Binding of hydrophobic molecules by specific protein carriers appears to be a very efficient mechanism to increase both solubility and transport of these molecular messengers in a hydrophilic medium. OBPs and CSPs may represent a successful application of this principle. In particular, the molecular mechanisms of transport of hydrophobic molecules may be more ancient than that most ancient of senses, olfaction. The olfactory system may have developed to extract the hydrophobic odorants from the air environment and optimize their transport and delivery to sensory cells. 

In order to evaluate the best temperature and time of baking process, Silva et al. (2008) used an expert panel to analyze seven descriptors, including dried fruit, nutty, baked, oak, mushroom, and brown sugar. The optimal temperature and time of baking process respecting the specificity of Madeira winemaking are considered 45 °C for 4 months. On the basis of aroma extract dilution analysis (AEDA), several Maillard byproducts, such as Sotolon, 2-furfural, 5-methyl-2-furfural, 5-ethoxy-methyl-2-furfural, methional, and phenylacetaldehyde, were identified in both Malvasia and Sercial wines under study which may explain the baked, brown sugar, and nutty odor descriptors. 

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