Odors research

Engen, T. (1972). The Effect of Expectation on Judgements of Odor. [Research Report ICRL-RR-70-11.] Washington, DC Injury Control Research Laboratory, US Department of Health, Education and Welfare. 

The structure/activity relationship (SAR) tools employed in odor research are essentially the same standard tools used in all applications, and the models developed fall into the categories of substrate and receptor models. The pharmaceutical industry is the leader in SAR techniques, and the fragrance industry tends to follow its lead. Early models were substrate based, but the discovery of the genes that code for the olfactory receptor proteins has also allowed receptor models to be constructed. 

Weurman, C. (1969) Isolation and concentration of volatiles in food odor research... 

Essential is also used as the adjective form of the noun essence The mixtures of substances that make up the fragrant material of plants are called essential oils because they contain the essence that is the odor of the plant The study of the composition of essential oils ranks as one of the oldest areas of organic chemical research Very often the principal volatile component of an essential oil belongs to a class of chemical sub stances called the terpenes... 

The odor detection-threshold values of organic compounds, water, and mineral oil have been determined by different investigators (Table 2 and 3) and may vary by as much as 1000, depending on the test methods, because human senses are not invariable in their sensitivity. Human senses are subject to adaption, ie, reduced sensitivity after prolonged response to a stimulus, and habituation, ie, reduced attention to monotonous stimulation. The values give approximate magnitudes and are significant when the same techiriques for evaluation are used. Since 1952, the chemistry of odorous materials has been the subject of intense research (43). Many new compounds have been identified in natural products (37—40,42,44—50) and find use in flavors. 

Researchers at the MoneU Center (Philadelphia, Pennsylvania) are using a variety of electrophysical and biochemical techniques to characterize the ionic currents produced in taste and olfactory receptor cells by chemical stimuli. These studies are concerned with the identification and pharmacology of the active ion channels and mode of production. One of the techniques employed by the MoneU researchers is that of "patch clamp." This method aUows for the study of the electrical properties of smaU patches of the ceU membrane. The program at MoneU has determined that odors stimulate intraceUular enzymes to produce cycUc adenosine 3, 5 -monophosphate (cAMP). This production of cAMP promotes opening of the ion channel, aUowing cations to enter and excite the ceU. MoneU s future studies wiU focus on the connection of cAMP, and the production of the electrical response to the brain. The patch clamp technique also may be a method to study the specificity of receptor ceUs to different odors, as weU as the adaptation to prolonged stimulation (3). 

The future in research will certainly lead to a better understanding of how odors are recognized, sorted, and classified. Studies promise, among other things, to determine whether perceptually similar, but stmcturaHy different, odors share the same class of receptor proteins, whether responses to odors can be modified, and possibly why olfactory neurons regenerate but other neurons do not. 

Synthesis. Exploratory research has produced a wide variety of odorants based on natural stmctures, chemicals analogous to naturals, and synthetic materials derived from available raw materials and economical processing. As in most areas of the chemical industry, the search for new and useful substances is made difficult by the many materials that have been patented and successfully commercialized (4). In the search for new aroma chemicals, many new materials are prepared for screening each year. Chemists who perform this work are involved in a creative exercise that takes its direction from the commercial sector in terms of desirable odor types and specific performance needs. Because of economic limitations, considerations of raw material costs and available processing methods may play a role eady in the exploratory work. 

National Research Council, "Odors from Stationary and Mobile Sources." National Academy of Sciences, Washington, DC, 1979. 

The cross-dimerization reaction is very commonly employed for the manufacture of intermediates for synthetic musks, which have become an important class of perfumery chemicals. Synthetic musks have been the target of extensive research over the years due to a conservation order placed on the musk deer. Nitro musks are being steadily replaced by non-nitro polycyclic musks becau.se of technical drawbacks and health aspects of the former, which are explosive, sensitive, and virtually nonbiodegradable. Non-nitro musks, on the other hand exhibit better stability to light and alkali, and more nearly duplicate the odour of the macrocyclic musks occurring in nature. Indian musk odorants are easily soluble in alcohol and perfume compositions. They have the added advantage of non-discoloration in soap and domestic products. In view of the low price, their future in the perfume industry appears very promising. 

L. L. Altpeter, Jr. Research recommended to develop odorant-fade model. Pipe Line Gas Ind, 80(2) 39 0, February 1997. 

As the chemical industry expanded, Perkin continued his own scientific research in the peace of his private laboratory. He had not lost his touch. Among the synthetic methods he discovered is one now called the Perkin reaction. He used it to make a synthetic substitute for a vegetable substance called coumarin, which has a pleasant, vanillalike odor. Coumarin spawned the synthetic perfume business and made luxurious scents available to all. Once again, a Perkin chemical started a new industry, albeit a modest one in comparison with dyes and pharmaceuticals. Despite the worldwide impact of Perkins discoveries, he was not knighted by the British monarchy until 1906, the fiftieth anniversary of his discovery of mauve. The world chemistry community feted him lavishly that year, and he traveled to the United States collecting further honors. A year later, at the age of 69, he died peacefully, at home. 

Carotenoids are one of the most abundant groups of pigments found in nature. Every year more than 100 million tonnes of them are being synthesized in the biosphere. Nearly 600 molecular species of carotenoids are currently identified (Del Campo et al., 2007). As powerful antioxidants, vitamin precursors, natural colorants, and odorants they became a serious global market commodity accounting for almost 1 billion dollars of the yearly trade (BCC research, 2007). 

Most often consideration is given only to keeping odors from reaching other parts of the building. From a health and safety perspective, this is the last of many reasons for the use of a separate ventilation system. In some research applications the animals in use or the diseases under study are zoonotic (animal diseases transferable to humans). Under these conditions special precautions must be taken to prevent exposure to humans. For example, sheep carry a zoonotic disease called Q Fever which is... 

TABLE 4.5. Odor and Human Health-Related Effects of Hydrogen Sulfide in the Atmosphere (U.S. National Research Council, 1979 ASCE, 1989). 

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