Odoriferous properties

Essential oils are highly concentrated substances extracted from flowers, leaves, stems, roots, seeds, barks, resins, or fruit rinds. The levels of essential oils found in plants can be anywhere from 0.01% to 10% of the total. This is why tons of plant materials are required for just a few hundred pounds of oil. These oils are often used for their flavor and their therapeutic or odoriferous properties, in a wide selection of products such as foods, medicines, and cosmetics. 

The oxidative degradation of carotenoids (Figure 7.3), terpenes with 40 carbon atoms (tetrater-penes), produces derivatives with 9, 10, 11 or 13 carbon atoms (Enzel, 1985). Among these compounds, norisoprenoid derivatives with 13 carbon atoms (Ci3-norisoprenoids) have interesting odoriferous properties. These compounds are common in tobacco, where they were initially smdied (Demole et al., 1970 Demole and Berthet, 1972), but they have also been studied in grapes (Schreier et al., 1976 Simpson et al., 1977 Simpson, 1978 Sefton et al., 1989 Winterhalter, 1993). 

Attention has already been drawn to the desirable odoriferous properties of alkylidenephthalides (13/14) and bovolide (15) and their analogues (p. 136>.. In one isolated report the synthetic ethylidenebuten-olide (226) has been reported to possess carcinogenic properties 200). 

Four ethers of the bisabolane series have so far been found in nature. The sole member of this series whose odoriferous properties... 

It seems evident therefore that the unsatisfied affinity of an odoriferous body plays a fundamental part in the production of its odour by reason of one or more chemical reactions taking place in the olfactory organ the reactions must necessarily be complicated and rapid. They are at present entirely unknown and problematical, but no very great progress in the knowledge of this subject is likely to be made until the chemical properties of the osmoceptors have been determined. 

Physical Properties Sulfur mustard (mustard gas) is a colorless oil with bp of 227°C, mp of 14°C, molecular dipole moment 1.78 D (hexane), and molecular mass of 159. It normally is encountered as an impure, pale yellow-brown, odoriferous liquid. The color generally deepens with increasing amounts of impurity. HD has a vapor density of 5.4 relative to air and a vapor pressure of 0.072 mm Hg at 20°C. As a liquid, it is slightly denser than water (1.27 g/mL at 20°C). It is miscible in typical organic solvents (e.g., carbon tetrachloride, acetone or chloroform) but has a lower solubility in water (0.092 g/100 g at 22°C) (Sidell et al., 1998 Somani, 1992). 

Furenidones are similar to y-pyrones in certain of their chemical properties. IsomaUol has already been mentioned, and it is the odoriferous material found in bread. Hodge and co-workers recently elucidated its structure. Its properties indicate that it has an enolic character without doubt (pAn o 5 60 purple color in the ferric chloride reaction 0-methylation by CH2N2 stable to alkali labile to acid UV, IR, NMR measurements ). Isomaltol is therefore a genuine 3-hydroxyfuran, as is 3,4-dihydroxyfuran-2,5-dicarboxylic ester, which has been known for a long time. 

The herb Cleome viscosa (syn. cleome icosandra)y which is widely distributed in India, has long been recognized by the native population to serve as a rubefaciant, vesicant, and anthelmintic agent. As a consequence of these reputed properties, three research groups undertook almost simultaneously in the late 1970 s to determine the principal active constituent of this sticky, odoriferous plant [82,83]. On the basis of the NMR, X-ray, and CD data, the substance was determined to be the macrocyclic diterpene lactone 160 and named cleomeolide. The structural features of this macrolide are unusual in several respects (a) the double bond positioned a,p to the lactone carbonyl resides at a bridgehead site, a... 

Jasmonic acid was first discovered as its methylester (2) an odoriferous compound from the essential oil of jasmine (Jasminum grandiflomm L.) [3], Early interest in this compound centered on its fragrant properties but recently, jasmonic acid and its methyl ester have fascinated plant physiologists and molecular biologists because they have been shown to possess hormonal activity [4], can act as a senescence-promoting substance [5], and can induce JIP (jasmonate induced proteins) [6] and soybean vegetative storage proteins [7],... 

Molecular properties, whose variations can be attributed to variations in molecular sh, include odor, taste, optical dichroism (the octant rule ), chirality, and drug-receptor interaction. In 1920 RuiiCka forwarded a theory that the character of an odoriferous substance is determined by its molecular shape, while the variations of this character depend on the osmophoric groups in a molecule. This presented but one illustration of Emil Fisher s lock and key model for interaction of drugs and enzymes. ... 

One of hydrogen sulfide s most readily recognized properties is its odor, which is most frequently encountered as the offensive odor of rotten e s. Hydrogen sulfide is toxic but our noses can detect H2S in extremely low, nontoxic concentrations. A sulfur-containing organic molecule, such as dimethyl sulfide, (CH3)2S, which is similarly odoriferous and can be detected by smell at a level of one part per trillion, is added to natural gas as a safety factor to give it a detectable odor. 

Commercial amyl formate is an anhydrous, colorless liquid composed of a mixture of isomeric amyl formates with the isoamyl formate in predominance. This mixture is miscible with oils, hydrocarbons, alcohols, ketones and so forth. It is a solvent for cellulose esters, "Cumar , copal, gum esters, etc. It is able, when mixed with an alcohol, to dissolve shelloc and alkyd resin. It Is a less odoriferous and mare energetic solvent than amyl acetate. It also has bath a lower boiling point and a greater speed of evaporation. n-Butyl acetate and amyl formate have similar volatility and have substantially the same solvent power which permit free interchange of these only as far as these properties allow. 

Definition Aq. sol n. of the odoriferous principles of the flowers of the orange. Citrus aurantium var. dulcis] constituents are limonene, l-linalool, geraniol, linalyl acetate (7-18%), some methyl anthranilate, nerol, neroli camphor Properties YIsh. fluorescent liq. turns brown on exposure to light very intense, pleasant odor sol. in DMSO, 95% ethanol, acetone sol. < 1 mg/ml in water sp.gr. 0.86-0.88 flash pt. > 93.3 C ref. index 1.475 (20 C) pH neutral or si. acid to litmus volatile... 

If I was to attempt to write of all the species of animals, it would be a long and tedious task. I believe certainly that our Pliny did not touch upon a thousandth part of the animals and birds that exist in this region nor could an artist such as Policletus, succeed in painting them. All the trees are odoriferous, and some of them emit gums, oils, or other liquors. If they were our property, I do not doubt but that they would be useful to man. If the terrestrial paradise is in some part of this land, it cannot be very far from the coast we visited. It is, as I have told you, in a climate where the air is temperate at noon, being neither cold in winter nor hot in summer. 

Cyclodextrins form crystalline inclusion complexes with many organic compounds, including some gases, which are bound within the molecule. Formation of these complexes is called encapsulation. Encapsulation results in a change of the physico-chemical properties of encapsulated compounds (e.g. volatility of flavour-active compounds and their increased stability against oxidation and photodegradation). Cyclodextrins are, therefore, of greatest use as carriers (encapsulators) of odoriferous substances, emulsion stabilisers and are also used to remove bitter substances from citrus juices (see Section 8.3.5.1.1). 

Characteristic organoleptic properties of odoriferous substances are related to their structure and their stereochemistry. Small changes in the structure of molecules often lead to drastic changes in the quality and quantity of sensory perception. Structural analogues of compounds or structural isomers (positional isomers as well as functional isomers) therefore often exhibit different organoleptic properties. Odour-active substances are mostly chiral molecules, and the individual enantiomers or diastereoisomers have different organoleptic properties. Smell is a phenomenon associated with the elementary composition of substances, their spatial arrangement... 

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