Odoriferous compounds

The actual genesis of the odoriferous compounds in the living plant has been studied, as indicated above, principally by Charabot and his colleagues, Laloue and Hebert, but interesting work in the same direction has been carried out by Blonde and by Mesnard. 

For epidemic prevention and public health, rendering plants are bound by law to accept all perished animals and parts of animals in any stage of decomposition. Due to the nature of this raw material, containing fat and protein, its biological decomposition increases with time and temperature of storage, and very odoriferous compounds are produced. 

As storing temperature and time outside the plant are often out of the influence of the plant management, at least in summertime the handling of this veiy odoriferous material is a normal procedure. In order to prevent an escape of the odoriferous compounds into the atmosphere, in modem plants all devices and all machinery are capsulated as close as possible and all odoriferous gases and all polluted air are collected and exhausted into an appropriate air cleaning system, where all odoriferous compounds should be removed and/or desintegrated to odourless substances, before the cleaned air is released into the open atmosphere. 

Besides steroids, axillary odor also contains normal, branched, unsaturated aliphatic acids with 6 to 11 carbon members. Most abundant is (E)-3-methyl-2-hexenoic acid. Both this compound and its (Z)-isomer are found in the aqueous phase hydrolysate and the aqueous phase incubated with bacteria. It is assumed that precursors are water soluble and converted to odoriferous compounds by the axillary flora (Zeng etal., 1992). 

DC042 Kulesza, ]., ]. Kula, and W. Kwiat-kowski. Oil of carrot seed as the source of the carotol for the synthesis of the new odoriferous compounds. An Acad Brasil Cienc 1972 448 412. 

The number of synthetically produced fragrance and flavor chemicals has since expanded continually as a result of the systematic investigation of essential oils and fragrance complexes for odoriferous compounds. Initially, only major components were isolated from natural products their structure was then elucidated and processes were developed for their isolation or synthesis. With the development of modern analytical techniques, however, it became possible to isolate and identify... 

When an odoriferous compound, or odor-ivector, arrives at the olfactory organ, a reaction takes place between the odor molecules and the chemoreceptors this reaction pro-... 

The presence of 2-methy-3-furanthiol (II), an odoriferous compound evocative of cooked meat, has been reported in red Bordeaux (Bouchilloux et al. 1998b Kotseridis et al. 2000) and de Rioja wines (Aznar et al. 2001). Concentrations of this compound in wine vary from 25 to 140ng/L, with the highest values in Champagnes. As the perception threshold of 2-methyl-3-furanethiol in model dilute alcohol solution is 4 ng/L, this thiol certainly contributes to the toasty aroma in wines. 

Chatonnet, P. (1998). Volatile and odoriferous compounds in barrel-aged wines Impact of cooperage techniques and aging conditions. In A. L. Waterhouse S. E. Ebeler (Eds.), Chemistry of wine flavour, (pp. 180-207). American Chemical Society Washington. 

Volatile and Odoriferous Compounds in Barrel-Aged Wines Impact of Cooperage Techniques and Aging... 

Deodorizing was developed to remove the relativity volatile odoriferous compounds from the host triglyceride. From the early efforts to boil the volatiles at atmospheric conditions and high temperatures, the modern practice of applying heat under low absolute pressure for a particular period of time has developed. As there is a substantial difference between the vapor pressure of the oil and the volatile materials affecting the flavor, color, and stability, deodorizing can consist of any method to evaporate these substances without damaging the oil. 

Another main objective of the deodorization process, besides FFA stripping, is the removal of the odoriferous compounds. Different opinions exist about the time-dependent character of this process. 

Choline, supplied as dietary PC or as free choline, is required in the diet by rats. Although it has not been established that choline is required by humans, it is probably an essential nutrient and may, in the future, be classified as an essential amine or vitamin, Its possible requirement is a concern to clinicians feeding patients by total parenteral nutrition (TpN), In this type of feeding, which may be used for a year or longer, the patient is sustained intravenously with an artificial, chemically defined diet. The choline in foods occurs mainly as PC rather than as free choline. PC is a more desirable dietary component because, when free choline is consumed in large amounts, it is degraded by the gut bacteria to produce trimethylamine, an odoriferous compound (Magil et ai, 1981). 

Bergstrom, G. (1974). Natural odoriferous compounds. X. Macrocyclic lactones in the Dufour gland secretion of the solitary bees Colletes cunicularius and Halictus calceatus (Hymenoptera, Apidae). Chem. Scr. 5, 39-46. 

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],... 

Ethyl lactate is a special case. Its formation is linked to malolactic fermentation and the involvement of an esterase of bacterial origin cannot be excluded. Concentrations of ethyl lactate increase throughout aging via chemical reactions. In Champagne that has completed malolactic fermentation, the ethyl lactate concentration has been observed to increase to a maximum of 2 g/1 after two years and then decrease during further aging on the lees. According to Arctander (1969), ethyl lactate has an odor reminiscent of butter, or even sour milk. Other authors think that the odor of ethyl lactate has been confused with that of other odoriferous compounds. 

When the concentration in must is lower than 50 mg/1, it may be advisable to add 10 g/hl of diammonium phosphate or, preferably, diammonium sulfate [(NH4)2HP04 or (NH4)2S04] to ensure that alcohohc fermentation gets off to a rapid start. The systematic addition of this ammonia salt, without analyzing the must to determine whether it is really necessary, is not recommended. This may, in fact, lead to wines with low concentrations of odoriferous compounds, especially higher alcohols, esters and particularly ethyl acetates of fatty acids. 

Recognition threshold. This is the threshold for the perception and identification of a specific odoriferous compound. 

The many odoriferous compounds released into barrel-aged wine by the oak also have an impact on aroma. 

The term varietal aroma should not, however, be taken to imply that each grape variety has specific volatile compounds. In fact, the same odoriferous compounds and their precursors are found in the musts and wines of several grape varieties in the same family, as well as other fruits or plants. The individual aromatic personality of wines made from each grape variety is due to the infinitely varied combinations and concentrations of the various compounds. 

The odoriferous compounds in Vitis vinifera grapes which have been studied in the greatest detail belong to the terpene family. These compounds are responsible for the characteristic aroma in Muscat grapes and wines, although they are also present (at low concentrations) in simple-flavored varieties. Both free forms and odorless, mainly glycosylated, precursors have been identified in wine and grapes. 

In view of their high perception thresholds (1-5 mg/1), linalol and nerol oxides have very little olfactory impact on wines. Rose oxide is a more odoriferous compound. According to Guth (1997), it is partly responsible for the floral aroma of Gewiirztraminer wines. 

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