Volatile phenols origin

Volatile phenols originate from hydroxycinnamic acids (ferulic, p-coumaric, or caffeic acid) by the action of hydroxycinnamate decarboxylase enzyme, which turn the hydroxycinnamics acid into vinylphe-nols (Albagnac, 1975 Grando et al., 1993). Then, these compounds are reduced to ethyl derivatives by vinylphenol reductase enzymes characteristic of species, such as Dekkera bruxellensis, Dekkera anomala, Pichia guillermondii, Candida versatilis, Candida halophila, and Candida mannitofaciens (Edlin et al., 1995 1998 Dias et al., 2003 Chatonnet et al., 1992 1995 1997 Dias et al., 2003), apart from very small quantities produced by some yeasts and lactic acid bacteria under peculiar growth conditions (Chatonnet et al., 1995 Barata et al., 2006 ... 

Dubois, P. (1983) Volatile Phenols in Wines, in Flavour of distilled beverages, origin and development, J.R. Piggot (Ed.) Chichester Ellis Horwood. 

Dubois P. (1983) Volatile phenols in wines. Flavour of Distilled Beverages. Origin and Development. Piggott J.R. Ed., Ellis Horwood, Chichester, p. 110. 

Oak from different origins is odoriferous to varying degrees. Its characteristic odors are mainly revealed during seasoning and barrel manufacture. Heating (Section 13.8.3) forms furanic derivatives, volatile phenols and phenylketones, as well as increasing concentrations of phenol aldehydes and lactones. 

Until recently, most of the chemical research on the contents of these structures was directed at the identification of the constituents of castoreum. In the late 1940s Lederer [72, 73] identified 36 compounds and some other incompletely characterized constituents in castoreum of uncertain origin. Other constituents were subsequently identified in the material [74-77]. In a reinvestigation aimed specifically at the phenol content of the material, Tang et al [69] identified 10 previously unreported phenols in the castoreum from the North American beaver, Castor canadensis. Of the 15 phenols reported elsewhere, only five were confirmed in this analysis, in addition to 10 phenolic compounds that were not reported elsewhere. It was concluded that the 10 previously identified phenols that were not found in the study by Tang et al. were either absent or were not volatile enough to be detected by the methods employed. This was most probably because a relatively low maximum column temperature of only 210 °C was employed in the GC-MS analyses. The compounds identified by Lederer,... 

In meats, of course, there are components which arise from the protein which cannot be present in the products from pure fat. Table III shows some of the sulfur compounds and aromatic compounds which are also found in irradiated meats. Many of these can be postulated as arising from direct bond cleavage of amino acid moieties. Benzene and toluene may come from phenylalanine and phenol and p-cresol from tyrosine. Recent studies have been directed to considering the origin of some of the compounds from proteinaceous substances. Some of the sulfides, disulfides, and mercaptans can derive directly from cysteine or methionine, but those containing more than two carbon atoms in a chain require more than a superficial explanation. In order to evaluate the contribution of the volatiles from the protein as well as the lipid constituents of meat, volatile components produced in various protein substances have also been analyzed. 

The objectives of the extender-filler in glue mixes are to improve the adhesive performance, to help control the mix viscosity and to conserve the phenolic and urea adhesives. These fillers and extenders serve specific needs in these glue mixes. They extend the resin solution from its original non-volatile state to lower levels, such as 26 percent resin solids in the mix. They also function as a means of maintaining the very low resin molecular weight and size molecules on the surface when they are applied to the veneer to prevent over-penetration prior to hot press pressure and temperature which gels the resin to a permanently set condition. 

---