Volatile carbonyl compounds

In these cases, one is limited to the growth of single crystals of the transition metals since it is those metals which form volatile carbonyl compounds. The alkali metals, alkaline earth metals and certain of those elements which are allotropic in nature are not at aH suited for this type of crystal growth. 

Ciccioli, P., E. Brancaleoni, M. Frattoni, A. Cecinato, and A. Bra-chetti, Ubiquitous Occurrence of Semi-Volatile Carbonyl Compounds in Tropospheric Samples and Their Possible Sources, Atmos. Environ., 27A, 1891-1901 (1993a). 

Bassette, R. and Keeney, M. 1960. Identification of some volatile carbonyl compounds from nonfat dry milk. J. Dairy Sci. 43, 1744-1750. 

Day, E. A., Forss, D. A. and Patton, S. 1957. Flavor and odor defects of gamma-irradiated skim milk. I. Preliminary observations and the role of volatile carbonyl compounds. J. Dairy Sci. 40, 922-931. 

Describes a simple and sensitive spectrophotometric method to estimate the content of total carbonyl compounds in rancid fats and foods by trapping them with 2,4-DNPH the technique determines total carbonyls, including those that are nonvolatile, decreasing the ability of the assay to correlate well with sensory data. Although gas chromatographic techniques are better suited for determining volatile carbonyl compounds from lipid oxidation, this is still the classical colorimetric assay. 

Forss et al. (1960a,c) compared the qualitative and quantitative distribution of carbonyl compounds in dairy products with fishy, tallowy or painty off-flavor. Total content of volatile carbonyl compounds was approximately 10 times greater in the tallowy and 100 times greater in the painty butterfat than in fishy butterfat. Tallowy butterfat contained greater amounts of -heptanal, -octanal, -nonanal, 2-heptanone 2-heptenal and 2-nonenal, while painty butterfat contained greater amounts of K-pentanal and C5 to C10 alk-2-enals. 

Parks, O.W., Patton, S. 1961. Volatile carbonyl compounds in stored dry whole milk. J. Dairy Sci. 44, 1-9. 

The Mond Process 3 is based upon the fact that nickel readily combines with carbon monoxide at 50-80° C. to form a volatile carbonyl compound of composition Ni(CO)4, which decomposes at higher tem-... 

In our opinion, the predominant contribution to flavor seems to come from sulfurous and carbonyl-containing volatiles. While many of the sulfur-containing volatiles are known to have meaty aromas, volatile carbonyl compounds generally are formed by lipid autoxidation/degradation and do not possess meaty flavor notes. However, it has been indicated that the carbonyl compounds are responsible for the "chickeny" aroma of cooked chicken (17). Thus, lipid autoxldatlon appears to yield the character impact compounds for chicken (18). 

It may then be reasonable to postulate that meat on cooking acquires a characterisltlc species flavor which Is caused by the volatile carbonyl compounds formed by oxidation of its lipid components. Due to the strong antioxidant activity of nitrite, however, such oxidation products are either absent or are present... 

The volatile carbonyl compounds formed during oxidation of fats and oils are major contributors to off-flavor development. Therefore, there have been significant efforts at identifying and quantifying these compounds. It is difficult to analyze these compounds in fats and oils for several reasons. First, it is difficult to remove... 

Decomposition and condensation of hydroperoxides also produces a multitude of nonvolatile monomeric products, including di- and tri-oxygenated esters, and dimeric and polymeric materials, especially at elevated temperature. Many of these dimers and polymers are known to be rich sources of volatile carbonyl compounds and to decrease the flavor and oxidative stability of soybean oil (316). These high-molecular-weight materials also can produce a series of physical and chemical changes to the oil and food products, including increased viscosity, polarity, free acid content, development of dark color, and an increased tendency of the oil to foam (233). 

Pippen, E.L., Nonaka, M. (1960) Volatile carbonyl compounds of cooked chicken. II. Compounds volatized with steam during cooking. Food Res. 25, 764-769... 

Freshly stir-fried Chinese food has a much better flavor quality than after it is aged. The main change in volatile constituents of stir-fried bell peppers during aging is the production of volatile carbonyl compounds from autoxidative breakdown of unsaturated fatty acids (Wu et al., 1986). 

Lin Y, Duecker SR, Jones AD, et al. 1995. Protocol for collection and HPLC analysis of volatile carbonyl compounds in breath. Clin Chem 41 1028-1032. 

Bevllacqua (7, 8, 9, 10)studied the change in molecular weight and the volatile products In the thermal oxidation of synthetic and natural polylsoprene. At 90°C It appeared that every mole of chain scission was accompanied by one mole of a volatile carbonyl compound. Bevllacqua suspected this compound was levullnaldehyde, and this has been substantiated by Percy (11) and Houseman (12) In the oxidation of purified sol rubber at 75 C. Levullnaldehyde could result from the chain scission of a cyclic peroxide structure similar to the Bolland structure ... 

Purification via the volatile carbonyl compounds is similar to the van Arkel process, though used widely only for nickel ... 

A method for concentration of volatile carbonyl compounds, based on intermediate formation of their semicarbazides with subsequent liberation of the starting compounds by heating with phosphoric acid was described by Hunter and Walden [71]. Analogous methods can be developed for other classes of compounds. 

Of the approximately 4800 substances in tobacco smoke (1373), 44 are beheved...to be relevant to tobacco-related diseases (23A06). These include... some volatile carbonyl compounds, tobacco-specific A-nitrosamines, aromatic amines, phenols, volatile alkenes, benzo[a]pyrene and metals. These substances are sometimes called colloquially Hoffmann analytes since similar lists of toxicological substances have been proposed by Dietrich Hoffmann et al. of the American Health Foundation in New York since the mid 1980s. The latest compilation by Hoffmann et al. lists 82 substances (1741,1743, 1744). 

Brunnemann, K.D., R. Onrust, and D. Hoffmann Determination of volatile carbonyl compounds in tobacco headspace and tobacco smoke 40th Tobacco Chemists Research Conference, Program Booklet and Abstracts, Vol. 40, Paper No. 47, 1986, p. 25. 

Miyake, T. and T. Shibamoto Quantitative analysis by gas chromatography of volatile carbonyl compounds in cigarette smoke J. Chromatog. 693 (1995) 376-381 Miyano, M., H. Matsushita, and N. Yasumatsu A -lsopropylnomicotine in burley tobacco Agr. Biol. Chem. 43 (1979) 2205-2206. 

Slemr J. (1991) Determination of volatile carbonyl compounds in clean air. Fresenius J. Anal. Chem., 340, 672-677. 

Some Volatile Carbonyl Compounds from Autoxidized Unsaturated Fatty Acids... 

Schiberle, P. and Grosch, W. Model experiments about the formation of volatile carbonyl compounds. /. Am. Oil Chem. Soc. 58, 602-607 (1981). 

Odor threshold values of volatile carbonyl compounds produced by lipid... 

These secondary products of oxidation can also be determined by gas chromatography or HPLC, either directly or after preparing suitable derivatives. The HPLC method is less sensitive than the direct gas chromatography methods. HPLC can be carried out under mild conditions and is subject to less artifacts than gas chromatographic methods, which require higher temperatures. However, HPLC requires the use of organic solvents, which cause losses of volatile carbonyl compounds. HPLC is also unsuitable for the determination of volatile hydrocarbons formed by decomposition of hydroperoxides. 

The volatile carbonyl compounds developed from milk fat oxidation are detectable at extremely low levels (parts per bilhon). Flavor compounds are less volatile and mainly retained by the fat component. These compounds are thus much more easily perceived in milk, where they have much lower threshold values (0.004-0.1) than in oil systems (0.1-2.5). Because flavor compounds are very easily perceived in milk products, they can be detected at extremely low levels of oxidation. Fluid milk becomes rancid at peroxide values less than one. 

Grosch, W. Linoleic and Unolenic acid as substrate for enzymatic formation of volatile carbonyl compounds in pea. Z Lebensm. Unters.-Forsch. 137, 216- (1968)... 

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