Volatile carbonyl

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. 

Virgin olive oil/ Wax and stigmastadienes Virgin olive oil/ Volatile carbonyls... 

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). 

Ranunculus ternatus Thunb. Mao Zhua Chao (leaf) Tannins, phenolic acids, volatile phenols, nonvolatile terpenic compounds, volatile carbonyl and S-containing compounds.60-223 Treat abscesses. 

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. 

The mass spectra of a variety of volatile carbonyl hydrides have been measured.113 Ionization without loss of H is often possible. 

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. 

The number of volatile carbonyls produced by the reaction of glucose and glutamic at pH 5.0,6.5 and 8.0 at 100°C was almost equal. When these systems were heated at 180°C, the number of volatiles was greater and increased more drastically as pH increased to alkalinity (36). The amount of aldehydes produced from mixtures of 0.01M amino acid and 0.1M glucose in water was far below those produced in 0.01M phosphate buffer at pH6.5, which in turn was far below the amount obtained at pH 7.5. The addition of phosphate buffer increased the amount of aldehydes produced signigicantly. The amount of aldehyde produced is also influenced by the chain length of the acid. In general,... 

Space will not be devoted here to emphasis of the vast technological importance of iron and the steels nor to the discussion of ferrous metallurgy. However, typical processes for obtaining cobalt and nickel from natural sources are outlined in Table 24-1. The process for cobalt is somewhat oversimplified, for cobalt ores often contain, in addition to iron and arsenic, nickel, silver, or copper, which must also be removed. Note that nickel is conveniently purified by conversion to its volatile carbonyl, Ni(CO)4, unstable at high temperatures Mond process). 

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-... 

More attention has been given to interaction of proteins with volatile flavors, especially with volatile carbonyls. Nawar (4) found that addition of gelatin to solutions of a homologous series of 2-alkanones caused decreases in their volatilities. Hawrysh and Stine (5) reported on the retention of 2-alkanones in a model system that simulated blue-vein cheese. A similar but more systematic experiment was carried out by Franzen and Kinsella (6). 

Proteins can bind flavor constituents, especially volatile carbonyls. When bound to protein, some volatile aldehydes behave as if they were non-volatile compounds and are retained over a long period of time during storage. Such interaction may cause chemical as well as organoleptical deterioration of food proteins. 

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... 

Under strongly redncing conditions, several transition metals may also be mobilized - from decomposing biomass or beginning with certain enzymes snch as hydrogenases as precnrsors - as homoleptic, volatile carbonyl complexes (Mo, Ni, W, not Fe) this reaction (Feldmann 1999) thus extends beyond the small range of transition metals which directly form carbonyl complexes npon contact of the bnlk or dispersed (dust, amalgam) metal with CO (Elschenbroich and Salzer 1988). 

Gas Chromatography Volatile carbonyls and hydrocarbons Direct headspace Rapid analysis All samples... 

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... 

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