Search results for "Vacuum distillation"
showing 6 items of 6 documents
Neutral volatile compounds in the raw milks from different species
1993
SummaryA comparative study was carried out on the flavour constituents of bovine, ovine, caprine and water buffalo fresh raw milks. The volatiles were isolated from milks by means of vacuum distillation and liquid–liquid extraction. Eighty neutral volatile compounds were identified using high resolution gas chromatography (HRGC) and HRGC-mass spectrometry. About 30 of these components have not been detected previously in milk. The volatiles in milk were similar for the four species, although several quantitative differences might explain the different odours. The volatiles consisted mainly of ethyl esters, especially those derived from butyric and hexanoic acids. Dimethylsulphone alone comp…
Comparison of the relative quantities of aroma compounds found in fresh apricot (Prunus armeniaca) from six different varieties
1988
The volatile components of fresh apricot (Prunus armeniaca) were isolated by vacuum distillation and fractionated on a silica gel column. Analysis by gaschromatography coupled with mass spectrometry led to the identification of 82 compounds, 60 of which were found for the first time in this fruit. Six varieties, cultivated in the south of France were compared for their firmness, acidity, sweetness and for their content of 56 volatile components. Precoce de Tyrinthe was the least aromatic variety, but produced fruits very early in the season. Palsteyn gave acidic but rather aromatic fruits. Moniqui possessed large but perishable fruits with flowery aroma due to the presence of terpenic keton…
Polycrystalline TiO2 impregnated with cardanol-based porphyrins for the photocatalytic degradation of 4-nitrophenol
2004
Hydrogenated cardanol (3-n-pentadecylphenol), a renewable organic resource obtained by vacuum distillation of roasted “cashew nut shell liquid” (CNSL), a by-product of the cashew industry, has been used to synthesize novel lipophilic porphyrins. Polycrystalline TiO2 impregnated with these novel “cardanol-based” porphyrins as sensitizers has been investigated in the photodegradation of 4-nitrophenol (4-NP) in aqueous suspension. The results indicated that the presence of the sensitizer enhances the photoactivity of polycrystalline bare TiO2 in the process. The activating effect was higher in the case of the Cu-complex.
Mild Hydrocracking of Vacuum Gasoil over NiMo-Beta Zeolite Catalysts: The Role of the Location of the NiMo Phases and the Crystallite Size of the Zeo…
1998
Abstract Mild hydrocracking composite catalysts based on NiMo/γ-Al2O3-Beta zeolite have been prepared and the influence of the location of the NiMo phases has been studied. A good hydrocracking activity and the highest HDS conversion was found during the hydrocracking of a vacuum gasoil with the composite catalyst where the NiMo is located on the alumina component and then mixed with the zeolite in a proportion of 1 : 1 by weight. The crystal size of the beta zeolite had a significative influence on the catalytic behaviour, being better the smaller the crystallite size is. The small crystallite beta-based catalyst displayed a higher hydrocracking activity than conventional USY and silica-al…
Quantification of some volatile aromatic compounds of apricot by adding standards
1988
The quantification of twelve volatile aromatic compounds of apricot was realized by adding known amounts of pure compounds directly in the slurry before analysis by vacuum distillation and gas chromatography. This method was compared with the classical technique using an internal standard and was applied to two different apricot cultivars. Large differences were observed between the amounts of volatiles calculated by the two methods. They are due to the differences between the extraction coefficients of the quantified compounds and to the retentions of volatiles on nonvolatile compounds, which may vary according to the polarity.
Volatile components of dry-cured ham
1991
The volatile components of dry-cured ham were isolated by vacuum distillation and analyzed by gas chromatography-mass spectrometry. The structures of 76 molecules were identified by mass spectrometry, cochromatography, or measured Kovats indices. The compounds identified may come from the catabolism of the main constituent parts of the meat (glucids, lipids and protids) during the curing of the hams, from the pig feed, or from technological processes. The volatile compounds extracted from 50 g of ham according to the technique described correspond to a chromatographical surface equivalent to 0.12 mg of the dodecane internal standard, or approximately 2.4 ppm of the weight of the sample. Fla…