Search results for "AROMA"
showing 10 items of 1006 documents
Interaspecific chemical variability and highlighting of chemotypes of leaf essential oils from Ravensara aromatica Sonnerat, a tree endemic to Madaga…
2006
Ravensara aromatica Sonnerat is a tree endemic to Madagascar. The essential oil extracted from the leaves is used in aromatherapy. Previous chemical studies have generated some confusion with regard to the chemical composition of this essential oil. In order to eliminate this uncertainty, we undertook a systematic evaluation of the chemical composition of essential oils from leaves of this species. The study focused on 28 individual samples formally identified as R. aromatica. The essential oils were obtained by hydrodistillation and analysed by GC and GC–MS. It was possible to distinguish four groups of trees through principal components analysis and agglomerative hierarchical clustering a…
Fluorinated Heterocyclic Compounds. An Effective Strategy for the Synthesis of Fluorinated Z-Oximes of 3-Perfluoroalkyl-6-phenyl-2H-1,2,4-triazin- 5-…
2005
The reaction of 3-benzoyl-5-perfluoroalkyl-1,2,4-oxadiazoles with hydrazine has been investigated, evidencing the possibility of competitive reaction paths. Nucleophilic addition of the hydrazine to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring opening and ring closure with enlargement, leads with high yield and in very mild experimental conditions to the formation of Z-oximes of 3-perfluoroalkyl-6-phenyl-2H-1,2,4-triazin-5-ones (11a-c) as major products of the reaction. In turn, the hydrazine can attack the electrophilic carbonyl carbon giving 4-perfluoroacylamino-5-phenyl-2H-1,2,3-triazoles (13a-c) through the well-known Boulton-Katritzky rearrangement of the inter…
On the Nucleophilic Reactivity of 4,6-Dichloro-5-nitrobenzofuroxan with Some Aliphatic and Aromatic Amines: Selective nucleophilic substitution
2020
The reaction rates for the nucleophilic aromatic substitution of 4,6-dichloro-5-nitrobenzofuroxan 1 with eight aliphatic amines (characterized by very different basicities/ nucleophilicities) and three anilines have been measured in both methanol and toluene. The obtained rates have been related to the basicity (pKaH in water and Kb in benzene) or nucleophilicity (N Mayr constants) of the tested amines. The whole of the obtained kinetic data has furnished useful information on the high nucleophilic reactivity of benzofuroxan derivatives, which has been related essentially to two factors: the high electron-drawing ability/power of the condensed furoxan ring and the low aromatic character of …
Study of the retention and release of n-hexanal incorporated into soy protein isolate–lipid composite films
2010
[EN] This work deals with the study of the kinetic of aroma release, which had been previously incorporated into soy protein isolate (SPI)-lipid composite films. The aim was to determine the influence of type and amount of lipidic material on aroma (n-hexanal) release and retention, as well as the apparent diffusion coefficients. To carry out this study it have been employed SPI-based films containing two SPI:LIPID ratios (1:0.25 and 1:0.5), and two types of lipids, oleic acid (OA) and beeswax (BW), in OA:BW ratios 100:0, 70:30, 50:50, 30:70 and 0:100. The measurements were performed by a gas chromatography technique. The films that showed more retention were SPI:LIPID 1:0.5 100% BW and con…
Microbiological and technological parameters impacting the chemical composition and sensory quality of kombucha
2020
International audience; Kombucha is a beverage made from sugared tea transformed by yeasts and acetic acid bacteria. Being originally homemade, it has become an industrially produced soft drink whose quality standards are poorly defined and whose production process is still not fully controlled. Based on current knowledge in beverages, links between kombucha's chemical composition and sensorial compounds are drawn. Macromolecules create turbidity, whereas uncharacterized tea pigments derivatives participate in the color. Residual sugars bring sweetness and organic acids produced by acetic acid bacteria form its characteristic sour taste. Acetic acid is also part of its aroma profile, althou…
Preliminary characterization of wild lactic acid bacteria and their abilities to produce flavour compounds in ripened model cheese system.
2007
Aims: The aim of this work was to preliminary characterize wild lactic acid bacteria (LAB), previously isolated during artisanal Pecorino Siciliano (PS) cheese-making for technological and flavour formation abilities in a model cheese system. Methods and Results: Twelve LAB were studied for the ability to grow at 10 and 45°C, to coagulate and acidify both reconstituted skim milk and ewe's milk. Moreover, the capacity of the strains to generate aroma compounds was evaluated in a model cheese system at 30- and 60-day ripening. Flavour compounds were screened by sensory analysis and throughout gas chromatography (GC)–mass spectrometry (MS). Most of the strains were able to grow both at 10 an…
Catalytic activity of rare-earth-supported catalysts in Friedel–Crafts acylations
1999
Abstract Friedel–Crafts acylations are catalysed by rare-earth-supported catalysts. The preparation, characterization and performance of these solid catalysts in a test acylation reaction and in a variety of syntheses of aromatic ketones are reported. In contrast to the reactions using AlCl3, the experimental conditions are non-polluting and the final work-up does not require any aqueous treatment.
Chemical Composition of Two Different Lavender Essential Oils and Their Effect on Facial Skin Microbiota
2019
Lavender oil is one of the most valuable aromatherapy oils, its anti-bacterial and anti-fungal activities can be explained by main components such as linalool, linalyl acetate, lavandulol, geraniol, or eucalyptol. The aim of the study was to assess the anti-microbial effects of two different lavender oils on a mixed microbiota from facial skin. The commercial lavender oil and essential lavender oil from the Crimean Peninsula, whose chemical composition and activity are yet to be published, were used. Both oils were analysed by gas chromatography coupled to mass spectrometry. The composition and properties of studied oils were significantly different. The commercial ETJA lavender oil contain…
Biotechnological Approaches to Increase Essential Oil Yield and Quality in Aromatic Plants: The Lavandula latifolia (Spike Lavender) Example. Past an…
2019
Increasing knowledge about isoprenoid biosynthesis pathways has provided new tools for aromatic plant breeding using biotechnological approaches. Notably, there are possibilities to modify essential oil profiles and enhance production of valuable monoterpenes. This attains a particular significance in Lavandula latifolia Medik. (spike lavender), one of the most important essential oil crops in Spain. This chapter summarizes work done to improve essential oil yield and quality by engineering: (1) the enzymes controlling regulatory steps of methyl-D-erythritol 4-phosphate (MEP) and mevalonic acid (MVA) pathways to increase C5 units employed for monoterpene biosynthesis and (2) the monoterpene…
Visible-light photoredox catalyzed synthesis of pyrroloisoquinolines via organocatalytic oxidation/[3 + 2] cycloaddition/oxidative aromatization reac…
2014
Beilstein journal of organic chemistry 10, 1233-1238 (2014). doi:10.3762/bjoc.10.122