Search results for "Lep"
showing 10 items of 3622 documents
Solid Phase Microextraction (SPME) of Orange Juice Flavor: Odor Representativeness by Direct Gas Chromatography Olfactometry (D-GC-O)
2003
The sensorial quality of solid phase microextraction (SPME) flavor extracts from orange juice was measured by direct gas chromatogrphy-olfactometry (D-GC-O), a novel instrumental tool for evaluating odors from headspace extracts. In general, odor impressions emerging from SPME extracts poorly resembled that of the original orange juice. In an attempt to improve the sensorial quality of extracts, sample equilibration and exposure times were varied on Carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) SPME fibers. Best sensorial results were obtained with the DVB/CAR/PDMS fiber exposed for the shortest time; a trained panel of eight assess…
Chemical composition and phytotoxic effects of essential oils of Salvia hierosolymitana Boiss. and Salvia multicaulis Vahl. var. simplicifolia Boiss.…
2009
The chemical composition of the essential oils of S. hierosolymitana Boiss. and S. multicaulis Vahl. var. simplicifolia Boiss. collected in Lebanon was studied by means of GC and GC-MS analysis. In all 115 compounds were identified: 82 for S hierosolymitana and 72 for S. multicaulis var. simplicifolia. The presence of carbonylic compounds (17%) characterizes the oil from S. hierosolymitana, while S. multicaulis var. simplicifolia oil is rich of monoterpenes (34.5%) and sesquiterpenes (46.9%). The effects of the essential oils on germination and initial radical elongation of Raphanus sativus L. (radish) and Lepidium sativum L. (garden cress) were studied, indicating in a different activity a…
Influence of packaging on the aroma stability of strawberry syrup during shelf life
2001
Different types of packaging (glass bottle, PVC, and PET) were compared for the preservation of aroma quality of a strawberry syrup during shelf life. Esters, alcohols, and aldehydes were analyzed by solid-phase micro-extraction (SPME) and solvent extraction. During storage, hydrolysis of esters in acids and alcohols led to a modification of the aroma profile which can be explained by the replacement of “fruity” and “fresh” notes by “dairy note” in the syrup. Aroma compounds that are responsible for fruity notes, such as methyl cinnamate, methyl anthranilate, and methyl dihydrojasmonate, were strongly reduced after 90 days. This could be explained by a selective interaction of these compoun…
Bio-phenols determination in olive oils: Recent mass spectrometry approaches
2021
Extra virgin olive oil (EVOO) is largely used in Mediterranean diet, and it is also worldwide apprised not only for its organoleptic properties but also for its healthy effects mainly attributed to the presence of several naturally occurring phenolic and polyphenolic compounds (bio-phenols). These compounds are characterized by the presence of multiple phenolic groups in more or less complex structures. Their content is fundamental in defining the healthy qualities of EVOO and consequently the analytical methods for their characterization and quantification are of current interest. Traditionally their determination has been conducted using a colorimetric assay based on the reaction of Folin…
Identification of compounds responsible for the odorant properties of aromatic caramel
2012
Aromatic caramel results from the heat treatment of sugars under specific temperature conditions. Because of its richness in aroma compounds and its pleasant organoleptic properties, caramel is widely used in the food industry. However, the composition of the volatile odorant fraction has not been completely elucidated. The aim of this work was thus to identify the volatile odorant compounds responsible for caramel sensory properties using a multivariate statistical technique. Four aromatic caramels differing in terms of their carbohydrate composition and cooking process were chosen. Odorant compounds were screened by gas chromatography–olfactometry (GC-O) and identified by GC–mass spectrom…
Use of the Apparent Content Curves for the spectrophotometric identification of substances: identification of amphetamines
1994
The possibility of identification of substances which have similar spectral behaviour by means of Apparent Content Curves has been studied. This study is carried out with absorption, excitation and emission spectra of several amphetamines of widespread pharmaceutical use. Results obtained show that amphetamine, phenylpropanolamine, pseudoephedrine, phenylephrine, epinephrine, dopamine and methoxyamphetamine can be identified with a probability of >95%.
Chronic exposure to a GSM-like signal (mobile phone) does not stimulate the development of DMBA-induced mammary tumors in rats: results of three cons…
2002
Certain epidemiological and experimental studies raised concerns about the safety of radiofrequency (RF) electromagnetic fields because of a possible increased risk of leukemia and lymphoma. In this study, an RF field used in mobile telecommunication was tested using 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors in female Sprague-Dawley rats as a model for human breast cancer. Three experiments were carried out under strictly standardized conditions and were started on the same day of three consecutive years. The field consisted of a GSM-like signal (900 MHz pulsed at 217 Hz, pulse width 577 micros) of relatively low power flux density (100 microW/cm(2) +/- 3 dB) and was appl…
The metabolic profile of lemon juice by proton HR-MAS NMR: the case of the PGI Interdonato Lemon of Messina
2015
We have studied by means of High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) the metabolic profile of the famous Sicilian lemon known as 'Interdonato Lemon of Messina PGI'. The PGI Interdonato Lemon of Messina possesses high organoleptic and healthy properties and is recognised as one of the most nutrient fruits. In particular, some of its constituents are actively studied for their chemo-preventive and therapeutic properties. In this paper, we have determined by means of HR-MAS NMR spectroscopy the molar concentration of the main metabolites constituent the juice of PGI Interdonato Lemon of Messina in comparison with that of the not-PGI Interdonato Lemon of Turk…
Interdonato lemon from Nizza di Sicilia (Italy): chemical composition of hexane extract of lemon peel and histochemical investigation
2015
Considering that the determination of authenticity and of the geographical origin of food is a very challenging issue, in this study we studied by means of histological and histochemical analyses the famous Sicilian lemon known as ‘Interdonato Lemon of Messina PGI’. Since the protected geographical indication Interdonato lemon of Messina possesses high organoleptic properties, the composition of the hexane extract of lemon peel was determined by HRGC and HRGC–MS analyses and compared with that of lemon of different cultivars. The results obtained are informative of the oil’s quality and explain the variation of the lemon essential oil composition. Given the fundamental economic implications…
Energy regulatory signals and food reward.
2009
The hormones insulin, leptin, and ghrelin have been demonstrated to act in the central nervous system (CNS) as regulators of energy homeostasis, acting at medial hypothalamic sites. Here, we summarize research demonstrating that, in addition to direct homeostatic actions at the hypothalamus, CNS circuitry that subserves reward and is also a direct and indirect target for the action of these endocrine regulators of energy homeostasis. Specifically, insulin and leptin can decrease food reward behaviors and modulate the function of neurotransmitter systems and neural circuitry that mediate food reward, the midbrain dopamine (DA) and opioidergic pathways. Ghrelin can increase food reward behavi…