1,721,149 research outputs found
Isolation and characterization of antimicrobial food components
No full textNowadays there is an evident growing interest in natural antimicrobial compounds isolated from food matrices. According to the type of matrix, different isolation and purification steps are needed and as these active compounds belong to different chemical classes, also different chromatographic and electrophoretic methods coupled with various detectors (the most used diode array detector and mass spectrometer) have to be performed. This review covers recent steps made in the fundamental understanding of sample preparation methods as well as of analytical tools useful for the complete characterization of bioactive food compounds. The most commonly used methods for extraction of natural antimicrobial compounds are the conventional liquid-liquid or solid-liquid extraction and the modern techniques such as pressurized liquid extraction, microwave-assisted extraction, ultrasound-assisted extraction, solid-phase micro-extraction, supercritical fluid extraction, and matrix solid phase dispersion. The complete characterization of the compounds is achieved using both monodimensional chromatographic processes (LC, nano-LC, GC, and CE coupled with different type of detectors) and, recently, using comprehensive two-dimensional systems (LC×LC and GC×GC)
Advances in the analysis of veterinary drug residues in food matrices by capillary electrophoresis techniques
Full text linkIn the last years, the European Commission has adopted restrictive directives on food quality and safety in order to protect animal and human health. Veterinary drugs represent an important risk and the need to have sensitive and fast analytical techniques to detect and quantify them has become mandatory. Over the years, the availability of different modes, interfaces, and formats has improved the versatility, sensitivity, and speed of capillary electrophoresis (CE) techniques. Thus, CE represents a powerful tool for the analysis of a large variety of food matrices and food-related molecules with important applications in food quality and safety. This review focuses the attention of CE applications over the last decade on the detection of different classes of drugs (used as additives in animal food or present as contaminants in food products) with a potential risk for animal and human health. In addition, considering that the different sample preparation procedures have strongly contributed to CE sensitivity and versatility, the most advanced sample pre-concentration techniques are discussed here
Natural organic substances with antioxidant activity in dietary vegetables.
No full textDuring the past two decades, epidemiological studies have pointed out clear relations between diet, chronic diseases (cardiovascular, neoplastic, inflammatory, and neurodegenerative pathologies and aging) and the protective effects following the consumption of vegetables and fruits. For a long time antioxidant vitamins and beta-carotene were considered responsible for the protective effects. In recent years it became apparent that other dietary vegetable components, in particular phenols, which are ubiquitous in plants, can strongly contribute to the positive effects of vegetable foods.
Reactive oxygen sunstances (ROS) and reactive nitrogen substances (RNS), in particular free radicals, initiate and accelerate lipid peroxidation, which in foods damage the flavour of fat and oil products and in living organisms they attack and damage the most important biological molecules, such as DNA, lipids, proteins, carbohydrates, and alter their chemical structure and biological functions.
The importance of the availability of natural antioxidants that can contrast the action of free radicals both in chemical and in biological systems, promoted the investigation of plant materials. Plant materials are known to contain many different antioxidant components that can act as free radical scavengers and singlet oxygen quenchers. Among these ones plant foods are particularly interesting because it is demonstrated that consumption of fruits and vegetables protects living organisms from oxidative damage.
The aim of this study is to investigate the specific antiradical activities both peroxyl- and hydroxyl-radicals of some vegetables commonly used in the Mediterranean diet, and the influence of technological treatment on such activities
Screening for valuable secondary metabolites in Berberis species native from Colombia
No full textThe genus Berberis L., of the family Bereberidaceae, comprises approximately 450-500 species of deciduous evergreen shrubs, found in temperate and sub-tropical regions of Asia, Europe and America. The distribution in the Neotropic is restricted to mountain regions, generally above 2000 m. Forty-two species are endemic to Colombia and the alkaloids (berberine) have been found to have antibacterial, antifungal, anti-inflammatory and antioxidant activity.
In this study we evaluated the composition of different fractions of extracts of the whole plant from some species of Berberis L. native to Colombia by GC-MS and HPLC/DAD-ESI-MS
Metodo RP-HPLC per la determinazione della degradazione ossidativa dei lipidi alimentari
No full textI lipidi sia cellulari che alimentari vanno soggetti alla degradazione ossidativa che ne altera le caratteristiche funzionali, biologiche ed organolettiche e porta alla formazione di numerosi composti, alcuni dei quali tossici per il nostro organismo.
Sono stati messi a punto numerosi metodi che attraverso la determinazione delle diverse classi di composti quali i perossidi, derivati carbonilici, dieni coniugati, idrocarburi, composti fluorescenti o polari, permettono di seguire l'andamento di questo processo, ma nessuno è in grado di dare un quadro esauriente dello stato di perossidaizone di un lipide.
E' tuttavia generalmente riconosciuto che la determinazione dei composti polari fornisce la misura più attendibile dell'estensione del processo degradativo. Per questo abbiamo pensato di analizzare l'olio perossidato in seguito a trattamento termico, mediante cromatografia HPLC in fase inversa, utilizzando una miscela eluente polare che permette di studiare questa frazione. Sono stati analizzati campioni di olio di arachidi, soia, girasole, vinaccioli e oliva. Nelle condizioni applicate ogni olio mostra un profilo cromatografico caratteristico, tuttavia dopo trattamento termico, tutti gli olii mostrano un picco con lo stesso tempo di ritenzione rilevabile dopo un periodo di riscaldamento variabile dipendentemente dall'olio analizzato e dalla temperatura applicata. Ulteriori analisi condotte sull'olio di girasole e arachidi, hanno mostrato che l'area di tale picco aumenta all'aumentare della temperatura e del periodo di riscaldamento. Gli incremente dell'area del picco cromatografico in funzione di queste variabili seguono lo stesso andamento del numero di p-anisidina e dell'assorbività dei dieni coniugati determinati sugli stessi campioni di olio. Questo sembra indicare che tale picco sia da porre in relazione con i prodotti secondari della perossidazione piuttosto che con i perossidi che per temperature superiori a 145°C, per uno stesso tempo di riscaldamento, diminuiscono con l'aumentare della temperatura.
L'analisi più approfondita dei componenti responsabili di questo picco permetterà di individuare uno o più composti che potranno essere utilizzati come indici dello stato di perossidazione di un lipidie
Food components with anticaries activity
No full textCaries is the most common oral infectious disease in the world. Its development is influenced also by diet components that interfere with pathogen mutans group Streptococci (MGS) activity. A very active research to identify functional foods and their components that are generally recognised as safe has been ongoing, with the aim of developing alternative approaches, to the use of synthetic chlorhexidine, and at the reduction or prevention of caries. Until now convincing evidence exists only for green tea as a functional food for oral health, partly owing to its high content of catechins, especially epigallocatechin-gallate. A number of other foods showed potential anticaries activity. Some other foods able to act against MGS growth and/or their virulence factors in in vitro tests are: apple, red grape seeds, red wine (proanthocyanidins), nutmeg (macelignan), ajowan caraway (nafthalen-derivative), coffee (trigonelline, nicotinic and chlorogenic acids, melanoidins), barley coffee (melanoidins), chicory and mushroom (quinic acid). In vivo anticaries activity has been shown by cranberry (procyanidins), glycyrrhiza root (glycyrrhizol-A), myrtus ethanolic extract, garlic aqueous extract, cocoa extracts (procyanidins), and propolis (apigenin, tt-farnesol)
A new millifluidic-based gastrointestinal platform to evaluate the effect of simulated dietary methylglyoxal intakes
No full textThe search for new in vitro modular bioreactors to simulate flow-mediated transport and absorption of chemical substances is a very important issue in toxicology and in drug and bioactive delivery research. The possibility of setting up a dynamic microenvironment leads to experimental conditions that may more closely resemble the in vivo model, especially to measure acute or chronic intake of compounds. We propose a novel millifluidic-based gastrointestinal model as an evolution of the common in vitro methods, to evaluate the exposure to exogenous methylglyoxal (MGO), a highly reactive α-oxoaldehyde responsible for the formation of advanced glycation end products involved in a number of chronic diseases. Gastric and intestinal cells were seeded into two different chambers, creating a multi-compartmental system where fluids dynamically interact with human gastric stromal and intestinal cells. MGO was tested at concentrations simulating different MGO food intakes (meal, daily, and hypothetically weekly). Cell viability was measured over time, and simultaneously, extracellular MGO was quantified by a validated RP-HPLC-DAD method to evaluate its absorption/metabolization. This new platform gives the opportunity to connect different compartments, allowing studying kinetic and metabolic profiles of different substances and representing a very promising alternative to animal models, at least in preliminary investigations
Anti- and pro-oxidant water soluble activity of Cichorium genus vegetables and effect of thermal treatment
No full textBoth the pro- and antiradical water soluble activity, toward DPPH¥, ROO¥, OH¥ radicals found in seven
diet vegetables belonging to the Cichorium genus, and the effects of boiling, freezing, and freezedrying
on such activities were investigated. The vegetables were three red cultivars of Cichorium
intybus var. silvestre from three different areas of production, that is, chicory from Chioggia, Treviso,
and Verona, C. intybus var. foliosum (Belgian chicory), C. endivia var. latifolium (escarole), C. endivia
var. crispum (“crispa”), and a hybrid vegetable obtained by the cross between C. intybus var. silvestre
and C. endivia var. latifolium (chicory from Castelfranco). The juices obtained by simple centrifugation
of vegetables operating at 2 or 25 °C and submitted to the thermal technological treatments were
assessed for antiradical activity using the DPPH¥ assay, the linoleic acid-â-carotene system, and
the deoxyribose assay. In all three assays used, each vegetable juice was shown to possess antiradical
activity; there was a significant level in the C. endivia and the Belgian chicories and higher levels in
the red C. intybus vegetables and the hybrid vegetable. All juice behaviors in the linoleic acid-â-
carotene system indicate that they also contain a thermally unstable component, which in a cold
medium promptly promoted and accelerated linoleic acid peroxidation, therefore masking the presence
of any thermally stable antiperoxyl radical components. The presence of these components, which
efficiently protect linoleic acid from peroxidation, can be singled out only after inactivation by heating,
or separation by dialysis, of the pro-oxidant components. Dialysis fractions showed that the prooxidant
component has MW > 50000 Da and that the juices contain a number of antioxidant
components which contribute to their antiradical activity
Anti- and pro-oxidant activity of water soluble compounds in Cichorium intybus var. silvestre (Treviso red chicory)
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