1,721,476 research outputs found
Fragole e piccoli frutti come principali fonti alimentari di ellagitannini nella dieta occidentale
Full text linkGli ellagitannini sono una classe di polifenoli naturali presenti in un numero ristretto di alimenti, tra i quali spiccano fragole, lamponi e more. Questi frutti sono caratterizzati dalla presenza di fito-complessi naturali contenenti svariate strutture oligomeriche, la cui composizione può essere affrontata con un approccio combinato che richiede esperimenti mirati di cromatografia liquida ad alta prestazione analitica e preparativa, spettrometria di massa, spettroscopia UV e NMR.
La complessità di questa classe di sostanze fa sì che a oggi si abbia ancora un’incompleta comprensione della loro esatta presenza negli alimenti, che è stata meglio chiarita solo di recente nel caso dei piccoli frutti [1-4]. All’opposto è ampiamente studiata per alcuni altri alimenti come la melagrana, di cui costituiscono il principale principio attivo. La singola molecola più presente nella dieta occidentale è probabilmente l’agrimoniin, un principio attivo che rappresenta il principale ellagitannino della fragola e della fragolina di bosco [3].
Il destino metabolico degli ellagitannini nell'intestino segue un meccanismo comune che passa attraverso la loro depolimerizzazione con formazione degli intermedi principali, le urolitine, composti specifici di questa classe di polifenoli. La precisa caratterizzazione dell’esatta struttura degli ellagitannini nei frutti permette oggi di studiare in maniera più precisa le loro proprietà salutistiche, tra le quali è particolarmente interessante la loro attività anti-infiammatoria a livello gastrico, che ne ha recentemente fatto suggerire un loro potenziale uso in regimi dietetici contro l’ulcera peptica. [5]
Riferimenti bibliografici
(1) Vrhovsek, U, et al. European Food Research and Technology 2008, 226, 817-824.
(2) Gasperotti, M, et al. J. Agric. Food Chem. 2010, 58, 4602−4616.
(3) Vrhovsek, U, et al. J. Agric.Food Chem. 2012, 60, 2507−2516.
(4) Gasperotti, M, et al. J. Agric. Food Chem. 2013, in press, dx.doi.org/10.1021/jf402706h
(5) Sangiovanni, E, et al. PLoS One 2013, 8, e71762
Kinetic investigations of the Gewürztraminer volatile organic compounds and color at different temperatures and pHs
No full textGewürztraminer is a well-known wine famous for its aroma profile, which is characterized by rose petals, cloves, lychees, and other tropical fruit notes. It is cultivated worldwide, including the Trentino Alto Adige region located in northern Italy, especially in the Tramin zone, and it has long been studied trying to understand what the most characterizing volatile aroma components are [1-4]. The terpenes (geraniol, cis rose oxide, citronellol, and linalool) are between the major responsible for the characteristic floral aroma of this cultivar’s grapes and wines. Throughout the winemaking and storage, acid-catalysed rearrangements take place producing cyclic and hydroxylated forms of the above terpenes, which generally have minor perception thresholds and so the wine’s floral aroma character decreases [5]. It has been demonstrated that the temperature and pH strongly influence these reactions, however their kinetics are not studied in detail. The first aim of this work was to develop and validate a fast, modern, sensitive, selective, robust, and comprehensive protocol for the quantification of primary, secondary, and tertiary wine volatile compounds by using solid-phase extraction (SPE) cartridges for the sample preparation and a fast GC-MS/MS for analysis [1]. Second aim was to apply this protocol and study the kinetics of the reactions occurring on the Gewürztraminer wine volatile compounds during its storage at various temperatures and pHs. In parallel also the colour of the wines was monitored by using the CIELAB method. The produced method gave us the possibility to measure 64 aroma compounds, with big importance in wine science, by using fewer organic solvents, having short chromatographic run, and increasing specificity and sensitivity due to the MRM MS-mode used. The results of the second part of the study, demonstrated the behaviour of volatile aroma compounds, with their absolute concentrations. The investigated reactions included the degradation of the linear terpenes (linalool, geraniol, nerol, etc), the ethyl esters of fatty acids and volatile phenols on the one hand; and the formation of the cyclic terpenes (1,4-cineole, 1,8-cineole, terpineol, etc), the norisoprenoids (e.g. TDN and safranal) and the diprotic organic acids esters on the other hand. In conclusion, we developed a modern protocol for the analysis of the wine aroma compounds and we underlined some key characteristics that a winemaker should take in consideration in the Gewürztraminer production and aging/storage. References 1. Carlin, S.; Lotti, C.; Correggi, L.; Mattivi, F.; Arapitsas, P.; Vrhovsek, U. “Measurement of the effect of accelerated aging on the aromatic compounds of Gewürztraminer and Teroldego wines, using a new SPE-GC-MS /MS protocol” Metabolites 2022, 12(2), 180. 2. Versini, G. Sull’aroma Del Vino “Traminer Aromatico” o “Gewürztraminer.” VIGNEVINI 1985, 12, 57–65. 3. Guth, H. Identification of Character Impact Odorants of Different White Wine Varieties. J. Agric. Food Chem. 1997, 45, 3022–3026. 4. Román, T.; Tonidandel, T.; Larcher, R.; Celotti, E.; Nicolini, G. Importance of Polyfunctional Thiols on Semi-Industrial Gewürztraminer Wines and the Correlation to Technological Treatments. Eur. Food Res. Technol. 2018, 244, 379–386. 5. Slaghenaufi, D.; Ugliano, M. “Norisoprenoids, Sesquiterpenes and Terpenoids Content of Valpolicella Wines During Aging: Investigating Aroma Potential in Relationship to Evolution of Tobacco and Balsamic Aroma in Aged Wine.” Front. Chem. 2018, 6
Insight on Lugana flavor with a new LC-MS method for the detection of polyfunctional thiols
No full textThe analysis of important aroma compounds, such as polyfunctional thiols, requires a reliable and straightforward method. Despite advances in odorant detection, each method currently involves lengthy and complex sample preparation. In this paper, we present a novel high-throughput method that includes derivatization with ebselen, SPE purification, and LC-MS analysis for the quantification of 15 thiols with enological relevance, as well as its comparison with a recently developed QuEChERS-based method. Furthermore, the analysis of 43 Lugana wines was conducted to gain insight into the thiolic composition of this typical Italian wine characterized by tropical flavors and to demonstrate the efficacy of this fast, reliable, and environmentally friendly metho
Exceptionally fast uptake and metabolism of cyanidin 3-glucoside by rat kidneys and liver.
No full textTo asses the hypothesis that anthocyanins are rapidly taken up from the blood into tissues, where they accumulate up to their bioactivity threshold, an intravenous dose of cyanidin 3-glucoside (1) was administered to anaesthetized rats. Cyanidin 3-glucoside (1) and its metabolites were analyzed in the plasma, kidneys, liver, urine, and bile, using last-generation mass spectrometry. Compound 1 was found to rapidly disappear from plasma (t/2=0.36 min). As soon as 15 s after its administration, both 1 and its methylation product, peonidin 3-glucoside (2), were detected in the plasma, kidneys, and liver. At 1 min, both 1 and 2 had almost disappeared from the plasma, but attained their peak concentrations in the kidneys and in the liver. Compound 2 was rapidly excreted both in the bile and in the urine. Three additional methylated metabolites were detected in traces, namely, delphinidin 3-glucoside (3), petunidin 3-glucoside (4), and malvidin 3-glucoside (5). These data contribute to solving the paradox of the high bioactivity of anthocyanins in spite of their apparent low bioavailability
Studio sul contenuto in lipidi, polifenoli e carotenoidi in foglie di vite sottoposte a taglio meccanico.
Full text linkSolid-phase extraction followed by Gas Chromatography–Mass Spectrometry for revealing the effects of the application of bentonite, tannins, and their combination during fermentation in the production of white wine
Full text linkTo investigate the effects of the application of bentonite, tannins, and their combination in alcoholic fermentation, Malvazija istarska (Vitis vinifera L.) white grape must was treated with 95 g/L of bentonite, 25 g/L of a hydrolysable tannin preparation, while the third treatment received the aforementioned doses of both agents. Control grape must was fermented without bentonite and exogenous tannins. All of the produced wines were additionally fined after fermentation with doses of bentonite needed to achieve complete protein stability. Wines were analyzed both after fermentation and after additional bentonite fining. Standard physicochemical parameters were determined by the OIV methods, and phenols were analyzed by high-performance liquid chromatography with diode-array detection (HPLC-DAD), while the concentrations of free and bound volatile aroma compounds were obtained after solid-phase extraction (SPE) followed by gas chromatography–mass spectrometry (GC-MS). Bentonite and tannins in fermentation generally reduced the total dose of bentonite needed for complete stabilization. Treatments with bentonite slightly decreased the concentration of total dry extract, while tannins preserved total acidity. The negative effect of bentonite on flavonoids was more severe. Tannins in fermentation preserved more hydroxycinnamoyltartaric acids with respect to control wine, and this effect was additionally enhanced by bentonite. Volatile and bound aroma composition was affected by all the treatments, while the addition of tannins resulted in higher concentrations of several important odoriferous esters, such as ethyl hexanoate, ethyl decanoate, and hexyl acetate. Additional fining with bentonite to complete protein stabilization annulled some of the positive effects observed after fermentatio
Fast Access of Some Grape Pigments to the Brain
No full textAnthocyanins represent the main flavonoid pigments in red grape and wine, in red berries, and in many other fruits and vegetables and are widespread in the human diet. After ingestion, these complex, hydrophilic compounds quickly appear as intact molecules in the plasma. This study investigated their presence in the brain of anesthetized rats that received 8 mg/kg of body weight of a pure anthocyanin mixture extracted from Vitis vinifera grapes. The mixture was maintained in the stomach for 10 min. After this time, intact anthocyanins were detected by HPLC-DAD-MS not only in the plasma (176.4 +/- 50.5 ng/mL, mean +/- SEM) but also in the brain (192.2 +/- 57.5 ng/g). These results demonstrate for the first time that grape pigments can reach the mammalian brain within minutes from their introduction into the stomach
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