Identification and changes of flavonoids in Merlot and Cabernet Sauvignon wines. J Food Sci
Authors Wulf and Nagel are with the Dept. of Food Science & Technology, Washington State Univ., Pullman, WA 99164. Journal of Food Science
(Impact Factor: 1.7).
08/2006; 45(3):479 - 484. DOI: 10.1111/j.1365-2621.1980.tb04080.x
Twenty components of an ethyl acetate extract from Merlot and Cabernet Sauvignon wines were isolated by recycle preparative HPLC. A combination of paper chromatography, fluorescence behavior, gas chromatography, reaction with molybdate, reaction with vanillin/HCI, ultraviolet spectrometry and mass spectrometry was used to gain information about the identities of the isolated compounds. Seven of the isolated compounds were catechins, procyanidins or degradation products thereof. Three flavonol glycosides were isolated and one was characterized as an isorhamnetin-3-glycoside. Four compounds were isolated with identical molecular weights and an uncharacteristic blue reaction with vanillin/HCl. These components were interconvertable and thought to be cis-trans isomers of flavenes. The changes in these components during aging of Merlot and Cabernet Sauvignon wines are discussed.
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- "Among these phenolic substances, flavonoids, and in particular anthocyanins, are of interest because of their high occurrence in foods. The presence of hydroxycinnamic acids and flavonols in grapes is well documented (Wulf & Nagel, 1980). The flavonols are localized in the solid parts of the cluster. "
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ABSTRACT: Growing conditions appear to influence the nutritional composition of different types of fruit. Grape contains a large amount of phenolic compounds in the skin, pulp, and seeds. In this research work, a comparison of the phenolic composition and antioxidant activity between red grapes (Vitis vinifera) var “Monastrell” obtained from organic and conventional cultures has been studied. The identification and quantification of phenolic compounds (anthocyanins, flavonols, and hidroxycinnamic acids) have been realized by high pressure liquid chromatography (HPLC) and analysis of antioxidant activity using the DPPH radical. No differences were found in the total phenolic composition as well as in the antioxidant activity in both types of grapes (organic and conventional).Las condiciones de cultivo parecen influir en la composición nutricional de diferentes tipos de fruta. La uva contiene una gran cantidad de compuestos fenólicos en la piel, la pulpa y las semillas. En el presente trabajo se ha realizado la identificación y cuantificación de compuestos fenólicos (antocianos, derivados hidroxicinámicos y flavonoles) por cromatografía de alta presión (HPLC) y el análisis de la actividad antioxidante utilizando el radical DPPH en uva tinta de la variedad Monastell obtenida por técnicas de cultivo ecológico y tradicional. No se han encontrado diferencias en la composición fenólica total en ambos tipos de uva (ecológica y tradicional), así como tampoco en la actividad antioxidante de las mismas.
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- "In order to characterize the products of degradation of ANC owing to industrial treatment of juices, further experiments with NaHSO 3 (Somers & Evans, 1977; Wulf & Nagel, 1980; Glories, 1984; Azar et al., 1987) were attempted. NaHSO 3 allowed the degree of degradation of the pigments and of the quantity of polymers to be estimated by comparison of OD 520 before and after the action of an aqueous solution of NaHSO 3 (50% v/v) on the different juices FPJ, RJ and SJ. "
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ABSTRACT: Summary The degradation of anthocyanic pigments of fresh and industrial juices from blood oranges were studied during storage periods of a few days at −18 °C and 12 months at 4 °C in nitrogen. The change of anthocyanin pigments was followed by HPLC at 520 nm while the coloured polymeric pigments were fractionated by chromatography and characterized by their transformation indices and their reactivity with NaHSO3. The results show that the process of polymerization is accompanied by production of chemical indicators of sugar and ascorbic acid degradation (furfural and hydroxymethylfurfural). It seems that the resulting polymeric compounds have structures different from those of the compounds formed during wine processing. Reactions between anthocyanic pigments and the intermediates of degradation of sugar and ascorbic acid in an acidic environment are the main causes of formation of these polymers.
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- "grapes, mainly in the skin (Wulf and Nagel, 1980; Cheynier and Rigaud, 1986) in the monoglycoside form, with the sugar residue linked to the hydroxyl group mainly in position C-3 of the O-containing ring. "
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ABSTRACT: The recovery of high added-value products from waste plant material has been an important issue with economic relevance for the pharmaceutical and food industries. The recovery of antioxidants from wine industry by-products is of great importance in the nutraceutical field. The aim of this study was to identify the main flavonol glycosides, present in winemaking by-products from two white grape varieties: Arinto and Moscatel using liquid chromatography with diode array and electrochemical detection. Liquid chromatography with electrospray and atmospheric pressure chemical ionization, in negative and positive modes, were also used to characterize the structures of the compounds detected by means of MS 2 and MS 3 . In the by-products analysed quercetin-3-glucoside and quercetin-3-glucuronide were identified as well as kaempferol-3-glucoside. By-products from Arinto variety showed higher levels of quercetin glycosides and kaempferol-3-glucoside than the by-products of Moscatel variety.
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