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While keeping wines on the fine lees the composition of nitrogen-containing substances, including the amino acid concentration, changes as a result of the autolysis of yeasts. During the course of former experiments, it was proven that yeasts were able to reduce the polyphenolic composition of wines. As part of the research for the present publication, the change of polyphenolic content in ‘Chardonnay’ wines kept on the lees was analysed. In addition the quantity of tyrosol, required for the forming of simple phenolics, was examined. The results proved that yeasts reduced the quantity of polyphenolics. In addition, due to the increased amino acid concentration, yeasts reduced the quantity of tyrosol that is derived from the amino acid called tyrosine.

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Orvosi Hetilap
Authors: Attila Hegedűs, Nóra Papp, Anna Blázovics, and Éva Stefanovitsné Bányai

RE. Anthocyanin and polyphenolic composition of fresh and processed cherries. J Food Sci. 2004; 69: FCT73–FCT83. 22 Piccolella S, Fiorentino A, Pacifico S, et al. Antioxidant

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Previous reports highlighted the onion solid wastes as abundant, residual material that might contain a significant load of antioxidant polyphenols. Although there have been studies pertaining to polyphenol recovery from onion wastes, the effect of temperature has not been adequately addressed. In this line, this study was undertaken with the aim of establishing a correlation between the extraction yield in total polyphenols and the extraction temperature, using acidified aqueous ethanol as the solvent system. Extraction of polyphenols from onion solid wastes was found to obey 2nd-order kinetics. On such a basis, the yield in total polyphenols at saturation could be very effectively determined and correlated with temperature using non-linear regression. The results indicated that the extraction yield at saturation is highly correlated with temperature, following a quadratic function. The extract obtained at optimal temperature (40 °C) had a total polyphenol yield of 21.10 mg gallic acid equivalents per gram of dry weight, and it was further analysed by liquid chromatography-mass spectroscopy to characterise its major constituents. The polyphenols detected were quercetin glucosides, as well as quercetin oxidation derivatives, including certain degradation products and dimers. The outcome of this study outlined that temperatures above 40 °C are rather not favourable for polyphenol extraction from onion solid wastes, as suggested by the model established through kinetics. The extract obtained under optimal conditions contained peculiar polyphenolic composition, not encountered in any other food processing residue.

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change of polyphenolic composition and tyrosol content of the wine as an effect of sur lie method . Acta Alimentaria, , 40 (Suppl.), 79 – 90 . OIV ( 2016 ): International Organization of Vine and Wine: Methods

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Acta Biologica Hungarica
Authors: Bettina Eck-Varanka, Nóra Kováts, Katalin Hubai, Gábor Paulovits, Árpád Ferincz, and Eszter Horváth

polyphenolic composition of purple loosestrife (Lythrum salicaria) . Z. Naturforsch. C 56 , 13 – 20 . 17. Tunalier , Z. , Koşar , M. , Küpeli , E. , Çaliş , I. , Başer , K

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.C. & Troncoso, A. (2004): Antioxidant activity of wines and relation with their polyphenolic composition. Anal. chim. Acta , 513 (1), 113–118. Troncoso A. Antioxidant activity of

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Acta Alimentaria
Authors: LJ. Glavaš-Obrovac, T. Opačak, V. Bareš, D. Šubarić, J. Babić, V. Ilakovac, and I. Karner

): Antioxidant activity of wines and relation with their polyphenolic composition. Anal. chim. Acta , 513 , 113-118. Antioxidant activity of wines and relation with their polyphenolic composition Anal

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Chaovanalikit, A., Wrolstad, R. E. (2004) Anthocyanin and polyphenolic composition of fresh and processed cherries. Journal of Food Science 69: 73–83. Wrolstad R. E. Anthocyanin and

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. , 24 , 148 – 153 . P érez -E steve , É. , S áłala , A. , B arat , J.M. , S tępniowska , A. , L ópez -G alarza , S. & N urzyńska -W ierdak , R. ( 2018 ): Polyphenolic

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Makris, D.P., Psarra, E., Kallithraka, S. & Kefalas, P. (2003): The effect of polyphenolic composition as related to antioxidant capacity in white wines. Fd Res. int. , 36 , 805–814. Kefalas P

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