Ethanol Concentration Influences the Mechanisms of Wine Tannin Interactions with Poly(l-proline) in Model Wine

Jacqui McRae, Zyta Ziora, Stella Kassara, Matthew Cooper, Paul Smith

    Research output: Contribution to journalArticle

    28 Citations (Scopus)

    Abstract

    Changes in ethanol concentration influence red wine astringency, and yet the effect of ethanol on wine tannin-salivary protein interactions is not well understood. Isothermal titration calorimetry (ITC) was used to measure the binding strength between the model salivary protein, poly(l-proline) (PLP) and a range of wine tannins (tannin fractions from a 3- and a 7-year old Cabernet Sauvignon wine) across different ethanol concentrations (5, 10, 15, and 40% v/v). Tannin-PLP interactions were stronger at 5% ethanol than at 40% ethanol. The mechanism of interaction changed for most tannin samples across the wine-like ethanol range (10-15%) from a combination of hydrophobic and hydrogen binding at 10% ethanol to only hydrogen binding at 15% ethanol. These results indicate that ethanol concentration can influence the mechanisms of wine tannin-protein interactions and that the previously reported decrease in wine astringency with increasing alcohol may, in part, relate to a decrease tannin-protein interaction strength.

    Original languageEnglish
    Pages (from-to)4345-4352
    Number of pages8
    JournalJournal of Agricultural and Food Chemistry
    Volume63
    Issue number17
    DOIs
    Publication statusPublished - 6 May 2015

    Keywords

    • hydrogen bonding
    • hydrophobic interactions
    • ITC
    • polyproline
    • wine tannin

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