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 language | English |
---|---|
Pages (from-to) | 4345-4352 |
Number of pages | 8 |
Journal | Journal of Agricultural and Food Chemistry |
Volume | 63 |
Issue number | 17 |
DOIs | |
Publication status | Published - 6 May 2015 |
Keywords
- hydrogen bonding
- hydrophobic interactions
- ITC
- polyproline
- wine tannin