Anthocyanin-Cell Wall Interactions Effect on Tannin Extraction

The objectives of this proposal have been to do the following:

1) Perform extractions on white grape skins at 5 time points (13,17,20,22, and 25 °Brix) throughout maturity with varying levels of added anthocyanins.

• Extracted tannin will be analyzed for concentration, average molecular size, subunit composition, activity, and fraction extracted.
• Measure the levels of pectin methylation in the white grape skins

2) Conduct red-styled fermentations on Sauvignon blanc and Cabernet Sauvignon at 300 pounds per fermentation, with and without an anthocyanin addition. Measurements are the same as Objective 1.

The overall purpose of this proposal is to determine anthocyanins role on the extraction of procyanidin material due to interactions with cell wall material of grape skins. Activity to date has been the isolation and purification of color along with the sampling and extraction of skins with varying concentration of anthocyanins added. Furthermore, 300lb fermentations were conducted, in triplicate, under standard red wine making conditions with both Sauvignon Blanc and Cabernet Sauvignon with a 1.4% (v/v) addition of color concentrate.