1 research outputs found
Comparison of Extraction Protocols To Determine Differences in Wine-Extractable Tannin and Anthocyanin in <i>Vitis vinifera</i> L. cv. Shiraz and Cabernet Sauvignon Grapes
Cabernet
Sauvignon and Shiraz grapes were sourced from different
regions within Australia, and microvinified with a skin contact period
of 6 days. Grape samples were extracted using two protocols: a 15%
v/v ethanol, 10 g/L tartaric acid extract of gently crushed berries
(wine-like, WL) and a 50% v/v ethanol, pH 2 extract of grape berry
homogenate. It was found that in WL extracts, grape tannin and anthocyanin
concentrations were strongly related to wine tannin, anthocyanin and
color density achieved during the skin contact period. No relationship
was observed for grape tannin concentration analyzed in homogenate
extracts and wine tannin, but a strong, positive relationship was
found for anthocyanin concentration. When the data obtained from homogenate
extraction was treated separately by grape variety, a stronger relationship
between grape and wine tannin concentration was observed. Tannin compositional
analysis in wines indicated that higher tannin concentrations were
due to the extraction of tannin of higher molecular mass during fermentation,
most likely from grape skins