Condensed Tannin Accumulation and Composition in Skin of Shiraz and Cabernet Sauvignon Grapes during Berry Development

Development of Tannins and Methoxypyrazines in Grape Skins, Seeds, and Stems of Two Pinot Noir Clones during Ripening

“…While the skin extension subunit composition was primarily made up of epicatechin (62%) and epigallocatechin (33%) with lower proportions of catechin (3%) and epicatechin gallate (2%) at harvest, the compositional differences during berry development were not discussed in this study. Previous studies on other red grape varieties, including Shiraz and Cabernet Sauvignon, have also found that epicatechin is the primary extension subunit present in seeds, while both epicatechin and epigallocatechin in skins. ,, Studies on the changes in tannin concentration and composition in Pinot noir skins and seeds during berry development are very limited, which is important for better tannin extraction management in Pinot noir production.…”

“…Previous studies have investigated tannin concentration and composition changes in grapes during berry development. − Generally, tannin content in berries increases toward véraison, followed by a decreasing trend toward harvest. However, some studies have also reported no decrease, fluctuations, or even an overall increase in tannin content from véraison to harvest, likely due to the differences in geographical location, variety, and the tannin extraction and analysis protocols used in these studies. ,, The size and composition of tannins have been found to vary significantly among different grape tissues. In general, the mean degree of polymerization (mDP) of seed tannins is lower than skin tannins, − with the mDP of skin tannins ranging from 20.1 to 42 and seed tannins ranging from 8.5 to 9.4 during Pinot noir berry ripening .…”

“…Previous studies on other red grape varieties, including Shiraz and Cabernet Sauvignon, have also found that epicatechin is the primary extension subunit present in seeds, while both epicatechin and epigallocatechin in skins. 12,13,20 Studies on the changes in tannin concentration and composition in Pinot noir skins and seeds during berry development are very limited, which is important for better tannin extraction management in Pinot noir production. Jordaõ et al 21 investigated the evolution of proanthocyanidins in the stems of Castelaõ Franceŝ, Touriga Francesa, and Viosinho in Portugal during berry development.…”

Evolution of Seed-Soluble and Insoluble Tannins during Grape Berry Maturation

“…The decrease in CT content after véraison is speculated to be due to the formation of oxidative cross-linking products, which strongly bind with the proteins and polysaccharides of cell walls, thus reducing the extractable rate of CT [ 17 ]. However, some studies also indicate no significant evolution of CT content in the seeds during the ripening stage of grapes [ 18 , 19 , 20 ]. The different conclusions obtained may be related to the grape varieties and the solvents or methods used for CT extraction, as well as the influence of abiotic factors such as solar radiation, temperature, water availability, altitude, ripening process, and cultivation practices [ 5 ].…”

Iowa wine: Consumer perception, typical composition, and evaluation of strategies to remediate low red wine tannin

“…This is associated with an increase in the mDP from 4.5 in green berries to 27 in red berries. The mDP of skins has been calculated to be about 33 in Merlot and 31 in red Shiraz berries [48,49]. Recently, a crown procyanidin tetramer composed of (−)-epicatechin has been identified in wine, and only in skins of Cabernet sauvignon, and was absent from seeds and the bunch stem [40].…”