Definition - What does Ellagitannins mean?
Ellagitannins are included in the large classification of hydrolyzable tannins. These are tannins, when heated with sulfuric or hydrochloric acids, yield ellagic or gallic acids. The galloyl groups of ellagitannins are linked with C-C (carbon-carbon) bonds containing numbers of hexahydroxydiphenoyl units (HHDP). They also contain sanguisorboyl and galloyl units which are bound to sugar moiety. Ellagitannins are a common occurrence in forty-six different foods, raspberries being a major source of them.
WineFrog explains Ellagitannins
Pertaining to the wine industry, ellagitannins are naturally occurring in oak used in the aging of wine. Levels of the ellagitannins will vary depending on the type of oak used. As tannin is a natural antioxidant preventing the premature aging of wine, ellagitannins from oak also play a major role against the oxidation of wine. They are components from the barrel which are imparted into (mainly) red wine when it is aged in oak. These ellagitannins have the ability to absorb dissolved oxygen. Regarding the organoleptic aspect of wine, they give structure to the wine and have the ability to balance with fruit tannin in the overall texture and mouth-feel of wine.