Differences in the amount and structure of extractable skin and seed tannin amongst red grape varieties

• Numerous studies have reported the protective cardiovascular effects of polyphenolic antioxidants. It is estimated that flavonoids contribute approximately two-thirds of all the polyphenols ingested, whereas phenolic acids contribute the remaining one third. Red wine is a very rich source of flavonoids, particularly the class called flavanols. Other important sources of flavonoids are apples, berries, coffee and tea. (Let’s not confuse the very similar words: flavonoids, flavonols, and flavanols. The diagram below illustrates their relationship).