COMPARATIVE FLAVAN-3-OL COMPOSITION OF SEEDS FROM DIFFERENT GRAPE VARIETIES

The flavanol composition of the seeds of 17 varieties of grape cultiva ted in the main wine-producing areas of Castilla-Leon (Spain) was stud ied. Twenty-seven different flavan-3-ols of procyanidin type were foun d, but no prodelphinidins were detected. Minor amounts of four hydroly zable tannins were also present in the seed extracts of most of the gr apes analyzed. All the varieties contained galloyled flavanols, such t hat their presence could be considered characteristic of the grape see d composition. Some proposals concerning the biosynthesis of flavan-3- ol in the grape seed are also advanced taking into account the compoun ds found.