Determination of the components of polyphenols in the ultrafine powder of grape seed

The components of polyphenols in the ultrafine powder of grape seeds were measured and analyzed.Catechin is not only the main component of monomeric phenols in the grape seed polyphenols,but also the important material constituting proanthocyanidin.So it is more accurate that the content of polyphenols is expressed as catechin equivalents in the Folin-Ciocalteu method.Gallic acid,catechin and epicatechin of three monomeric phenols was separated well,the improved HPLC method was full of accuracy and precision,suitable for the determination of the three monomeric phenols in the ultrafine powder of grape seeds.The results showed that the contents of polyphenols expressed as catechin equivalents and the three monomeric phenols in the ultrafine powder of grape seed were 10.9% and 1.21%,respectively.The content of proanthocyanidin was 9.7% represented by the difference between amount of polyphenols and the three monomeric phenols.