US Patent 5484594: Process for preparing grapeseed extracts enriched…

A process for the preparation of an extract enriched in procyanidol oligomers from Vitis vinifera grapeseeds, said extract containing less than 1.5% by weight of flavanolicmonomers, less than 1% by weight of (+)-catechin and between 2 and 7 procyanidol units which comprises the steps of: a) extracting said Vitis vinifera grapeseeds with an aqueous acetone or aqueous methanol solution until exhaustion of catechin derivatives to obtain an aqueous acetone or aqueous methanol solution; b) concentrating said aqueous acetone or aqueous methanol solution from step a) under vacuum to remove the acetone or methanol to obtain a precipitate containing fatty and tannic polymeric residues and a first aqueous solution; c) filtering said precipitate from the first aqueous solution from step b) to remove said precipitate containing the fatty and tannic polymeric residues from said first aqueous solution; d) subjecting said first aqueous solution from step c) to ultrafiltration on membranes of cut-off 100,000 to give a first permeate; e) subjecting said first permeate from step d) to ultrafiltration to remove most of the flavanolic monomers on membranes of cut-off 3,000 to 600 to obtain a second pe