Patent ID: 8257756

Claim:
A black soybean hull extract (BSHE) comprising components having a molecular weight less than 10000 Da, wherein the BSHE contains 10-45% cyanidin, 10-25% catechin, and 40-80% oligomer proanthocyanidin (OPC), and the total content of polyphenol is over 60%, wherein the BSHE is obtained by: (1) extracting crushed black soybean hull with an aqueous solution containing 0.05-0.2% of cellulase or pectinase as a solvent and filtering the extracted solution to obtain a filtration solution; (2) filtering the filtration solution with an ultrafiltration membrane to obtain an ultrafiltration filtrate, wherein the molecular weight cut-off of the ultrafiltration membrane is 8000-10000 Da; (3) absorbing the ultrafiltration filtrate with an absorbing resin or ion exchange resin and eluting the same with 40-95% ethanol to obtain a purified extract solution; (4) condensing the purified extract solution under vacuum to obtain a condensed solution; and (5) spray-drying the condensed solution to obtain the BSHE.