Phenolic acids in black raspberry and in the gastrointestinal tract of pigs following ingestion of black raspberry.

Black raspberries (BRB) contain high levels of polyphenols and have been demonstrated to be chemopreventive. In order to investigate the underlying mechanism and study the metabolism of anthocyanins, pigs were fed freeze-dried BRB powder or purified diet (control) and three segments of the gastrointestinal (GI) tract (small intestine, cecum, and colon; 4 h after feeding) were collected for analysis of phenolic acids. Protocatechuic acid was the major phenolic acid (8.