AbstractThe bioavailability of anthocyanins from raspberry extracts was assessed using an in vitro digestion procedure that mimics the physiochemical and biochemical changes that occur in the upper gastrointestinal tract (GIT). The total phenol content of the raspberry extract survived gastric digestion and was divided into the IN sample (represents the serum available material) and OUT sample (represents the material that remains in the GIT and passes through the colon). All anthocyanins also survived gastric digestion, but only ~5% entered the IN sample and ~70% were recovered from the IN and OUT samples. Codigestion of the raspberry extract with commonly combined foodstuffs such as bread, breakfast cereal, ice cream and cooked minced beef gave a different pattern. The total phenol content of the IN samples was slightly reduced by codigestion with ice cream or breakfast cereal, but unaffected by codigestion with bread or minced beef. In most cases, the phenol contents of the postgastric and OUT samples were reduced as compared with the expected values. However, the anthocyanin content of the IN samples was unaffected or increased by coincubation with the foodstuffs. This suggests that polyphenols transiently bind to food matrices during digestion, which protects the more labile anthocyanins from degradation, and they are free to diffuse into the IN sample. The anthocyanin composition of the bioavailable samples was monitored by liquid chromatography-mass spectrometry. All 8 anthocyanins previously identified in raspberry were detected in the extract and the postgastric samples at similar yields. All 8 anthocyanins were detected in the IN and OUT samples, but some such as cyanidin-3-O-glucoside was greatly reduced while pelargonidin-3-O-glucoside was apparently increased in abundance. These differences in stability and their importance for the bioavailability of anthocyanins are discussed.