Release of phenolics compounds from Rubus idaeus L. dried fruits and seeds during simulated in vitro digestion and their bio-activities

To evaluate the bio-availability of raspberries (Rubus idaeus L.), raspberry dried fruits (RDF) and seeds (RDS) were subjected to in vitro simulated digestion. In total, 2158.6 mg and 1904.7 mg GAE/100 g DM of phenolics could be released from RDF and RDS, respectively, after four in vitro digestion stages, including oral, gastric, small-intestine and large-intestine digestion. The phenolics were mostly released in the gastric digestion stage for RDF and in the small-intestine digestion stage for RIDS. The results include an analysis of ten major phenolic compounds, which showed that ellagic acid pentoside was the major compound released from RDF and RDS during gastric digestion, whereas ellagic acid was the primary compound released in small-intestine digestion. A significantly positive correlation existed between the observed bio-activities and the total phenolics/flavonoids released. Consequently, both raspberry fruits and seeds can be considered as raw materials of functional food enriched in natural antioxidants.