Hydroethanolic Extracts of Raspberry (Rubus idaeus) Pomace as Ingredients of Functional Foods: Characterization and Effect of Gastrointestinal Digestion.

The extract of powdered raspberry pomace was characterized in terms of its phenolic profile and antioxidant and antimicrobial activity. Kuromanin, chlorogenic acid, protocatechuic acid, and pelargonidin-3-O-glucoside were found to be the major phenolic compounds, while the antioxidant activity of the extract correlated positively with the total phenolic content (TPC), which was 472.9 ± 0.1 mg GAE/g dw. The extract also showed good antimicrobial activity against Gram-positive foodborne bacteria. More importantly, in vitro bioaccessibility of phenols from the raspberry pomace extract was 5-fold higher when the extract was incorporated into meringue cookies. Although the concentrations of anthocyanins, flavonoids, and tannins decreased after the oral, gastric, and intestinal phases of digestion, the TPC slightly increased as the compounds were released from the food matrix. The content of available phenolics was 4-fold lower in the case of a commercial raspberry colorant, demonstrating that the waste from raspberry pomace could serve as a valuable health-promoting ingredient for functional food formulations.