Physicochemical properties and gastrointestinal release of Chilean endemic berry extracts via biopolymer encapsulation

Polyphenolic extracts from native Chilean berries such as Berberis microphylla (calafate) and Luma chequen (chequén) exhibit high antioxidant capacity but low stability and bioavailability under environmental and gastrointestinal conditions. To overcome this limitation, this study evaluated alginate/carrageenan encapsulation as a strategy to preserve and enhance extracts stability and functionality. The methanolic extracts were characterized by HPLC-DAD and HPLC-QTOF-MS to identify the main phenolic components, while antioxidant activity was determined by the DPPH, ABTS, and FRAP assays. Total polyphenol content (TPC) and total anthocyanin content (TAC) were determined spectrophotometrically. The encapsulated systems were further analyzed by FTIR, SEM, and in vitro gastrointestinal digestion. L. chequen extracts showed the highest total phenolic content (31.65 ± 0.01 mg GAE/g) and reducing power (467.97 ± 1.09 μmol TE/g), while B. microphylla exhibited the highest anthocyanin content (424.07 ± 5.82 mg C3G/100 g) and achieved up to 94 % inhibition of the DPPH radical. Encapsulation in alginate/carrageenan microspheres improved thermal stability (T_max = 266 °C) and enabled controlled anthocyanin release under simulated digestive conditions, reaching 80–85 % intestinal release within 180 min. These findings demonstrate that alginate/carrageenan systems maintain phenolic and antioxidant integrity, supporting their potential application as natural functional ingredients in nutraceutical formulations.