Encapsulation of bioactive compounds from byproducts of two species of passionflowers: evaluation of the physicochemical properties and controlled release in a gastrointestinal model

This study aimed to evaluate the release of active components with antioxidant and antihypertensive capacity from encapsulated extracts of the peel and seeds of Gulupa (Passiflora edulis f. edulis) and Cholupa (Passiflora maliformis) in an in vitro gastrointestinal digestion model. Microencapsulated extracts were prepared with enzymatically modified rice starch as the encapsulating material and ethanol extracts of seeds and peel of P. edulis f. edulis and P. maliformis as encapsulated material. Microcapsule characterization was performed by scanning electron microscopy with values of 4.54–5.13 μm and ξ potential values of -6.34 mV and -6.66 mV. Dynamic light scattering (DLS) analysis was conducted with polydispersion values from 1.33 to 1.51, and dispersion stability analysis was also conducted. The total phenol content and antioxidant activities (ABTS, DPPH, and FRAP) and ACE inhibitory activity (in vitro antihypertensive activity) were evaluated after each stage of digestion, with values greater than 80% of activity before gastrointestinal transit and with values greater than 55% activity after the end of gastrointestinal transit. Gastrointestinal evaluation of the encapsulated extracts was performed with an ex vivo model using pig intestines and simulating the conditions of digestion in three phases: the gastric (pH 2.0 with 1.0 M HCl +0.5 g/L pepsin), enteric (pH 8.0 with Krebs solution +1.0 mL/L bile) and final enteric (pH 7.5 Krebs solution only) phases. The microencapsulation of passionflower extracts showed good behavior against changes in pH and enzymatic activities throughout digestion, thus promoting a controlled release and targeted delivery of bioactive compounds, undergoing a paracellular mechanism through the intestinal barrier to preserve the antioxidant activity and ACE inhibitory that was shown by the extracts before encapsulation of the material.