Encapsulation via the Vibrating Nozzle Technology as a Strategy for the Valorization of Pomegranate Peel Polyphenols

The aim of the present study was to investigate the bioactive composition of pomegranate peel and to produce a phenolic-rich extract for encapsulation using vibrating nozzle technology. Conventional heat- and advanced microwave-assisted extraction of phenolic compounds were investigated, and the extract with the highest phenolic content was used to perform encapsulation with alginate-based delivery solutions containing fava bean proteins, mucin, carboxymethyl cellulose, nutriose, and collagen hydrolysates. The formulated beads were characterized for their physico-chemical (morphology, size distribution parameters, and FT-IR spectra) and bioactive (encapsulation efficiency and simulated gastrointestinal digestion) properties. The highest yields of punicalin, punicalagin, and ellagic acid (9.40, 44.51, and 3.95 mg g−1 DM, respectively) were achieved by heat-assisted extraction at 80 °C. The addition of fava bean proteins and carboxymethyl cellulose to the alginate-based delivery solutions resulted in the highest encapsulation efficiency of total phenols (83.99 and 83.78%, respectively). However, the beads formulated with fava bean proteins were irregularly shaped, while those with carboxymethyl cellulose were predominantly spherical. All beads showed limited phenolic release under simulated gastric conditions, followed by enhanced release in the intestinal phase. Overall, the obtained results indicate that encapsulation efficiency was governed by the combined effects of rheological parameters, bead morphology, and molecular interactions, highlighting the importance of a multi-parameter design approach in the development of effective delivery systems.