Blackcurrant (R. nigrum) Pomace Extract-Loaded Hydrogels: A Sustainable Alginate–Inulin Matrix for Polyphenol Delivery

Blackcurrant (Ribes nigrum) is rich in polyphenols and is known for its antioxidant and anti-inflammatory properties, yet its processing byproducts (pomace) remain underutilized. This study aimed to develop and characterize R. nigrum pomace extract-loaded alginate–inulin hydrogel for potential topical application, thus promoting the valorization of R. nigrum pomace extract. Comparative extract analysis demonstrated that the pomace extract contained the highest levels of total polyphenols (71.0 mg GAE/g dried extract) and tannins (21.8%) and exhibited the most promising antibacterial activity (MIC 3.1–6.3 mg/mL), although its antiradical activity was relatively lower than that of juice and berry extracts. Furthermore, the obtained hydrogels were structurally stable and provided a gradual release of polyphenols at pH 5.5, with 80% released within 24 h. Incorporation of R. nigrum pomace extract increased the swelling of the hydrogels and improved viscoelastic recovery. Overall, the findings highlight the potential of R. nigrum pomace as a sustainable bioactive component in alginate–inulin hydrogel systems for potential topical applications in wound care.