Bioactive and Chemical Characterization of Grape Pomace from Different Grape Varieties for Its Valorization as a Functional Ingredient in Gummy Candies

Grape pomace (GP), a major wine industry residue, contains substantial amounts of phenolic bioactive compounds whose valorization potential remains underexploited. In this study, pomaces from the Syrah, Malbec, Cabernet Sauvignon, Tempranillo, Nebbiolo-Sangiovese (blend), Cabernet Franc, Merlot, and Ensamble varieties were characterized in terms of total phenolic content (TPC), flavonoids, anthocyanins, tannins, and antioxidant capacity. Grape pomace flour (GPF) was obtained by drying, milling, and sieving (<250 µm) GP at 60 °C, and its functional properties were compared with GP and two commercial pomace flours (H1 and H2). The GPFs had a TPC of 3.48–12.06 mg gallic acid equivalents g−1 dry basis (d.b.), flavonoid content of 11.78–71.65 mg quercetin equivalents g−1 d.b., anthocyanin content of 41.46–291.85 mg cyanidin-3-glucoside equivalents g−1 d.b., tannin content of 18.85–45.98 mg (+)-catechin equivalents g−1 d.b., and antioxidant capacity of 304.2–768.3 μmol Trolox equivalents g−1 d.b. The Malbec variety exhibited the best bioactive profile and was incorporated into a gelatin-based gummy matrix. Color and bioactive compound stability were measured over 30 days of storage at 40 °C and compared with a commercial flour (H1). The valorization of GP through drying and milling is a viable strategy for obtaining a flour with potential as a functional ingredient due to its bioactive composition and as a natural colorant in the food industry.