Application of Residues from Block Freeze-Concentrated Yerba Mate (Ilex paraguariensis) Extract as Functional Agents in Smart Biopolymeric Systems Under a Circular Economy Perspective

Yerba mate (Ilex paraguariensis) is a widely consumed beverage recognized for its high antioxidant content and bioactive compounds with health-promoting properties. Concentrating yerba mate extracts represents a valuable opportunity for industrial applications, including food packaging. Block freeze-concentration is a promising technology for concentrating food solutions while preserving functional compounds. In this context, the use of biodegradable polymers combined with natural components derived from by-products aligns with circular economy principles. This study aimed to develop an active and intelligent biopolymer film using residues from the block freeze-concentration of yerba mate extract (ice fraction). The film was produced by the casting method. Block freeze-concentration was performed in three stages, and process efficiency was evaluated using ice fraction 3. The films were characterized for physical, mechanical, thermal, antioxidant (total phenolic content, DPPH, and ABTS), and intelligent properties, including pH-responsive color changes, thickness, biodegradability, barrier performance, molecular structure by FTIR spectroscopy, and morphology by scanning electron microscopy (SEM). The main results showed a total phenolic content of 1.01 ± 0.02 mg GAE g−1 of film, 2094 ± 5.00 µmol TE g−1 for DPPH, and 1610.00 ± 8.00 µmol TE g−1 for ABTS. Color changes observed at different pH levels (4, 7, 10, and 12) demonstrated the film’s potential for application in intelligent packaging as a freshness indicator. The film exhibited complete disintegration under soil burial conditions within 45 days. The film presented a water vapor permeability of (1.80 ± 0.01) × 10−7 g H2O·m−1·s−1·Pa−1 and an average thickness of 0.26 ± 0.03 mm. As a result, these findings indicate that products derived from block freeze-concentration residues of yerba mate extract can be effectively applied in sustainable food packaging systems, contributing to shelf-life extension through antioxidant preservation and intelligent functionality.