Smart thermoplastic starch films with dual functionality: Quality preservation of tomatoes and spoilage detection in...

Smart food packaging offers a means to reduce food waste by combining active protection with real-time spoilage monitoring. In this study, thermoplastic starch (TPS) films were developed using Aronia melanocarpa extract (AE) as a dual-function active and colorimetric agent and cellulose nanocrystals (CNCs) as reinforcing fillers. Physicochemical characterization showed that the film containing 0.1 wt% CNC (AE/CNC10/TPS) provided the best balance of barrier, structural, and mechanical properties. The films exhibited strong antioxidant activity (∼95 % ABTS, ∼88 % DPPH), selective antibacterial efficacy against E. coli, and anthocyanin release governed by Fickian diffusion during the first 8 h, with release rates strongly dependent on food simulant polarity. When applied to cherry tomatoes, AE/CNC10/TPS films effectively reduced weight loss, maintained firmness, and delayed compositional changes over 20 days of storage at 23 °C. As intelligent indicators, the films showed reproducible ammonia-triggered color changes correlating with chicken spoilage. Analytical calibration revealed a detection limit of 13.3 mg N/100 g, below the poultry spoilage threshold, and a quantification limit of 44.2 mg N/100 g, with improved reproducibility above threshold levels. These results confirm that AE/CNC/TPS films function as fully bio-based, dual-purpose packaging capable of both preserving food quality and providing reliable early-warning spoilage detection.