Eco-smart biopolymer films with Cassia auriculata gum and anthocyanins for pH-responsive fruit freshness monitoring

Synthesizing pH-sensitive films for real-time monitoring of freshness is essential for effective food quality assessment. In this study, pH-sensitive films were fabricated by incorporating Ixora coccinea anthocyanin (IC-ATH) into a κ-carrageenan/carboxymethyl cellulose (CA/CMC) matrix using solution casting, both with and without the inclusion of Cassia auriculata gum (CAG) to monitor the freshness of Fragaria ananassa (strawberry). The film properties, including thickness, moisture content, color, mechanical properties, swelling property, as well as pH and biodegradability were evaluated.The CAG film exhibited a thickness of 0.30 mm, a tensile strength of 15.50 MPa, and an elongation at break of 15%, all of which surpassed the corresponding values observed in the CA film.The films exhibited exceptional pH sensitivity, showing clear color transitions across the pH range of 2.0 to 11.0. The inclusion of CAG improved the film’s crystallinity, antioxidant properties and even the moisture content in them. Unwrapped strawberries (control) showed bacterial growth within 3 days and experienced 55% weight loss during storage. In contrast, strawberries wrapped with CA/CMC/IC films exhibited bacterial growth only after 5 days and showed a reduced weight loss of 43%. Notably, CAG/CMC/IC films further delayed bacterial growth until 7 days and minimized weight loss to 24%. This innovative approach underscores the potential of CAG/CMC/IC films as a reliable, eco-friendly solution for the real-time freshnessof Fragaria ananassa, marking significant advancements in smart packaging technology.