Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Mulberry extract/soluble soybean polysaccharide composite films integrate antioxidant activity and UV-blocking performance, while enabling ammonia-responsive colorimetric changes for visual monitoring of meat freshness.

ABSTRACT
Intelligent food packaging materials have attracted increasing attention due to their ability to indicate food freshness during storage. However, the development of soluble soybean polysaccharide (SSPS)-based systems for colorimetric freshness assessment remains limited. In this study, active and intelligent composite films were fabricated by incorporating mulberry extract (ME) into SSPS matrices. The incorporation of ME improved film flexibility but reduced tensile strength, with the elongation at break increasing from 13.92% to 42.33% and the tensile strength decreasing from 19.42 to 6.49 MPa. Antioxidant activity was enhanced, with the ABTS radical scavenging activity reaching 68.5% at the highest ME content. The addition of ME to the SSPS film significantly enhanced its UV-blocking efficiency while maintaining visible light transparency. The SSPS/ME films exhibited rapid colorimetric response (from dark red to yellow-brown) to ammonia vapor, showing their potential as pH-sensitive visual indicators for monitoring food freshness. Application studies on chicken breast preservation indicated that the SSPS/ME films effectively monitored meat quality during storage through distinct color changes, with the color parameter a* value decreasing markedly from 41.3 to 26.1 between Days 5 and 9. The results suggest that the SSPS/ME films are promising for real-time spoilage monitoring in meat products.