Fabrication of pH‐intelligent elephant foot yam starch/poly(vinyl alcohol) films using encapsulated dragon fruit peel extract for shrimp freshness monitoring

BACKGROUND: The growing interest in intelligent food packaging has stimulated the development of natural pigment-based indicators for real-time freshness monitoring. Dragon fruit peel extract (DFPE), which is rich in betalains, exhibits distinct pH-responsive color changes; however, its limited stability restricts its application in intelligent packaging systems. In this study, DFPE was encapsulated using maltodextrin through an ultrasound-assisted process and subsequently incorporated into modified elephant foot yam starch (EFYS)/poly(vinyl alcohol) (PVA) films to develop biodegradable intelligent packaging material for monitoring shrimp freshness. RESULTS: The incorporation of encapsulated DFPE into the EFYS/PVA films improved their physicochemical, mechanical, and antioxidant characteristics of the films. The films exhibited good water affinity properties, adequate stability, and excellent compatibility between the encapsulated extract and the polymeric matrix. The pH-dependent characteristics of betalains contributed to significant color changes over a broad pH range, while the antioxidant activity increased with increasing DFPE concentrations. During the storage of shrimp at room and refrigerated temperatures, the color changes depending on the concentration of the film showed significant correlation with commonly applied freshness parameters such as total volatile base nitrogen, pH, thiobarbituric acid reactive substances, and total phenolic content. CONCLUSION: Ultrasound-assisted encapsulation facilitated the successful incorporation of DFPE into EFYS/PVA films, resulting in biodegradable intelligent films with improved functional properties and freshness-indicating performance. The developed films exhibited reliable real-time monitoring of shrimp freshness and showed considerable potential for seafood quality assessment and intelligent packaging applications. © 2026 Society of Chemical Industry.