Pectin/zinc alginate films containing anthocyanins from dragon fruit peel as intelligent pH indicators for shrimp freshness monitor

Abstract

The novel incorporation of dragon fruit peel extract (DE), rich in anthocyanins, Zn2+ (from Zinc Alginate) and pectin was applied to create active and intelligent food packaging composite films. These films were characterized for their microstructure and properties. Various levels of anthocyanin extracts (1 %, 3 %, and 5 %) were evaluated for their impact on the films' physical and functional properties, incorporating microstructure, mechanical strength, barrier properties, pH sensitivity, and bacteriostatic effectiveness. The films exhibited a significant antibacterial rate of up to 99.99 % against common foodborne pathogens, enhanced flame retardancy with an enhancement of 32.7 %, and a broad pH sensitivity range, indicating their adaptability to various conditions. The results demonstrated that the prepared indicator film achieved a 50 % reduction in water vapor permeability. Additionally, the mechanical properties were enhanced, with only a slight decrease of 12.2 % in tensile strength and 14.0 % in elongation at break. In tests monitoring shrimp freshness, pectin/ZA/DE films showed notable color changes correlating with shrimp quality. These specific values highlight the pectin/ZA/DE films' potential for real-world applications, suggesting that they have potential applications as smart packaging materials in the food industry.