Developing a gelatin-stabilized nanosilver particle/agar hydrogel for visually monitoring the freshness of braised chicken meat

Abstract This study developed a novel gelatin-stabilized nano-silver particle/agar hydrogel (AgNP) and explored the color rendering mechanism of AgNP hydrogel in monitoring the freshness of braised chicken. The results showed that the color of AgNP hydrogels shifted from brown to gray-white within 3 days of storage of braised chicken and that AgNP hydrogels extended the shelf-life of unpackaged braised chicken meat from 4 d to 6 d at 4°C (P < 0.05). The results of circular dichroism (CD), particle size, zeta potential, and UV indicated that the Cl⁻ on the surface of braised chicken could react with Ag⁺ on the surface of AgNP, resulting in the formation of AgCl particles during storage. These AgCl particles were further transformed into black Ag₂S particles, causing the visual color shift of the AgNP to gray-white. Overall, AgNP could provide a new method for the freshness assessment of cooked meat products.