A gelatin-stabilized nanosilver particle for visual freshness monitoring of braised chicken meat

This study developed a novel gelatin-stabilized nano-silver particle/agar hydrogel (AgNP hydrogel) and investigated its color rendering mechanism for monitoring the freshness of braised chicken. The results showed that the color of AgNP hydrogel shifted from brown to gray-white within 3 days of storage of braised chicken, and its application 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 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 subsequently transformed into black Ag₂S particles, causing the visual color shift of AgNP to gray-white. Overall, the AgNP hydrogel could provide a new method for the freshness assessment of cooked meat products.