PH-responsive collagen nanocomposite films reinforced by curcumin-loaded Laponite nanoplatelets for dynamic visualization of shrimp freshness

Abstract

Sustainable and intelligent packaging systems, utilizing biomass-derived matrix and bioactive indicators represent promising approaches for real-time detection and monitoring of freshness of food, as well as prolonging the shelf-life and improving the quality and safety of food products. Herein, we reported pH-responsive collagen nanocomposite films reinforced by curcumin-loaded Laponite nanoplatelets which could act as smart indicators for monitoring the freshness of shrimps. Caffeic acid, as a bio-based modifier, was covalently grafted onto the surfaces of the nanoplatelets loaded with curcumin. The collagen nanocomposite films were fabricated by the incorporation of functionalized nanoplatelets through all-aqueous casting-evaporation approach. The triple-helical structure of collagen molecules was stabilized by the functionalized nanoplatelets mainly through hydrogen bonding and electrostatic interactions with uniform distribution into the film matrix. Moreover, the resultant nanocomposite films not only demonstrated favorable hydrophobicity and water vapor barrier properties, but also exhibited effective antioxidant activity and anticipated color responsiveness to pH changes and NH3 presence. The consistent changes in color of the nanocomposite film with the shrimps following days of storage supported its feasibility and potential for monitoring the freshness of shrimps. Therefore, we envision that the developed collagen-based nanocomposite films showcase great potential in the application of sustainable and intelligent packaging system for dynamic visualization of seafood freshness.