Active bio-packaging with PHBHHx-ZnO bionanocomposites: advancing food safety and shelf-life

Food loss and waste remain major global challenges. Perishables like fish, fruits, and vegetables show the highest post-harvest losses. Conventional petroleum-based packaging offers limited preservation while adding long-term pollution, and recent assessments indicate that more than one billion tons of food were wasted in 2022, reinforcing the need for improved preservation strategies. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) films reinforced with ZnO nanoparticles provide flexibility, biodegradability, and reliable processing. ZnO increases mechanical stiffness and thermal stability, strengthens oxygen-barrier and antimicrobial functions, and delivers strong UV shielding. These combined properties define the active-preservation behavior of PHBHHx-ZnO films and support their relevance for chilled food systems. ZnO acts as a nucleating agent, with PHBHHx-ZnO films typically showing crystallinity in the 53–56% range without loss of flexibility. Studies with ZnO-enabled active films extend refrigerated shelf life. Storage periods of 6–8 days rise to 12–16 days in seafood models, with similar improvements for meat and dairy products. These gains arise from nanoparticle-polymer interactions that increase crystallinity, restrict polymer mobility, and stabilize film microstructures. PHBHHx-ZnO bionanocomposites offer a promising route toward safe, active, and sustainable packaging systems. This review outlines further directions, including migration-compliant ZnO placement, lower-impact ZnO preparation routes, and multifunctional designs aligned with more circular-economy goals.