Biodegradable and active materials based on PHBV for sustainable food packaging

Abstract

Polyhydroxyalkanoates (PHAs) are sustainable biopolymers that offer biodegradability, biocompatibility, and a renewable origin, making them a promising alternative to petrochemical plastics in food packaging. Their environmental benefits, combined with their functional versatility, make them ideal candidates to replace conventional materials that contribute to plastic pollution. Among them, poly(3-hydroxybutyrate) (PHB) and its copolymer with hydroxyvalerate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), are the most studied PHAs for food packaging applications. Both have excellent water vapour and oxygen barrier properties, and are biodegradable under aerobic and anaerobic conditions in different ecosystems. However, their high crystallinity and low melt viscosity make them difficult to process for packaging applications, so different strategies have been used to improve their properties. Various studies have analysed the potential of PHBs to obtain active packaging materials to extend the shelf life of food by incorporating different bioactive compounds with antioxidant and/or antimicrobial properties. Some of the bioactive compounds have been extracted from natural sources, such as plants and agri-food waste, thus fulfilling two objectives: waste recovery and the use of natural preservatives. This comprehensive review provides an analysis of recent studies on PHB-based active materials for food packaging systems and the impact of incorporated bioactive compounds on material properties, their ability to extend the shelf life of certain foods, and the biodegradation pattern of the materials. It compiles information on how active compounds provide enhanced functionality to PHB materials, such as antioxidant and/or antimicrobial activity, while other characteristics relevant to food packaging, such as mechanical and barrier performance, may also be affected.