Tannic acid as a multifunctional additive in polysaccharide and protein-based films for enhanced food preservation: A comprehensive review

Fossil-based polymers continue to dominate the market for single-use food packaging, despite increasing concerns about their sustainability. In response, natural and renewable polymers, such as proteins and polysaccharides, are gaining attention as potential alternatives due to their biodegradability and biocompatibility. However, their broader adoption is hindered by the need to improve their mechanical, barrier, and thermal properties. Tannic acid (TA) has emerged as a particularly effective additive for biopolymer-based films, offering strong antioxidant and antimicrobial properties. It also enhances mechanical and barrier characteristics through physical and/or covalent crosslinking. As a result, TA shows great potential as an additive for bioplastics, improving food packaging performance and extending product shelf life, while benefiting both the environment and the food industry. Despite the promising applications of TA, comprehensive reviews that focus on recent developments in its performance and bioactive properties remain limited. This review aims to highlight the effectiveness of TA as both an active ingredient and a crosslinking agent in various biopolymer films, offering valuable insights into its role in sustainable food packaging solutions by critically examining the latest advancements.