Polysaccharide-based pH-responsive intelligent halochromic food packaging materials: A review

Abstract

The pH-responsive intelligent food packaging materials change color in response to pH variations cuased by food spoilage and the release of microbial metabolites. Recently, polysaccharides have gained significant attention as potential matrices for such systems due to their numerous benefits over conventional fossil fuel-based packaging materials, including renewability, biodegradability, biocompatibility, relative abundance, film-forming ability, nontoxicity, and tailorable surface properties. Natural halochromic dyes have emerged as food freshness indicators (FFIs) due to their low cost, nontoxicity, eco-friendliness, rapid responsiveness, and ease of use. Numerous studies have been reported on the use of polysaccharides and natural halochromic dyes for fabricating pH-responsive polysaccharide packaging (PRPP) materials; however, the roles and mechanisms of action of these systems in monitoring food freshness have not been systematically analyzed. Therefore, the current study aims to fill a gap in an underexplored area of the literature by consolidating recent findings on PRPP materials and natural dyes for real-time detection of food freshness. This review comprehensively covers the structure and properties of polysaccharides and natural halochromic dyes, film fabrication techniques, mechanisms of food spoilage detection, and state-of-the-art intelligent food packaging applications of PRPP materials. Furthermore, this review discusses current regulations, safety considerations, challenges, and future perspectives of PRPP materials.