Postbiotics in the food industry: applications, delivery systems, and future perspectives.

Postbiotics, defined as microbial metabolites, confer health and nutritional benefits. Postbiotics, which are a step beyond probiotics, have emerged as a promising alternative to live microbial cells. While offering stability and safety, postbiotics improve efficacy and avoid the risks associated with live microorganisms. Key metabolite substances such as bacteriocin, peptides, and exopolysaccharides exhibit biological activities, thereby improving food preservation and functional enhancement. This comprehensive review aims to provide know-how for postbiotics' technological, functional, and health-promoting applications across various food systems. Advanced transport mechanisms for delivering postbiotics, such as encapsulation, nanoemulsions, and microfluidic microspheres, have created effective postbiotic delivery systems (PDS). Despite significant progress, mechanistic understanding, production standardization, and regulatory frameworks are still not well understood. Therefore, in-depth research into transport mechanisms and global compliance standards will ensure safe and reproducible applications of postbiotics. Future innovations that integrate agro-industrial by-product bioconversion, advances in omics technologies, and AI-assisted modeling will further support the circular bioeconomy, optimization, and functional prediction from a sustainability perspective.