Dietary Plant-Derived Phenolic Acids and Phenolamides as Natural Preservatives: Antibacterial, Antioxidant and Food Preservation Applications

Food spoilage from microbial contamination and oxidation drives the search for natural preservatives. Phenolic acids (PAs) and phenolamides are plant-sourced metabolites with broad-spectrum antimicrobial and antioxidant activities. This review comprehensively examines their sources, classification, structure–activity relationships, and multi-target mechanisms. PA antimicrobial action involves membrane disruption, intracellular acidification, and oxygen species generation, while antioxidant effects rely on hydrogen donation and metal chelation. For phenolamides, antimicrobial evidence is largely indirect, based on computational docking and one non-food nucleotide biosynthesis study, and direct validation of these mechanisms in food matrices against common foodborne pathogens is lacking. Delivery strategies (direct incorporation, encapsulation, edible coatings, active packaging) are critically evaluated, with emphasis on PA-grafted chitosan systems. Applications of PAs in fruits, vegetables, meat, aquatic products, and lipid-rich emulsions are summarized. Phenolamide applications are limited by low natural abundance, high purification costs, poor aqueous solubility, and a historical bias toward pharmacology. Safety assessments confirm favorable profiles for many PAs and select phenolamides, though chronic toxicity data for phenolamides remain limited. This review provides a theoretical framework for leveraging PAs and emerging phenolamides as natural preservatives and identifies critical knowledge gaps requiring future investigation.