Natural Antioxidants in the Stabilisation of Foods: A Critical Narrative Review of Mechanism, Matrix Dependence and Shelf-Life Outcomes

Abstract

Oxidative deterioration remains one of the principal determinants of the sensory, nutritional and economic life of lipid-containing foods, and the substitution of synthetic phenolic additives with plant-, marine- and by-product-derived antioxidants has become a dominant strategy in preservation research. This critical narrative review examines whether the accumulated evidence supports the frequently repeated claim that natural antioxidants deliver dependable improvements in food stability and shelf life. Literature was identified through structured searching of open scholarly databases and citation indexes, supplemented by backward and forward citation tracking and by consultation of regulatory scientific opinions. Appraisal concentrated on mechanistic coherence, matrix realism, adequacy of oxidation markers and the correspondence between reported chemical outcomes and consumer-relevant endpoints. The synthesis is organised around five arguments. Antioxidant capacity measured in homogeneous solution is a weak and sometimes misleading predictor of stabilising performance in structured foods, because efficacy is governed by partitioning, interfacial concentration, transition-metal management and reaction with matrix constituents rather than by intrinsic radical-scavenging reactivity. The evidence base is strongest for muscle foods and bulk oils and appreciably weaker for dried, low-moisture and plant-based matrices. Encapsulation and active packaging alter the location and release kinetics of antioxidants and can convert an ineffective additive into an effective one, yet the supporting studies are dominated by short storage trials with limited replication and inconsistent reporting. Combinations of natural antioxidants behave cooperatively or antagonistically according to redox potential, chelating capacity and matrix composition, and the mechanistic basis of reported synergy is seldom established. Sensory, regulatory and supply-chain constraints, rather than chemical performance alone, frequently determine industrial adoption. Confidence is high that suitably formulated natural antioxidants retard lipid and protein oxidation in specific matrices, moderate that this retardation translates into commercially meaningful shelf-life extension, and low that current screening practice identifies the compounds most likely to succeed. Priorities include matrix-matched efficacy testing, standardised reporting of oxidation endpoints and independent replication under commercially realistic storage conditions.