Protein–Anthocyanin Interactions in Food Systems: A Reaction‐Network Perspective on Equilibria, Kinetics, and Degradation Pathways

Anthocyanins are attractive natural colorants, but their application is limited by poor stability resulting from the interplay between reversible transformations and irreversible degradation processes. In aqueous systems, color expression and persistence depend on the distribution and reactivity of multiple interconverting species that respond sensitively to their chemical environment. Among the strategies explored to improve anthocyanin stability, interactions with proteins have emerged as a promising yet mechanistically underexplored approach. Most studies describe these systems mainly in terms of binding affinity, offering limited insight into their chemical consequences.This review re‐examines protein–anthocyanin interactions through a reaction‐network perspective, where proteins act as modifiers of anthocyanin speciation and transformation pathways. Distinct interaction regimes are observed across protein classes. Serum albumins function as site‐specific modulators that stabilize quinoidal species and shift proton‐transfer equilibria, directly influencing color expression. In contrast, caseins and plant proteins behave primarily as heterogeneous multivalent systems, where reduced hydration, molecular confinement, and, in some cases, covalent coupling suppress degradation without strong species selectivity.By relating interaction mechanisms to their effects on anthocyanin reactivity and stability, this review provides a framework connecting molecular interactions with system‐level behavior, supporting the rational design of more stable and tunable anthocyanin‐based color systems for complex food matrices.