Protein-Polyphenol Interactions in Specialty Oilseeds: Multiscale Mechanisms, Physicochemical Reshaping, and Advanced Food Applications.

Specialty oilseeds, encompassing herbaceous (sunflower, flaxseed, sesame) and woody (Camellia oleifera, walnut, olive) species, serve as important sustainable sources of plant proteins that are inherently enriched with structurally diverse endogenous polyphenols such as chlorogenic acid, lignans, catechins, and ellagitannins. During processing, these polyphenols drive covalent or non-covalent interactions that profoundly reshape the physicochemical and functional properties of the resulting food systems. While prior reviews have largely remained descriptive or focused on single commodities or model proteins, this work provides the first critical, multiscale synthesis across herbaceous and woody oilseeds. We systematically compare polyphenol diversity, delineate the continuum from reversible non-covalent association (specific residue-level vs. non-specific surface-mediated) to irreversible covalent coupling, and establish a "structure-interaction-function" framework that explicitly defines a condition-dependent "Processing Window". Within this window, moderate interactions enhance interfacial viscoelasticity, oxidative stability, foaming, and emulsification; excessive cross-linking, however, impairs solubility, digestibility, and sensory quality. By integrating experimental spectroscopy (UV-vis, FT-IR, CD, ITC), microscopic imaging, and computational simulations (molecular docking and dynamics), we map residue-level binding modes directly to macroscopic functional outcomes. Furthermore, the review evaluates the engineering potential of these complex systems in frontier applications such as antioxidant emulsions and active packaging. By explicitly identifying evidence boundaries and quantitative knowledge gaps in endogenous matrices, this work provides a comprehensive theoretical framework for the precision design and valorization of specialty oilseed-derived functional ingredients.