From Underutilized Tuber to High-Value Food Resource: Advances in Bioactive Components, Processing Technologies and Sustainable Valorization of Tiger Nut (Cyperus esculentus L.)

Tiger nut (Cyperus esculentus L.) is a perennial herb of the family Cyperaceae whose underground tubers supply oil, starch, protein and dietary fiber, making it an emerging composite tuber resource. Earlier reviews described composition or addressed oil alone; here, structure–function relationships are the analytical core, and this review asks how molecular and structural knowledge of its components can be translated into designed functionality within a value-chain upgrading frame. A systematic search of four databases yielded 100 peer-reviewed studies together with the four standards and regulations that govern the sector, which were assessed on a common evidence scale separating mechanistic findings from correlative ones. Multi-omics has identified the genes and networks underlying tuber enlargement and the high-oil, high-oleic-acid phenotype. Tuber lipids, polyphenols, peptides, polysaccharides and dietary fiber display antioxidant, gut microbiota-modulating, metabolic and immunomodulatory activities; however, human clinical evidence remains scarce. Green extraction, physical-field and enzymatic treatments can direct the structural control and functional enhancement of oil, protein and starch, supporting plant-based beverages, bakery products, fat replacers and Pickering delivery systems, while cascading biorefinery converts processing residues. Transfer from laboratory prototype to industrial product is blocked by unresolved structure–activity relationships, weak evidence grading, imprecise processing and absent standardization; research and industrialization priorities are proposed.