Fenugreek Seeds, Leaves, and Derived Ingredients: Chemistry, Structure-Function Relationships, and Food-System Applications.

Fenugreek (Trigonella foenum-graecum L.) is an edible legume with applications in food, health, and agriculture. This review examines the chemistry, extraction-dependent changes, structure-function relationships, food applications, health relevance, and safety of fenugreek seeds, leaves, sprouts, and derived ingredients. Seeds contain abundant galactomannan and proteins, together with steroidal saponins, trigonelline, 4-hydroxyisoleucine, diosgenin, fixed oils, and aroma-active constituents. Leaves are characterized by phenolic and volatile compounds, vitamins, and minerals, while sprouts contain flavonoids and specialized metabolites. Extraction and processing influence the composition, molecular structure, and functionality. Galactomannan- and protein-rich seed fractions contribute to hydration, thickening, emulsification, and foaming, whereas phytochemical constituents exhibit antioxidant and enzyme-inhibitory activities and are associated with glucose and lipid regulation and modulation of inflammatory responses. Fenugreek is also used as a forage and intercropping crop and is well adapted to arid and semiarid conditions. Future studies should improve chemical standardization, food-matrix validation, sensory acceptability, dose relevance, and product-specific safety.