Influence of processing on flavonoid retention, transformation, and bioavailability in Tartary buckwheat (Fagopyrum tataricum): a review

Buckwheat is a traditional food and medicinal crop valued for its nutritional composition and high levels of bioactive compounds. Among buckwheat species, Tartary buckwheat is particularly rich in flavonoids, especially rutin and quercetin, which are associated with antioxidant, hypoglycemic, lipid-lowering, antihypertensive, and anti-inflammatory effects. However, the concentration and stability of these compounds are strongly influenced by processing. This review summarizes how non-thermal processes (milling, soaking, germination, and fermentation) and thermal treatments (boiling, steaming, roasting, and extrusion) affect the distribution, transformation, and retention of flavonoids in Tartary buckwheat. The evidence shows that optimized processing can enhance flavonoid bioavailability, reduce antinutritional factors, and improve product quality, enabling the development of functional Tartary buckwheat foods with improved nutritional and health-promoting value. The review concludes that standardised processing conditions and better understanding of flavonoid transformations are essential to maximize health benefits and support industrial application of Tartary buckwheat products.