Effect of processing on the flavonoid content in buckwheat (Fagopyrum esculentum Moench) grain

Six flavonoids have been isolated and identified in buckwheat grain. These are rutin, orientin, vitexin, quercetin, isovitexin, and isoorientin. Rutin and isovitexin are the only flavonoid components of buckwheat seeds while hulls contain all six identified compounds. The total flavonoid concentration in the seeds was 18.8 and in the hulls 74 mg/100 g of dry matter. Dehulling the grain by using different temperature regimes resulted in drastic reductions of the total flavonoid concentration in the grain (by 75% of the control) and smaller but significant (15-20%) reduction in the hulls.