Determination of Rutin in Buckwheat Foods by High Performance Liquid Chromatography

Studies on Buckwheat Rutin Part I

Abstract

A simple method was developed for determining rutin in buckwheat flour by highperformance liquid chromatography (HPLC). Rutin was extracted with hot methanol and separated by HPLC on a column packed with Nucleosil 7C₁₈(NAGEL) by using 2.5% acetic acid, methanol and acetonitrile (35:5:10) as a mobile phase and detector set at 350nm.With this method, amounts of rutin in commercial buckwheat flours and buckwheet foods were determined. There were differences in the amounts of rutin among different species of buckwheat (12-22mg/100g). And remarkable differrences existed in buckwheat flours were determined. There were differences in the amounts of rutin among different species of buckwheat (12-22mg/100g). And remarkable differrences existed in buckwheat flours processed in a gradual milling system (4-33mg/100g). The amount of rutin was low in roasted buckwheat grain (soba-tea) or steamed buckwheat grain (soba-mai), but rutin was rather stable with sterilization by super heated steam or γ-ray irradiation. The amounts of rutin in commercial buckwheat noodles (made from buckwheat and wheat flour-water dough and sold in raw or dried state) were from 1 to 15mg/100g. It was confirmed that rutin in buckwheat noodles decreased as cooking-time increased.