Abstract
For the quantitative determination of buckwheat flour contained in buckwheat foods, rutin analysis was applied. As to the mixture of buckwheat and wheat flours, it was possible to estimate the concentration of buckwheat flour by rutin analysis. But in the case of buckwheat noodles (made from buckwheat and wheat flour-water dough), the estimation was not necessarily accurate. Because in the processing or preserving of buckwheat noodles, the amount of rutin partially dicreased in course of time. And this phenomenon was estimated to be due to the enzymatic degradation of rutin. The rate of decrase was innuenced by the amount of water added to the buckwheat and wheat flours. The decrease was not observed in buckwheat flour sterilized by super heated steam, but was observed in buckwheat flour sterilized by γ-ray irradiation. The decrease of rutin and the increase of quercetin were confirmed in a HPLC pattern. Rutin degrading activity was high in the embryo and "amakawa" fraction (rich in pericarp of dehulled grain). The enzymatic activity in water extract of buckwheat flour was deactivated by heating to 60°C, for 15 min.
