Composition change of buckwheat (Fagopyrum esculentum moench) groats after soaking in cold water

Abstract

The effects of soaking at low temperature on food composition of buckwheat (Fagopyrum esculentum Moench) groats were investigated. From the Edo period this treatment carried out to improve eating qualities of Japanese buckwheat noodle, for example, increase of sweetness, decrease of bitter taste and better feeling on the tongue. Buckwheat seeds were soaked in cold water in 2 weeks and traditionally dried outdoors in winter season at southern Zao area in Yamagata prefecture. Two kinds of buckwheat seeds, before and after soaking in cold water, were prepared to groats. Components were determined using flour of whole groats. After soaking in cold water, almost protein, lipid, carbohydrate, minerals, dietary fiber, and rutin in groats did not elute. However polyphenol was decreased and free amino acids composition was changed. Among of free amino acids, γ-amino-nbutyric acid (GABA) was estimated twice as quantity as before soaking in cold water. These results did not indicate drastically, but showed the possibility of improvements on buckwheat noodle qualities.