This invention the low-class distilled spirits residue easily the straw raincoat concentrated extract or the said low-class distilled spirits residue easily offers the straw raincoat filtrate or the gurukoshidaze inhibiter which includes the concentrated extract of supernatant. The gurukoshidaze inhibiter of this invention can also make the blood glucose depressant independence or combining with the fiber characteristic substance.本発明は、焼酎残渣もろみの濃縮エキスまたは該焼酎残渣もろみの濾液もしくは上清の濃縮エキスを含むα-グルコシダーゼ阻害剤を提供する。本発明のα-グルコシダーゼ阻害剤は、単独または繊維性物質と組み合わせて血糖降下剤とすることもできる。
