Glycosidases and glycanases of wheat flour doughs

Abstract

Wheat flour contains hydrolytic enzymes capable of reducing dramatically the viscosity of the aqueous solution obtained by high‐speed centrifugation of dough. Indirect evidence suggests this reduction in viscosity is largely due to the hydrolysis of glycosidic linkages in the non‐starch polysaccharides. Soluble proteins and starch contribute less to the viscosity of this dough liquor than do the flour gums. The glycanases in flour relatively rapidly hydrolyse the galactomannan, guaran and carboxymethylcellulose. Flour also contains a wide range of enzymes capable of hydrolysing nitrophenyl α‐ and β‐glucosides, α‐ and β‐galactosides, α‐ and β‐mannosides, α‐arabinoside, β‐fucoside and β‐xyloside. Both the glycanases and the glycosidases show pH optima within the range 4‐6 which covers the range normally encountered in dough.