Effect of Sodium Bicarbonate on Rutin Residual Ratio in Tartary Buckwheat (Fagopyrum tataricum Gaertn.) Dough

Although Manten-Kirari is a new Tartary buckwheat variety with trace rutinosidase activity, the trace levels of rutinosidase gradually hydrolyze rutin in dough. In addition, contamination from normal rutinosidase varieties can sometimes hydrolyze rutin during dough making. To reduce the hydrolysis, we evaluated the effects of sodium bicarbonate (NaHCO3). The following variables were adjusted: water content, blending ratio of Tartary buckwheat flour, and dough storage temperature. The rutin residual ratio increased with decreasing dough storage temperature, water content, and time after addition of water, and with increasing NaHCO3 concentration. Addition of 0.5% NaHCO3 can prevent rutin hydrolysis almost completely in dough made from Manten-Kirari. When the contamination rates from normal rutinosidase varieties was less than 1%, addition of NaHCO3 to dough made from Manten-Kirari under low-temperature storage of dough (5 °C) can retain a rutin residual ratio of more than 80% for a water content of 30% for up to 2 hours after addition of water.