此外，一定比例的碳酸氢钠和碳酸氢铵混合作为化学膨松剂有利于产品结构疏松多孔，降低产品硬度。
Besides , a certain proportion of sodium bicarbonate to acid ammonium carbonate is conducive to porosity of product structure and the reduction of product hardness .
化学膨松剂