Even if the raw materials of rice noodles are dry and white, they will brown or change color when exposed to water or high temperature, thus making the color of rice noodles pale yellow. To solve this problem, we usually need: 1, where raw materials exist, they are waterproof and resistant to high temperature; 2, adding whitening agent; Attention should be paid to adding whitening agent: the standard maximum dosage of sulfur is 0.1g/kg;