From the color point of view, high-quality tofu is even milky white or light yellow, slightly shiny, and a large part of light yellow comes from carotene, which can maintain the health of eyes and skin, improve night blindness and rough skin, and help the body avoid free radicals. Riboflavin in tofu is also yellowish, which can maintain the health of skin, mouth and eyes. In addition, light yellow tofu also implies that there are many flavonoids, which play an important role in improving blood circulation, lowering cholesterol and improving human immunity. Inferior tofu is dark gray, dark yellow or reddish brown, and white tofu may be added with whitening agent.

Light yellow tofu is pure natural, with few additives and many nutritional functions. Whitening agent or sodium bicarbonate may be added to the white tofu. Commonly used in industrial bleaching agents, reducing agents, etc. Hanging white block, also known as carved white block and carved white powder, is soluble in water and is a strong carcinogen, which is extremely harmful to human lung, liver and kidney.