the answer is no. If blanched, it will destroy the mucosa on the surface of yam, cause damage to globulin and loss of nutrients. The correct way is: before cooking, soak it in water to prevent the yam from turning black. When cooking, cook as soon as possible to prevent oxidation and nutrient loss. Yam is rich in crude protein, crude fiber, a variety of trace elements and amino acids. It is a dual-purpose plant for medicine and food. It also contains protein, fat, vitamins and minerals, especially iron and calcium. It is recognized as a "scavenger" and is known as "the meat in the vegetarian diet".