Grievance casebook Steamed sweet potato green change

When steamed sweet potatoes were kept in the refrigerator overnight, the inside and center of the sweet potato skin turned green.

When other steamed sweet potatoes and cotton containing ammonia without any green change were placed in a sealed container and left unchecked, a similar green change was seen. In addition, the higher the ammonia concentration, the darker the green changes.

Green variation is due to a green substance formed by the reaction of chlorogenic acid, a trace component in sweet potatoes, and ammonia. The effect on the human body is unknown.

Sweet potatoes turn green due to a small amount of ammonia gas made by rot bacteria in the refrigerator, so cleaning and sterilization in the refrigerator can be carried out to prevent green change by keeping the inside of the refrigerator clean.

Food complaint handling casebook Edited by the National Food Sanitation Monitoring Council

Published on March 8, 2007