This statement is not accurate. The process of breaking down disaccharides into monosaccharides, known as hydrolysis, typically involves the addition of a water molecule. However, the number of water molecules added can vary depending on the specific disaccharide being broken down.

For example, when the disaccharide sucrose is broken down into its component monosaccharides, glucose and fructose, one water molecule is added during the process. However, when the disaccharide lactose is broken down into its component monosaccharides, glucose and galactose, two water molecules are added during the process.

Therefore, the statement that only one water molecule is added during the process of disaccharides change back to monosaccharide is not always true. The exact number of water molecules added depends on the specific disaccharide being broken down.