Soluble ascorbic acid is largely confined to the watery parts of fruits and vegetables and represents one of the least chemically stable molecules in the vitamin family. This weak acid is easily destroyed by mild alkali solutions such as baking soda. Once ingested, vitamin C is readily absorbed by the intestines and continues its journey through the watery components of tissues that make up the human body, helping to build collagen protein while doubling as an antioxidant along the way.