lactose vs maltose

lactose

noun
  • The disaccharide sugar of milk and dairy products, C₁₂H₂₂O₁₁, a product of glucose and galactose used as a food and in medicinal compounds. 

maltose

noun
  • A disaccharide, C₁₂H₂₂O₁₁ formed from the digestion of starch by amylase; is converted to glucose by maltase; it is an isomer of trehalose 

How often have the words lactose and maltose occurred in a corpus of books? (source: Google Ngram Viewer )