Tryptone is an enzymatic digest of casein used as a nitrogen source in culture media. Casein is the main
protein of milk, and a rich source of amino-acid nitrogen. Tryptone is rich in tryptophane, making it valuable
for use in detecting indole production. The absence of detectable levels of carbohydrates in Tryptone makes
it a suitable peptone in differentiating bacteria on the basis of their ability to ferment various carbohydrates.