Tetrahydropyridines

Tetrahydropyridines (THPs) are a class of keto-cyclic imines found in lambic that are responsible for odors described as "mousey" or "cat pee" in low concentrations and tortilla chips or Cheerios in higher concentrations. Formed by the Maillard reaction, THPs are primary odor components in many familiar baked foods, such as breads, tortillas, and crackers.

Chemical and physical properties

There are three primary forms of THP found in lambic. In increasing odor thresholds, they are: ATHP, ETHP, and APY, each of which may themselves be composed of several closely-related compounds.

ATHP

ETHP

APY