Is popcorn a pure substance or a mixture of different substances?

Popcorn that is popped from one kind of corn that has nothing added to it would be a pure substance if you consider popcorn to be a substance. However, popcorn itself is made up of many different substances. So the answer is either yes or no, depending on what you are talking about.

Popcorn is a foodstuff derived from maize and therefore contains a complex mixture of carbohydrates, proteins and fats. The carbohydrates predominate with starch and cellulose as the major components. The former is digestible and the latter is not contributing to dietary roughage or fibre. The popping is achieved when the residual water in the dried maize kernel turns to steam in the presence of heated oil or microwaves and puffs out the starchy interior.

Popcorn, like most natural products, is a mix of substances. Corn contains sugars (glucose and fructose), starch (a long chain of glucose strung together), cellulose (even more glucoses, undigestible aka fibre), protein (long strings of amino acids) and other trace chemicals.

Pure substances contain only _one_ type of molecule such as sugar (99.9% pure sucrose) or water (H2O). Mixtures contain more than one type of molecule.

Is it a homogeneous mixture or heterogeneous mixture?