What happens to the muscles in the small intestine as the food moves
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The movement pushes food and liquid through your GI tract and mixes the contents within each organ. The muscle behind the food contracts and squeezes the food forward, while the muscle in front of the food relaxes to allow the food to move. The digestive process starts when you put food in your mouth.

The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine, and push the mixture forward for further digestion. The walls of the small intestine absorb water and the digested nutrients into your bloodstream.

Explanation:

not only is it colder, it also becomes darker, less salty, and more dense.