The three major components of a sauce are liquid, flavoring or seasoning, and starch or thickening agents.
Theses are all very important facets of high quality sauces.
The product that is being prepared and how it is served will determine the correct starch that should be used. This is why it is very important to have a working understanding of how and why starch works. Amylase is straight in shape and has a stronger gelatinous value than amyl pectin because it has the ability to interweave with other chains to form a mesh or netting that traps any free flowing water. Hot water has this reaction because the energy from the heat causes these molecules to bounce around constantly unlike that of cold water, which just allows the starch to disperse and settle at the bottom. Amyl pectin chains from in the shape of clusters making it harder to interweave.