In general, the components of a sauce that create its consistency have little or no flavor of their own. They therefore only dilute whatever flavors the sauce has. Thickening agents also actively reduce the effectiveness of the flavor molecules in the sauce. They bind some of those molecules so that our palate never senses them, and they slow their movement from the sauce into our taste buds or nasal passages. Because aroma molecules tend to be more fat soluble than water soluble, fat in a sauce hangs onto aroma molecules and decreases aromatic intensity. Amylose starch molecules trap aroma molecules (the aroma molecules in turn make the starch molecules more likely to bond to each other into light-scattering, milky aggregates). And wheat flour binds more sodium than pure starches, so flour-thickened preparations require more added salt than starch-thickened sauces.