Why do food scientists modify starches?

Starches are used to thicken food products by absorbing liquid. However, when a food is heated or frozen, the liquid comes out of the starch (this is called syneresis).

To prevent this, food scientists modify the starches so that they can hold water better. The two ways that starches are modified are by cross-linking and derivatization. These methods help hold starch molecules together or they create pockets in the starch where liquid is trapped.