When starch is added to products as an ingredient, however,it is the functional properties of the starch that are usually important, not the calories. Starch is the main thickener in gravies, sauces, and puddings. It absorbs water, and becomes a gel when cooked. As the starch swells up with water, the amylose leaches out, and the amylopectin forms the gel. Some starches have higher amyl content, and make better gels than those containing lots of amylose. As a thickener(as opposed to a gel), it is the amylose that has the main function. The long water-soluble chains increase the viscosity, and that viscosity doesn't change much with temperature.