|MadSci Network: General Biology|
There is no specific name for starch from potatoes, it is just called "potato starch". Most native starches, whether from roots, tubers or cereals contain more amylopectin (the branched chain molecule) than amylose (the generally linear molecule). This affects the physical properties of the starch, things like how well it thickens, whether cooking it with water forms a thick paste or thin gruel. The branched chain starches are used in instant puddings and they remain soft after they are prepared whereas the more linear starches form a solid mass almost like a gel when cooked. Generally tuber and root starch have about 80% amylopectin and 20% amylose, whereas, cereal starches (corn, wheat, rice, etc.) contain about 75% amylopectin and 25% amylose. Potato differ from one variety to another and new varieties and cultivars are expanding the definitions. For example, "waxy-type" cereals and roots contain 100% amylopectin and no amylose. Scientists are continuing to change starch make-up at the molecular level. This is an interesting question and an interesting area of study. Sincerely, Phyllis Stumbo University of Iowa U.S.A.
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