Starch Firming Can Be Useful

Reheated grains never get quite as soft as they were when first cooked. This is because during the process of retrogradation, amylose molecules manage to form some clusters that are even more highly organized than the clusters in the original starch granule, crystalline regions that resist breaking even at boiling temperatures. These regions act as reinforcing junctions in the overall network of amylose and amylopectin molecules, and give the granules greater strength and integrity. Cooks take advantage of this strengthening to make bread puddings and starch noodles; parboiled (converted) rice and American breakfast cereals keep their shape because much of their starch has been allowed to retrograde during manufacturing. And it turns out that retrograded starch is good for our bodies! It resists our digestive enzymes and therefore slows the rise in blood sugar following a meal, and feeds desirable bacteria in the large intestine.