Starch
The main complex storage carbohydrate of plants (cereals, tubers, pulses), made of long chains of glucose, and a major energy source in the human diet.
Starch is made of two molecules: amylose (linear chains) and amylopectin (branched chains). It is the form in which plants store energy. During digestion, enzymes (amylases) break it down into glucose.
An original angle (resistant starch through cooling): not all starches are equal. A fascinating and practical fact: cooking then cooling a starchy food turns part of its starch into resistant starch (see the dedicated entry), which escapes digestion and feeds the microbiota.
The mechanism is called retrogradation: as it cools, the amylose chains reassociate into stable structures that resist digestive enzymes. Measured result: white rice cooked then cooled for 24 hours contains up to 258% more resistant starch; boiled then refrigerated potatoes, up to 280% more.
In concrete terms, a cold pasta or potato salad (made the day before) has a much lower glycaemic impact than hot mash. Gently reheating keeps part of the benefit.
This rehabilitates the “unloved” starchy foods: the starchy food itself is not the problem, but its form (hot mash, ultra-digestible = glucose spike) versus its preparation (cooked and cooled = beneficial resistant starch).