Starch stiffened Elizabethan ruffs long before it thickened modern gravy
The word starch comes from a Germanic root meaning strong or stiff, and German Stärke still means both strength and starch. For centuries its big uses were stiffening linen and sizing yarn; laundry starch made the huge ruffed collars of the sixteenth century possible. People were grinding starchy plants on stone as far back as 100,000 years ago.
Archaeologists have found sorghum starch grains on grinding stones in caves at Ngalue, Mozambique, up to 100,000 years old, and flour from cattail roots on European stones about 30,000 years old. Ancient Egyptians may have glued papyrus with wheat starch paste. Pliny the Elder described how to extract it around 77 to 79 CE, and Romans put it in face creams, hair powder and sauces. Chinese papermakers coated sheets with rice starch from 700 CE, and paper sized with wheat starch followed in the Arab world by the mid-eighth century. Papermaking remains its main non-food use.
Plants make it to save sugar for later. Photosynthesis produces glucose, but dissolved glucose is bulky and draws in water, whereas starch is insoluble and can be packed tightly into granules. Leaves build a temporary supply by day and burn it overnight when there is no sunlight; seeds, tubers and tree twigs store it for the next growing season. Granule size is almost a fingerprint: rice grains measure about 2 micrometres, potato up to 100, and wheat oddly comes in two distinct sizes.
Chemically, starch is glucose linked into chains. Amylose forms long, spiralling strands, while amylopectin branches repeatedly; most starches are about a quarter amylose and three quarters amylopectin. Animals store energy in glycogen, an even more branched relative. The Greek name amylon, meaning not milled, survives in words like amylose. Waxy maize and glutinous rice contain almost pure amylopectin, making smoother, more stable pastes, while high-amylose maize is grown for resistant starch that the gut struggles to digest.
Industry processes tens of millions of tonnes a year, 73 million by 2011. Enzymes chop it into dextrins and then into sugars for syrups; in 2017 the United States turned about 8.2 million tons into high-fructose syrup, and fermenting starch sugars gives beer, whisky and biofuel. Dry heat also breaks starch into brownish dextrins, part of why toast turns golden.
Source: Starch
