On food and cooking the science and lore of the kitchen ( PDFDrive ) 873

granulesarealmostpureamylopectin.
TheProportionsofProteinsinSeeds

Cooking Separates Starch Molecules and
Softens Granules When a seed is cooked in
water, the starch granules absorb water
molecules, and swell and soften as the water
molecules intrude and separate the starch
molecules from each other. This granule
softening, orgelation, takes place in a
temperature range that depends on the seed
and starch, but is in the region of 140–
160ºF/60–70ºC. (The conversion of solid
starchintoastarch-watergelisoftenreferred
toas“gelatinization,”butthisisunnecessarily
confusing; starch has nothing to do with


gelatin.) The tightly ordered clusters of
amylose
molecules
require
higher
temperatures, more water, and more cooking
time to be pulled and kept apart than do the
looser clusters of amylopectin molecules.
Thisiswhylong-grainChinesericesaremade
with more water than short-grain Japanese
rices.
Cooling Reorganizes Starch Molecules and
FirmsGranulesOncethecookingisfinished

and the seeds cool down below the gelation
temperature,thestarchmoleculesbegintoreform some clusters with pockets of water in
between,andthesoft,gelatedstarchgranules
begintofirmupagain.Thisprocessiscalled
retrogradation. The simpler amylose
molecules start bonding to each other again
almost immediately, and finish within a few
hours at room or refrigerator temperatures.
Sprawling,bushyamylopectinmoleculestake
a day or more to reassociate, and form