On food and cooking the science and lore of the kitchen ( PDFDrive ) 874

relatively loose, weak clusters. This
differenceexplainswhylong-grainriceshigh
inamylosehaveafirm,springytexturewhen
served right after cooking and get inedibly
hardwhenrefrigeratedovernight,whileshortgrain rices low in amylose have a softer,
sticky texture and harden much less during
overnight refrigeration. The hardness of all
leftover grains can be largely remedied
simply by reheating and so regelating their
starch.

Starch gelation and retrogradation. Starch
granules are compact, organized masses of
long starch chains (left). When a starchy
cerealiscooked,waterpenetratesthegranule
andseparatesthechainsfromeachother,thus
swelling and softening the granule in the
process called gelation (center). When the


cooked cereal cools down, the starch chains
slowly rebond to each other in tighter, more
organized associations, and the granule
becomes firmer and harder, a process called
retrogradation(right).
Starch Firming Can Be Useful Reheated
grains never get quite as soft as they were
whenfirstcooked.Thisisbecauseduringthe
process of retrogradation, amylose molecules
manage to form some clusters that are even
morehighlyorganizedthantheclustersinthe

original starch granule, crystalline regions
that resist breaking even at boiling
temperatures.Theseregionsactasreinforcing
junctions in the overall network of amylose
and amylopectin molecules, and give the
granulesgreaterstrengthandintegrity.Cooks
take advantage of this strengthening to make
bread puddings and starch noodles; parboiled
(converted) rice and American breakfast
cerealskeeptheirshapebecausemuchoftheir