On food and cooking the science and lore of the kitchen ( PDFDrive ) 1512

Polysaccharides, which include starch and
cellulose, are sugarpolymers, or molecules
composedofnumerousindividualsugarunits,
asmanyasseveralthousand.Usuallyonlyone
or a very few kinds of sugars are found in a
given polysaccharide. Polysaccharides are
classified according to the overall
characteristics of the large molecules: a
general size range, an average composition,
and a common set of properties. Like the
sugars of which they’re composed,
polysaccharides contain many exposed
oxygenandhydrogenatoms,sotheycanform
hydrogen bonds and absorb water. However,
they may or may not dissolve in water,
depending on the attractive forces among the
polymersthemselves.
Starch By far the most important
polysaccharide for the cook isstarch, the
compact, unreactive polymer in which plants


storetheirsupplyofsugar.Starchissimplya
chainofglucosesugars.Plantsproducestarch
in two different configurations: a completely
linear chain calledamylose, and a highly
branched form calledamylopectin, each of
whichmaycontainthousandsofglucoseunits.
Starch molecules are deposited together in a
series of concentric layers to form solid
microscopic granules. When starchy plant

tissueiscookedinwater,thegranulesabsorb
water, swell, and release starch molecules;
when cooled again, the starch molecules
rebondtoeachotherandcanformamoistbut
solidgel.Variousaspectsofstarch—theway
it determines the texture of cooked rice, its
formationintopurestarchnoodles,itsrolein
breads, pastries, and sauces — are described
indetailinchapters9–11.
GlycogenGlycogen,or“animalstarch,”is
ananimalcarbohydratesimilarto
amylopectin,thoughmorehighlybranched.
It’safairlyminorcomponentofanimaltissue