Page 104 - Medicinal Plants_PharmD general

 Amylohemicellulose: calcium, magnesium and iron salt of silicic and
phosphoric ester of polysaccharide. It is insoluble in water and gives
blue colour with iodine.

Formation of starch:

Starch occurs in the form of granules of varying size in almost all
organs of plants. Starch is found most abundantly in roots, rhizomes, fruits
and seeds, where it usually occurs in the form of larger grains than to be
found in the chlorophyll containing tissues of the same plant. The small
grains of starch formed in many leaves and stems by the condensation of
sugars are afterwards hydrolysed into sugars so that they pass in solution
to the storage organs where, under the influence of leucoplasts, large grains
of reserve starch are formed. The simplest method of expressing these
changes is as follows:

Condensation n C6H12O6
glucose
(C6H10O5)n + nH2O

Starch Hydolysis

Properties of Starch:

Starch is white in colour. It is insoluble in ordinary organic solvents,
it is insoluble in cold water but forms a colloidal solution on boiling, and
on cooling, it forms a translucent jelly i.e. gelatinisation.

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