- common name
applied to a perennial, trailing herb of the bindweed family. The plant,
which is native to tropical America, is cultivated on sandy or loamy
soils throughout many warm regions of the world, and exists as an important
food staple in a number of countries. It is planted primarily for its
thick, edible roots, called sweet potatoes. The name is due to a sugar
content. Two main types are commonly cultivated: a dry, mealy type,
and a soft, light-to-deep-yellow, moist-fleshed type. The species often
called wild sweet-potato vine, manroot, or man-of-the-earth is not edible,
but is cultivated as an ornamental vine.
generally make up between 80 to 90
% of the dry weight of sweet potato roots. The sweet potato yields an
important starch, which is used as a food starch in noodles etc. and
technically for sizing textiles and papers, for the manufacture of adhesives
and in laundries. The process of extracting and refining the starch
is similar to the potato starch process. The pink and yellow varieties
are rich in carotene, the precursor of vitamin A.
Sweet potato starch granules vary from 4 to 40 microns with 19 micron
in average. The small granules affect extraction procedures in
particular the dewatering. The amylose content is 19% - 25%.
The sweet potato belongs
to the family Convolvulaceae. It is classified as Ipomoea batatas. The
species called wild sweet-potato vine, manroot, or man-of-the-earth
is classified as Ipomoea pandurata.
Viscosity profile of 9% sweet potato starch slurry
on Rapid Visco-Analyzer (RVA) model 3D.
China is the world's largest sweet potato producer, accounting for
80-85 percent of global production. The majority of China's sweet potato
is grown in seasonal rotations with other staple crops and is used for
animal feed or to produce noodles and industrial starch.
Sweet potatoes grow year-round in the tropics. Sweet potato has the
shortest growing cycle of the root crops grown in the tropics. The crop
is normally harvested about 4 months after planting and harvesting may
be spread over several months. In a temperate climate harvest must take
place before risk of frost.