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< prev - next > Food processing Fruits vegetables and roots KnO 100651_Potato Storage (Printable PDF)
The potato (Solanum tuberosum) is a
starchy tuber of the Solanaceae
family. It is thought to have
originated in the Andes region, where
there are other closely related
cultivated potato species. Potatoes
were introduced outside the Andes
400 years ago, and are now an
integral part of the world's cuisine,
being the fourth-largest food crop
after rice, wheat, and maize.
Following centuries of selective
breeding, there are now over a
thousand different types of potatoes
and nearly 4000 different varieties
(Figure. 1).
Approximately 80 varieties are
commercially available in countries
outside Latin America, and these
are grouped either according to their
colour (e.g. russets, reds, whites,
yellows and purples), or for culinary
and processing purposes, varieties
Figure 1: Potatoes on display at the festival of native
potatoes in Peru. There are 256 varieties of potato that
can survive the harsh conditions of the high Andes.
Practical Action is helping families living at altitudes of
3800ft to maintain this crucial biodiversity by developing
varieties of local potatoes, as well as improve technical
aspects of production. Photo: Soluciones Prácticas.
that are described in terms of their
texture: floury potatoes that are
baked or roasted have more starch
(2022%) compared to waxy boiling potatoes (1618%). There are also differences in the
type of starch present in each type: amylose, a long-chain molecule, diffuses out of the starch
granule when floury types are cooked in water, whereas waxy varieties that contain a higher
amount of highly-branched amylopectin molecules retain their shape when boiled. Different
types of potatoes are described on the European Cultivated Potato Database at
Potatoes contain toxic compounds known as glycoalkaloids; the most common being solanine.
The toxin affects the nervous system, causing headaches, diarrhoea, cramps, weakness and
confusion. Solanine content in potato tubers is increased by exposure to light, physical
damage, and age, and the highest concentrations occur just underneath the skin. However,
exposure to light also causes greening due to chlorophyll production, which gives a visual
warning that these areas of the tuber may have become more toxic.
Storage facilities for potatoes need to be carefully designed to slow the natural process of
decomposition, and it is essential that the storage area is dark and well-ventilated. New
potatoes are sensitive to chilling injury and should be stored at 13 - 15°C with 85-90%
relative humidity for up to a few weeks. For short-term storage of mature potatoes,
temperatures of 7 - 10°C are preferred. If potatoes are stored above approx. 10oC they sprout
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