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There
are 2 varieties of this plant. The sweet variety, Manihot esculenta
contains a lower level of cyanic acid and its skin of the root is light
green. The bitter variety, Manihot utilissima, contains more
cyanic acid and its skin of the root is brown. In the root, the skin
contain the most amount of hydrocyanic acid. The
skin should be removed before cooking. The poison is the hydrocyanic
acid produced by hydrolizing the chemical ingredients of linamarin and
lnamarase. Before the root is fully cooked or the cyanic acid has not
been destroy, the toxin may turns into hydrogen cyanide.
The symptoms can be nausea, vomiting, diarrhea, dizziness
and in serious cases the patient can die from respiratory failure.
It can also cause the swelling of the thyroids, damage the optic nerve
and the motor nerve.
The tubers of
Manihot utilissima can not be safely stored
even storing in cool place. Characteristics of damage of the tubers
is the discharge of some dark blue color. It is due to formation of
cyanide that is toxic to humans.
木薯品種有甜木薯(Manihot
esculenta )苦木薯(Manihot utilissima)
兩種，甜木薯種的塊根含較低的氰酸，表皮呈淡青色；苦木薯 的塊根含多量的氰酸，表皮呈褐色，兩者不難區別。塊根又以皮層
含氫氰酸最高，因此，木薯要先剝去外皮，煮熟後才能食用。木薯中毒系由其所含亞麻苦甙
(linamarin) 及亞麻苦苷酶
(linamarase)
水解後析出游離的氫氰酸(hydrocyanic acid）所
致。塊根未煮熟或氰酸(cyanic
acid)未完全分解前就拿來食用，內含的毒素會轉化為氰化氫
(hydrogen cyanide)。
中毒症状：輕者噁心、嘔吐、下痢、昏眩；嚴重者呼吸衰竭而死亡。還可引起甲狀腺腫，並會傷
害視神經和運動神經等。[1]
苦木薯不能安全地存儲，即使在陰涼處存放。塊莖損傷的特點是一些深藍色的排出物。這是
由於氰化物的形成，是對人體有毒。
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